Biology Revision

Majeed Thaika Year 10-11   Contents 1 Cells   pg-05 -Animal and plant cells (pg-05) -Specialised cells (pg-06) -diffusion (pg-07) -osmosis (pg-08) 2 Plants . pg-09 -photosynthesis (pg-09) -Factors affecting photosynthesis (pg-10) -Plants and minerals (pg-11) 3 Food Chains and Cycles pg-12 -Food chain (pg-12) -Energy transfer (pg-13) -Pyramids of biomass (pg-15) -efficiency of food production (pg-15) -calculating energy efficiency (pg-16) Shorter food chains (pg-16) carbon cycle (pg-17) 4Enzymes and Digestion   pg-18 -What are enzymes? (Pg-18) -Temperature and enzymes (Pg-18) -Ph and enzymes (Pg-19) -enzymes and respiration (Pg-20) -digestive system (Pg-20) -Enzymes and digestion (Pg-21) -Other substances in digestion (Pg-22) -Enzymes in industry (Pg-23) 5Homeostasis   pg-24 -Removing waste products (Pg-24) -Controlling blood glucose (Pg-25) -Diabetes (Pg-25) -Temperature regulation (Pg-26) – Temperature regulation – Higher (Pg-26) 6Hormones   pg-27 -Hormones a nd glands (pg-28) hormones in the menstrual cycle (pg-29) -Controlling fertility (pg-31) 7The Nervous System   pg-31 -receptors and effectors (pg-31) -Neurones (pg-33) -Reflex action (pg-34) 8Defending against infection   pg-35 -pathogens-bacteria (pg-35) -pathogens-virus (pg-36) -white blood cells (pg-36) -more about white blood cells (pg-37) -vaccination (pg-38) -antibiotics (pg-38) 9Diet and Exercise   pg-40 -nutrients (pg-40) -metabolic rate(pg-41) -the right amount of food (pg-41) -cholesterol(pg-42) -salt (pg-43) 10Adaptation   pg-43 -Adaptation-cold climates (pg-43) -Adaptation-hot climates (pg-44) 11Characteristics and Classification   pg-45 -genetic engineering (pg-45) -selective breeding (pg-45) -changing the characteristics of a species (pg-46) -classification (pg-47) -difficulties with classification (pg-48) 12The Heart   pg-49 -the circulatory system (pg-49) -arteries and veins (pg-50) -the heart (pg-50) -causes of heart disease (pg-51) 13Extra   pg-51 -se x hormones (pg-51) competition (pg-52) -The nitrogen cycle -the water cycle Cells All animals and plants are made of cells. Animal cells and plant cells have features in common, such as a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Plant cells also have a cell wall, and often have chloroplasts and a permanent vacuole. Note that cells may be specialized to carry out a particular function. Dissolved substances pass into and out of cells by diffusion. Water passes into and out of cells by osmosis. Animal and plant cells Function of cells which animal and plant cells have in common:- Part| Function| ucleus| contains genetic material, which controls the activities of the cell| cytoplasm| most chemical processes take place here, controlled by enzymes| cell membrane| controls the movement of substances into and out of the cell| mitochondria| most energy is released by respiration here| ribosomes| protein synthesis happens here| Extra parts of plant cells:- Part| Function | cell wall| strengthens the cell| chloroplasts| contain chlorophyll, which absorbs light energy for photosynthesis| permanent vacuole| filled with cell sap to help keep the cell  turgid|Diagram: Generalized animal and plant cell Specialised cells Cells may be specialized for a particular function. Their structure will allow them to carry this function out. Here are some examples: Examples of the functions of cells:- Cell| Function| Adaption| Leaf cell| Absorbs light energy for photosynthesis| Packed with chloroplasts. Regular shaped, closely packed cells form a continuous layer for efficient absorption of sunlight. | Root hair cell| Absorbs water and mineral ions from the soil| Long ‘finger-like' process with very thin wall, which gives a large surface area. |Sperm cell| Fertilizes an egg cell – female gamete| The head contains genetic information and an enzyme to help penetrate the egg cell membrane. The middle section is packed with mitochondria for energy. The tai l moves the sperm to the egg. | Red blood cells| Contain haemoglobin to carry oxygen to the cells. | Thin outer membrane to let oxygen diffuse through easily. Shape increases the surface area to allow more oxygen to be absorbed efficiently. No nucleus, so the whole cell is full of haemoglobin. | Diffusion Dissolved substances have to pass through the cell membrane to get into or out of a cell.Diffusion is one of the processes that allow this to happen. Diffusion  occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when the particles are free to move. This is true in gases and for particles dissolved in solutions. Particles diffuse down a concentration gradient, from an area of high concentration to an area of low concentration. This is how the smell of cooking travels around the house from the kitchen, for example. Examples of diffusion Location| Particles move| From| To|Gut| digested food products| gut cavity| blood in capillary of villus| Lungs| oxygen| alveolar air space| blood circulating around the lungs| Two examples of diffusion down concentration gradients:- Remember, particles continue to move from a high to a low concentration while there is a  concentration gradient. In the lungs, the blood will continue to take in oxygen from the alveolar air spaces provided the concent-ration of oxygen there is greater than in the blood. Oxygen diffuses across the alveolar walls into the blood, and the circulation takes the oxygen-rich blood away. OsmosisWater can move across cell membranes because of osmosis. For osmosis to happen you need: * two solutions with different concentrations * a partially permeable membrane to separate them Partially permeable membranes let some substances pass through them, but not others. The animation shows an example of osmosis. Osmosis is the movement of water from a less concentrated solution to a more concentrated soluti on through a partially perm-eable membrane. The picture above shows how osmosis works. Eventually the level on the more concentrated side of the membrane rises, while the one on the less concentrated side falls.When the concentration is the same on both sides of the membrane, the movement of water molecules will be the same in both directions. At this point, the net exchange of water is zero and there is no further change in the liquid levels. Osmosis is important to plants. They gain water by osmosis through their roots. Water moves into plant cells by osmosis, making them  turgid  or stiff so they that able to hold the plant upright. Plants Green plants absorb light energy using chlorophyll in their leaves. They use it to react carbon dioxide with water to make a sugar called glucose.The glucose is used in respiration, or converted into starch and stored. Oxygen is produced as a by-product. This process is called photosynthesis. Temperature, carbon dioxide concentration and li ght intensity are factors that can limit the rate of photosynthesis. Plants also need mineral ions, including nitrate and magnesium, for healthy growth. They suffer from poor growth in conditions where mineral ions are deficient. Photosynthesis Photosynthesis  is the chemical change which happens in the leaves of green plants. It is the first step towards making food – not just for plants but ultimately every animal on the planet.During this reaction,  carbon dioxide  and water are converted into glucose and oxygen. The reaction requires  light energy, which is absorbed by a green substance called chlorophyll. Cross-section through a leaf cell Photosynthesis takes place in leaf cells. These contain chloroplasts, which are tiny objects containing chlorophyll. The equation for photosynthesis is:- Plants absorb water through their roots, and carbon dioxide through their leaves. Some glucose is used for respiration, while some is converted into insoluble starch  for sto rage. The stored starch can later be turned back into glucose and used in respiration.Oxygen is released as a by-product of photosynthesis. Factors limiting photosynthesis Three factors can limit the speed of photosynthesis – light intensity, carbon dioxide concentration and temperature. Light intensity -Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. -Increasing the light intensity will boost the speed of photosynthesis. Carbon dioxide concentration Sometimes photosynthesis is limited by the concentration of carbon dioxide in the air. Even if there is plenty of light, a plant cannot photosynthesise if there is insuff-icient carbon dioxide.Temperature -If it gets too cold, the rate of photosynthesis will decrease. Plants cannot photosynthesise if it gets too hot. -If you plot the rate of photosynthesis against the levels of these three limiting factors, you get graphs like the ones above. -In practice, an y one of these factors could limit the rate of photosynthesis. Maximizing growth Farmers can use their knowledge of these limiting factors to increase crop growth in greenhouses. They may use artificial light so that photosynthesis can continue beyond daylight hours, or in a higher-than-normal light intensity.The use of paraffin lamps inside a greenhouse increases the rate of photosynthesis because the burning paraffin produces carbon dioxide and heat too. Plants and minerals Plants need to take in a number of elements to stay alive. The most important are: * carbon * hydrogen * oxygen Plants get hydrogen and oxygen from water in the soil, and carbon and oxygen from carbon dioxide and oxygen in the atmosphere. Water and carbon dioxide are used to synthesise food during photosynthesis. Oxygen is used to release energy from food during respiration. In addition to these three elements, plants need a number of minerals for healthy growth.These are absorbed through the roots as mineral i ons dissolved in the soil water. Two important mineral ions needed by plants are: * Nitrate  Ã¢â‚¬â€œ for making amino acids, which are needed to make proteins * Magnesium  Ã¢â‚¬â€œ for making chlorophyll If a plant does not get enough minerals, its growth will be poor. It will suffer from deficiency symptoms: * deficient in nitrate – it will suffer from stunted growth * deficient in magnesium – it's leaves will turn yellow The tomato plant on the left is healthy; the one on the right is growing in conditions where mineral ions are deficient Food Chains and CyclesFood chains show the feeding relationships between living things. Pyramids of biomass reveal the mass of living material at each stage in a chain. The amount of material and energy decreases from one stage to the next. Food production is more efficient if the food chain is short, or if energy losses from animals are reduced. The carbon cycle shows how carbon moves from the atmosphere, through various anima ls and plants, then back to the atmosphere again. Food chains A  food chain  shows what eats what in a particular habitat. For example, grass seed is eaten by a vole, which is eaten by a barn owl.The arrows between each item in the chain always point in the direction of energy flow – in other words, from the food to the feeder. The Sun is the ultimate source of energy for most communities of living things. Green plants absorb some of the Sun’s light energy to make their own food by photosynthesis. The other organisms in a food chain are consumers, because they all get their energy and biomass by consuming – eating – other organisms. It helps if you can recall the meaning of some common words used with food chains. Common words used with food chains and their meaning Word| Meaning|Producers| Green plants – they make food by photosynthesis. | Primary consumers| Usually eat plant material – they are herbivores. For example rabbits, caterpil lars, cows and sheep. | Secondary consumers| Usually eat animal material – they are carnivores. For example cats, dogs and lions. | Predators| Kill for food. They are either secondary or tertiary consumers| Prey| The animals that predators feed on. | Scavengers| Feed on dead animals. For example, crows, vultures and hyenas are scavengers. | Decomposers| Feed on dead and decaying organisms, and on the undigested parts of plant and animal matter in faeces. Energy transfer Energy is transferred along food chains from one stage to the next. But not all of the energy available to organisms at one stage can be absorbed by organisms at the next one. The amount of available energy decreases from one stage to the next. Some of the available energy goes into growth and the production of offspring. This energy becomes available to the next stage, but most of the available energy is used up in other ways: * energy released by respiration is used for movement and other life processes, and is eventually lost as heat to the surroundings energy is lost in waste materials, such as faeces All of the energy used in these ways returns to the environment, and is not available to the next stage. The animation shows how the level of available energy goes down as it is transferred through a temperate forest food chain. Most food chains are pretty short. There are rarely more than four stages, because a lot of energy is lost at each stage. Pyramids of biomass Biomass  means the mass of living material at a stage in a food chain. The biomass goes down as you go from one stage to the next, just like the amount of energy.A  pyramid of biomass  is a chart, drawn to scale, showing the biomass at each stage in a food chain. The bars become narrower as you reach the top. This pyramid of biomass is for the food chain: Oak tree > caterpillar > blue tit > sparrowhawk Note that you do not need to draw the organisms. But you must draw your pyramid of biomass to scale. Each bar should be labelled with the name of the organism. Efficiency of food production The efficiency of food production can be improved by reducing the amount of energy lost to the surroundings. This can be done by: * preventing animals moving around too much keeping their surroundings warm Mammals and birds maintain a constant body temperature using energy released by respiration. As a result, their energy losses are high. Keeping pigs and chickens in warm sheds with little space to move around allows more efficient food production. But this raises moral concerns about the lives of such animals. In reality, a balance must be reached between the needs of farmers and consumers and the welfare of the animals. Calculating energy efficiency This bullock has eaten 100 kJ of stored energy in the form of grass, and excreted 63 kJ in the form of faeces, urine and gas.The energy stored in its body tissues is 4 kJ. So how much has been used up in respiration? The energy released by respiration = 100 â₠¬â€œ 63 – 4 = 33 kJ Only 4 kJ of the original energy available to the bullock is available to the next stage, which might be humans. The efficiency of this energy transfer is: Efficiency = 4/100 x 100 = 4% Shorter food chains Food production is more efficient if the food chain is short, because a higher percentage of energy is available to us. The carbon cycle All cells – whether animal, plant or bacteria – contain  carbon, because they all contain proteins, fats and carbohydrates.Plant cell walls, for example, are made of cellulose – a carbohydrate. Carbon is passed from the atmosphere, as carbon dioxide, to living things, passed from one organism to the next in complex molecules, and returned to the atmosphere as carbon dioxide again. This is known as the carbon cycle. Removing carbon dioxide from the atmosphere Green plants remove carbon dioxide from the atmosphere by  photosynthesis. The carbon becomes part of complex molecules such as proteins, f ats and carbohydrates in the plants. Returning carbon dioxide to the atmosphere Organisms return carbon dioxide to the atmosphere by  respiration.It is not just animals that respire. Plants and microorganisms do, too. Passing carbon from one organism to the next When an animal eats a plant, carbon from the plant becomes part of the fats and proteins in the animal. Microorganisms and some animals feed on waste material from animals, and the remains of dead animals and plants. The carbon then becomes part of these microorganisms and detritus feeders. Materials from living things decay because they are digested by microorganisms. This process happens faster in warm, moist conditions with plenty of oxygen. Decay can be very slow in cold, dry conditions, and when here is a shortage of oxygen. Enzymes and digestion Enzymes are biological catalysts. There are optimum temperatures and  pH values at which their activity is greatest. Enzymes are also proteins, and usually denatured above about 45? C. Enzymes are important in respiration. Aerobic respiration releases energy from glucose. What are enzymes? Enzymes are biological catalysts – catalysts are substances that increase the rate of chemical reactions without being used up. Enzymes are also  proteins  that are folded into complex shapes that allow smaller molecules to fit into them.The place where these  substrate  molecules fit is called the  active site. The pictures show how this works. In this example, two small molecules join together to make a larger one. If the shape of the enzyme changes, it’s active site may no longer work. We say the enzyme has been  denatured. They can be denatured by high temperatures or extremes of  pH. Note that it is wrong to say the enzyme has been killed. Although enzymes are made by living things, they are proteins, and not alive. Temperature and enzymes As the temperature increases, so does the rate of reaction. But very high temperatures denature enzymes.The graph shows the typical change in an enzyme's activity with increasing temperature. The enzyme activity gradually increases with temperature until around 37? C, or body temperature. Then, as the temperature continues to rise, the rate of reaction falls rapidly, as heat energy denatures the enzyme. Temper-ature and enzyme activity PH and enzymes Changes in pH alter an enzyme’s shape. Different enzymes work best at different pH values. The optimum pH for an enzyme depends on where it normally works. For example, intestinal enzymes have an optimum pH of about 7. 5. Enzymes in the stomach have an optimum pH of about 2. H and enzyme activity Enzymes and respiration Enzymes in cells catalyse photosynthesis, protein synthesis – joining amino acids together, and aerobic respiration. Aerobic respiration Respiration is not the same thing as breathing. That is more properly called ventilation. Instead, respiration is a chemical process in which energy is released fro m food substances, such as glucose – a sugar. Aerobic  respiration needs oxygen to work. Most of the chemical reactions involved in the process happen in tiny objects inside the cell cytoplasm, called mitochondria. This is the equation for aerobic respiration:Glucose + oxygen >  carbon dioxide + water (+ energy) The energy released by respiration is used to make large molecules from smaller ones. In plants, for example, sugars, nitrates and other nutrients are converted into amino acids. Amino acids can then join together to make proteins. The energy is also used: * to allow muscles to contract in animals * to maintain a constant body temperature in birds and mammals Enzymes are important in digestion. Digestion is the breakdown of carbohydrates, proteins and fats into small soluble substances that can be absorbed into the blood.Lipases and proteases are used in biological detergents, and enzymes are used in the manufacture of food and drink. The digestive system Digestio n is the breakdown of large molecules into smaller, soluble molecules that can be absorbed into the body. Digestion happens inside the gut, and relies on enzymes. This diagram will show you of the main parts of the gut: Enzymes and digestion The enzymes involved in respiration, photosynthesis and protein synthesis work inside cells. Other enzymes are produced by specialised cells and released from them; the digestive enzymes are like this. They pass out into he gut, where they catalyse the breakdown of food molecules. Different enzymes Different enzymes catalyse different digestion reactions. Enzymes and their reactions catalysed enzyme| reaction catalysed| amylase| starch > sugars| protease| proteins > amino acids| lipase| lipids   >   fatty acids + glycerol| Amylase is an example of a carbohydrase. Lipids are fats and oils. Different parts of the gut Different parts of the gut produce different enzymes. Where enzymes are produced enzyme| where produced| amylase| salivary gland s, pancreas, small intestine| protease| stomach, pancreas, small intestine| ipase| pancreas, small intestine| Summary Overall, this means that: * Amylase catalyses the breakdown of starch into sugars in the mouth and small intestine. * Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine. * Lipases catalyse the breakdown of fats and oils into fatty acids and glycerol in the small intestine. Other substances in digestion You should recall that different enzymes work best at different pH values. The digestive enzymes are a good example of this. Enzymes in the stomach The stomach produces  hydrochloric acid.This helps to begin digestion, and it kills many harmful microorganisms that might have been swallowed along with the food. The enzymes in the stomach work best in  acidic  conditions – in other words, at a low pH. Enzymes in the small intestine After the stomach, food travels to the small intestine. The enzymes in the small i ntestine work best in  alka-line  conditions, but the food is acidic after being in the stomach. A substance called  bile  neutralises the acid to provide the alkaline conditions needed in the small intestine. Bile and enzyme production in the liver and pancreas Enzymes in industry Enzyme namesThe names of the different types of enzymes usually end in the letters  -ASE. Three of the most common enzymes with their chemical actions are: * lipase  Ã¢â‚¬â€œ breaks down fats * protease  Ã¢â‚¬â€œ breaks down proteins * carbohydrase  Ã¢â‚¬â€œ breaks down carbohydrates Enzyme uses Enzymes allow certain industrial processes to be carried out at normal temperatures and pressures, thereby reducing the amount of energy and expensive equipment needed. Enzymes are also used in the home, for example, in ‘biological' detergents. The table shows some common enzyme uses you should be familiar with. Uses of enzymes Enzyme| Use| rotease| used to pre-digest proteins during the manu facture of baby foods| lipase| used – together with protease – in biological detergents to break down – digest – the substances in stains into smaller, water soluble substances| carbohydrase| used to convert starch syrup, which is relatively cheap, into sugar syrup, which is more valuable – for example, as an ingredient in sports drinks| isomerase| used to convert glucose syrup into fructose syrup – fructose is sweeter than glucose, so it can be used in smaller amounts in slimming foods| Homeostasis The conditions inside the body must be controlled within narrow limits.This is called homeostasis. These conditions include water content, ion content, body temperature and blood glucose concentration. The thermoregulatory centre is the part of the brain that monitors and controls body temperature. The pancreas meanwhile monitors and controls blood glucose concentration. It produces a hormone called insulin that reduces blood glucose levels. Diab etes is a disease which can be caused by insufficient insulin. Removing waste products Waste products must be removed from the body. If they are not, they will increase in concentration and may interfere with chemical reactions or damage cells.Waste products that must be removed include carbon dioxide and urea. Waste product| Why is it produced? | How is it removed? | carbon dioxide| it is a product of aerobic respiration| through the lungs when we breathe out| urea| it is produced in the liver when excess amino acids are broken down| the kidneys remove it from the blood and make urine, which is stored in the bladder temporarily| Production and removal of waste products Water enters the body through food and drink. It is also a product of aerobic respiration in cells. If the amount of water in the body is wrong, cells can be damaged because too much water enters or leaves them.The pictures show how the amount of water lost as urine is controlled: Controlling blood glucose The pancre as and insulin The  pancreas  monitors and controls the concentration of  glucose  in the blood. It produces a hormone called  insulin. Insulin causes glucose to move from the blood into cells. It lowers the blood glucose concentration if it has become too high. This can happen after eating a meal that is rich in carbohydrates (for example, sweets, potatoes, bread, rice or pasta). The pictures show how this works. Diabetes Diabetes is a disease where the concentration of  glucose  in the blood is not controlled properly by the body.In  type 1 diabetes, the  pancreas  does not produce eno-ugh  insulin. This can lead to high levels of glucose in the blood, which can be fatal. Types of Diabetes There are two types of treatment for diabetes: * Careful monitoring of food intake, with particular care taken over carbohydrates – which are digested into glucose. * Injecting insulin into the blood before meals. The extra insulin causes glucose to be taken up by th e liver and other tissues. Cells get the glucose they need for respiration, and the blood glucose concentration stays normal. Temperature regulation Human  enzymes  work best at 37?C, so the body’s temperature is controlled. A part of the brain called the  thermoregulatory centre  monitors and controls body temperature. It gathers information as nerve impulses from  temperature receptors  in: * the brain – these are sensitive to the temperature of the blood flowing there * the skin – these are sensitive to skin temperature Sweating Sweating is one way to help cool the body. We sweat more in hot conditions, so more water is lost from the body. This water must be replaced through food or drink to maintain the balance of water in the body. Ions such as sodium ions and chloride ions are also lost when we sweat.They must be replaced through food and drink. If the body’s ion content is wrong, cells can be damaged. Temperature regulation – hig her If you become too hot or too cold, there are several ways in which your temperature can be controlled. They involve sweating, shivering, skin capillaries and hairs. Too hot When we get too hot: * Sweat glands in the skin release more sweat. This evaporates, removing heat energy from the skin. * Blood vessels leading to the skin capillaries become wider – they  dilate  Ã¢â‚¬â€œ allowing more blood to flow through the skin, and more heat to be lost. Too cold When we get too cold: * Muscles contract rapidly – we shiver.These contractions need energy from respiration, and some of this is released as heat. * Blood vessels leading to the skin capillaries become narrower – they  constrict- letting less blood flow through the skin and conserving heat in the body. The hairs on the skin also help to control body temperature. They lie flat when we are warm, and rise when we are cold. The hairs trap a layer of air above the skin, which helps to insulate the skin a gainst heat loss. Controlling temperature Too cold| Too hot| | | A  Ã¢â‚¬â€œ Hair muscles pull hairs on end. B  Ã¢â‚¬â€œ Erect hairs trap air. C  Ã¢â‚¬â€œ Blood flow in capillaries decreases. | D  Ã¢â‚¬â€œ Hair muscles relax.Hairs lie flat so heat can escape. E  Ã¢â‚¬â€œ Sweat secreted by sweat glands. Cools skin by evaporation. F  Ã¢â‚¬â€œ Blood flow in capillaries increases. | Remember: Capillaries do not move up and down inside the skin. Temperature is regulated by controlling the amount of blood which flows through the capillaries. Hormones Hormones are chemical substances that help to regulate processes in the body. Hormones are secreted by glands and travel to their target organs in the bloodstream. Several hormones are involved in the female menstrual cycle. Hormones can be used to control human fertility and have advantages and disadvantages. Hormones and glandsHormones are  chemicals secreted by glands  in the body. Different hormones affect different target organs. The bloodstream transports hormones from the glands to the target organs. Hormones regulate the functions of many cells and organs The target organ and effects of glands and hormones Gland| Hormone| Target organs| Effect| adrenal gland| adrenalin| vital organs, e. g. liver and heart| Prepares body for action – ‘fight or flight'. | ovary| oestrogen| ovaries, uterus, pituitary gland| Controls puberty and the menstrual cycle in females; stimulates production of LH and suppresses the production of FSH in the pituitary gland. ovary| progesterone| uterus| Maintains the lining of the womb – suppresses FSH production in the pituitary gland. | pancreas| insulin| liver| Controls blood sugar levels. | pituitary gland| anti-diuretic hormone (ADH)| kidney| Controls blood water level by triggering uptake of water in kidneys. | pituitary gland| follicle stimulating hormone (FSH)| ovaries| Triggers egg ripening and oestrogen production in ovaries. | pituitary gland| lut einising hormone (LH)| ovaries| Triggers egg release and progesterone production in ovaries. | testes| testosterone| male reproductive organs| Controls puberty in males. |Hormones in the menstrual cycle The menstrual cycle in women is a recurring process in which the lining of the uterus – womb – is prepared for pregnancy, and if pregnancy does not happen, the lining is shed at menstruation. Several  hormones  control this cycle, which includes controlling the release of an egg each month from an ovary, and changing the thickness of the uterus lining. These hormones are secreted by the ovaries and pituitary gland. FSH The hormone FSH is secreted by the pituitary gland. FSH makes two things happen: 1. it causes an egg to mature in an ovary 2. it stimulates the ovaries to release the hormone oestrogen OestrogenThe hormone oestrogen is secreted by the ovaries. Oestrogen makes two things happen: 1. it stops FSH being produced – so that only one egg matures in a cycle 2. it stimulates the pituitary gland to release the hormone LH LH The hormone LH causes the mature egg to be released from the ovary. This image shows how the level of oestrogen changes during the menstrual cycle. Progesterone is another hormone secreted by ovaries: it maintains the lining of the uterus and stays high during pregnancy. Hormone levels during the menstrual cycle Controlling fertility Human fertility is controlled by  hormones.This means that knowledge of hormones can be used to decide to increase, or reduce, the chances of fertilisation and pregnancy. Oral contraceptives Contraceptive pills The oral contraceptive, ‘the pill', greatly reduces the chances of mature eggs being produced. The pill contains oestrogen, or oestrogen and progesterone. These hormones inhibit the production of FSH, which in turn stops eggs maturing in the ovaries. Fertility treatment Some women have difficulty becoming pregnant because they don't produce enough FSH to allow their e ggs to mature. ‘Fertility drugs' contain FSH, which stimulates eggs to mature in the ovary. The nervous systemThe nervous system allows the body to respond to changes in the environment. This is a process usually coordinated by the brain. Reflex actions are extra-rapid responses to  stimuli, and this process also involves the nervous system, but bypasses the brain. Receptors and effectors Receptors Receptors are groups of specialised cells. They can detect changes in the environment, which are called  stimuli, and turn them into electrical impulses. Receptors are often located in the  sense organs, such as the ear, eye and skin. Each organ has receptors sensitive to particular kinds of stimulus. Receptors sense organs| receptors sensitive to|Skin| touch, pressure, pain and temperature| Tongue| chemicals in food| Nose| chemicals in the air| Eyes| light| Ears| sound and position of the head| The central nervous system – CNS – in humans consists of the brain a nd spinal cord. When a receptor is stimulated, it sends a signal along the nerve cells – neurones – to the brain. The brain, then co-ordinates the response. Effectors An effector is any part of the body that produces the response. Here are some examples of effectors: * a muscle contracting to move the arm * a muscle squeezing saliva from the salivary gland * a gland releasing a  hormone  into the blood NeuronesNeurones are nerve cells. They carry information as tiny electrical signals. There are  three different types of neurones, each with a slightly different function. 1. Sensory neurons  carry signals from  receptors  to the spinal cord and brain. 2. Relay neurons  carry messages from one part of the  CNS  to another. 3. Motor neurons  carry signals from the  CNS  to effectors. The diagram below shows a typical neuron – in this case, a motor neuron. It has tiny branches at each end and a long fibre carries the signals. A motor neuron S ynapses Where two neurones meet, there is a tiny gap called a synapse. Signals cross this gap using chemicals.One neurone releases the chemical into the gap. The chemical diffuses across the gap and makes the next neurone transmit an electrical signal. Reflex actions When a receptor is stimulated, it  sends a signal to the central nervous system, where the brain co-ordinates the response. But sometimes  a very quick response is needed, one that does not need the involvement of the brain. This is a reflex action. Reflex actions are rapid and happen without us thinking. For example, you would pull your hand away from a hot flame without thinking about it. The animation below allows you to step through each stage of the reflex arc.This is what happens: 1. receptor detects a stimulus – change in the environment 2. sensory neurone sends signal to relay neurone 3. motor neurone sends signal to effector 4. effector produces a response The way the iris in our eye adjusts the size of the pupil in response to bright or dim light is also a reflex action. In  bright  light: * Radial muscles of the iris relax. * Circular muscles of the iris contract. * Less light enters the eye through the contracted pupil. In  dim  light: * Radial muscles of the iris contract. * Circular muscles of the iris relax. * More light enters the eye through the dilated pupil.Defending against infection Pathogens are microorganisms – such as bacteria and viruses – that cause disease. Bacteria release toxins, and viruses damage our cells. White blood cells can ingest and destroy pathogens. They can produce antibodies to destroy pathogens, and antitoxins to neutralize toxins. In vaccination pathogens are introduced into the body in a weakened form. The process causes the body to produce enough white blood cells to protect itself against the pathogens, while not getting diseased. Antibiotics are effective against bacteria, but not against viruses. Some strains of bact eria are resistant to antibiotics.Pathogens – bacteria Pathogens are  microorganisms  that cause infectious disease. Bacteria and viruses are the main pathogens. Bacteria Bacteria are  microscopic organ-isms. They come in many shapes and sizes, but even the largest are only 10 micrometres long – 10 millionths of a metre. Bacteria are  living cells  and, in favourable conditions, can multiply rapidly. Once inside the body, they release poisons or toxins that make us feel ill. Diseases caused by bacteria include:- -food poisoning -cholera -typhoid -whooping cough -gonorrhoea – a sexually transmitted disease Pathogens – viruses Viruses are many times smaller than  bacteria.They are among the smallest organisms known and consist of a fragment of genetic material inside a protective protein coat. Viruses can only reproduce  inside host cells, and they damage the cell when they do this. A virus can get inside a cell and, once there, take over and make hundreds of thousands of copies of itself. Eventually the virus copies fill the whole host cell and burst it open. The viruses are then passed out in the bloodstream, the airways, or by other routes. Diseases caused by viruses include: * influenza – flu * colds * measles * mumps * rubella * chicken pox * AIDS White blood cellsThe body has different ways of protecting itself against  pathogens. The first defence is passive immunity. This is aimed at stopping the pathogen getting into the body in the first place. The body’s passive immunity system includes the skin,  mucus  and  cilia  in the respiratory system, acid in the stomach, and enzymes  in tears. If a pathogen still manages to get into the body, the second defence takes over. This is called  active immunity, and the white blood cells have key functions in this. Functions of the white blood cells White blood cells can: * ingest pathogens and destroy them * produce antibodies to destroy pathogen s produce antitoxins that neutralise the toxins released by pathogens In a written examination, it is easy to get carried away and waffle on about things such as invaders and battles, but stick to the point. Note that: * the pathogens are not the disease – they cause the disease * white blood cells do not eat the pathogens – they ingest them * antibodies and antitoxins are not living things – they are specialised proteins More about white blood cells There are several different types of white blood cells, each with different functions, but they can be put into two main groups: * phagocytes or macrophages lymphocytes Phagocytes Phagocytes can easily pass through blood vessel walls into the surrounding tissue and move towards  pathogens  or   toxins. They then either: * ingest and absorb the pathogens or toxins * release an enzyme to destroy them Having absorbed a pathogen, the phagocytes may also send out chemical messages that help nearby lymphocytes to id entify the type of antibody needed to neutralise them. Lymphocytes Pathogens contain certain chemicals that are foreign to the body and are called antigens. Each lymphocyte carries a specific type of antibody – a protein that has a chemical ‘fit' to a certain antigen.When a lymphocyte with the appropriate antibody meets the antigen, the lymphocyte reproduces quickly, and makes many copies of the antibody that neutralises the pathogen. Antibodies neutralise pathogens in a number of ways: * they bind to pathogens and damage or destroy them * they coat pathogens, clumping them together so that they are easily ingested by phagocytes * they bind to the pathogens and release chemical signals to attract more phagocytes Lymphocytes may also release antitoxins that stick to the appropriate toxin and stop it damaging the body. Vaccination People can be immunised against a pathogen through vaccination.Different vaccines are needed for diffe-rent  pathogens. Vaccination involves putting a small amount of an inactive form of a pathogen, or dead pathogen, into the body. Vaccines can contain: * live pathogens treated to make them harmless * harmless fragments of the pathogen * toxins  produced by pathogens * dead pathogens These all act as antigens. When injected into the body, they stimulate white blood cells to produce antibodies against the pathogen. Because the vaccine contains only a weakened or harmless version of a pathogen, the vaccinated person is not in danger of developing disease – although some people may uffer a mild reaction. If the person does get infected by the pathogen later, the required lymphocytes are able to reproduce rapidly and destroy it. Vaccines and boosters Vaccines in early childhood can give protection against many serious diseases. Sometimes more than one vaccine is given at a time, like the MMR triple vaccine against mumps, measles and rubella. Sometimes vaccine boosters are needed, because the immune response ‘m emory' weakens over time. Anti-tetanus injections may need to be repeated every ten years. Antibiotics Antibiotics are substances that kill  bacteria  or stop their growth.They do not work against  viruses: it is difficult to develop drugs that kill viruses without also damaging the body’s tissues. How some common antibiotics work antibiotic| how it works| penicillin| breaks down cell walls| erythromycin| stops protein synthesis| neomycin| stops protein synthesis| vancomycin| stops protein synthesis| ciprofloxacin| stops DNA replication| Penicillin The first antibiotic – penicillin – was discovered in 1928 by Alexander Fleming. He noticed that some bacteria he had left in a petri dish had been killed by naturally occurring penicillium mould.Since the discovery of penicillin, many other antibiotics have been discovered or developed. Most antibiotics used in medicine have been altered chemically to make them more effective and safer for humans. Resistance Ba cterial strains can develop resistance to antibiotics. This happens because of natural selection. In a large population of  bacteria, there may be some cells that are not affected by the antibiotic. These cells survive and reproduce, producing even more bacteria that are not affected by the antibiotic. MRSA is methicillin-resistant staphylococcus aureus.It is very dangerous because it is resistant to most antibiotics. It is important to avoid over-use of antibiotics, so we can slow down, or stop, the development of other strains of resistant bacteria. Cleanliness One simple way to reduce the risk of infection is to maintain personal hygiene and to keep hospitals clean. Diet and Exercise Regular exercise and a balanced diet are needed to keep the body healthy. Too little food leads to a person being underweight and prone to illness, while too much food and not enough exercise leads to a person being overweight and prone to other illnesses.Excess cholesterol increases the risk of he art disease, and excess salt causes high blood pressure and increases the risk of heart disease and stroke. Nutrients A mixture of different types of food in the correct amounts is needed to maintain health. The main food groups are: The main food groups food group| found in| required by our bodies for| | potatoes, pasta, bread, bananas, sugar and rice| A source of  energy  for other life processes. Sometimes referred to as  fibre, which is actually just one – very common – type of carbohydrate. | | cheese, butter, margarine and oils| Fats are needed to make cell membranes and to  insulate  our bodies.They also contain important fat-soluble  vitamins. | | meat, fish, eggs and cheese| Growth and repair. | | whole meal bread, fruit, vegetables and pulses| The fibre or roughage in our diet is not digested, but is important because it allows the muscles in our intestines to move food through our system by  peristalsis. | Metabolic rate A healthy diet contains all the different nutrients in the correct amounts, and provides the right amount of energy for each individual. An unbalanced diet can lead to a person becoming malnourished. They may be too thin or too fat as a result, and they may suffer from deficiency diseases.Chemical reactions Respiration is the chemical reaction that allows cells to release energy from food. The metabolic rate is the speed at which such chemical reactions take place in the body. It varies because of several factors, including: * age * gender – male or female * the proportion of muscle to fat in the body * the amount of exercise and other physical activity * genetic traits The metabolic rate increases as we exercise and stays high for a while afterwards. The right amount of food Not enough food If you don't eat enough food, you will become too thin and may suffer from health problems.These include: * irregular periods in women * reduced resistance to infection * deficiency diseases Deficiency diseases include  rickets  Ã¢â‚¬â€œ which affects proper growth of the skeleton and is caused by insufficient vitamin D – and  kwashiorkor  Ã¢â‚¬â€œ which causes a swollen abdomen and is a result of insufficient protein. Problems such as these are more likely to affect people in the developing world, where it can be more difficult to get enough food. Too much food In warm weather, or when you don't do much exercise, you do not need to eat as much food as when it is cold or when you have exerted yourself physically.If you eat too much food without taking enough exercise, you will become overweight. Very fat people are described as  obese. Overweight people may suffer from health problems, including: * diabetes  Ã¢â‚¬â€œ an illness in which the body is unable to control the amount of sugar in the blood * arthritis  Ã¢â‚¬â€œ an illness in which the joints become worn, inflamed and painful * high blood pressure * heart disease The heart The heart is an organ that needs its own supply of blood to keep it working. If the blood supply is reduced, the heart muscle will not work properly and will become weaker.A heart attack happens when part of the heart does not get any blood because of a blocked artery. Cholesterol Cholesterol is a substance found in the blood. It is made in the liver and is needed for healthy cell membranes. However, too much cholesterol in the blood increases the risk of heart disease, and of diseased arteries. Good and bad cholesterol The bloodstream transports cholesterol around the body attached to  proteins. The combination of cholesterol and protein is called  lipoprotein, and there are two types. 1. Low-density lipoproteins  Ã¢â‚¬â€œ LDLs – carry cholesterol from the liver to the cells. 2.High-density lipoproteins  Ã¢â‚¬â€œ HDLs – carry excess cholesterol back to the liver. LDLs are often called ‘bad' cholesterol because they lead to fat building up on artery walls, which causes heart disease. HDLs ar e often called ‘good’ cholesterol because they help to stop fat building up in the arteries. Improving the balance A high proportion of HDLs to LDLs is good for a healthy heart. Monounsaturated and polyunsaturated oils – as found in vegetable oils – help to reduce cholesterol levels in the blood, and also increase the proportion of HDLs compared with LDLs. Check your understanding of such oils by looking at  Vegetable oils.There are also drugs that can improve high blood pressure and high cholesterol levels. Salt Table salt is sodium chloride. Too much salt in the diet can lead to  high blood pressure, which in turn leads to an increased risk of heart disease and strokes. Salt is  found naturally in many kinds of food, but more is added by food manufacturers – and many people add even more when they are eating. Processed foods often have a high proportion of salt and fat. Salt added to food during processing accounts for about two-thirds of th e average salt intake. Adaptation Adaptations – cold climatesEvery organism has certain features or characteristics that allow it to live successfully in its  habitat. These features are called adaptations, and we say that the organism is adapted to its habitat. Organisms living in different habitats need different adaptations. The polar bear Polar bears are well adapted for survival in the Arctic. They have: * a white appearance, as camouflage from prey on the snow and ice * thick layers of fat and fur, for insulation against the cold * a small surface area to volume ratio, to minimise heat loss * a greasy coat, which sheds water after swimmingThe snowshoe hare The snowshoe hare has white fur in the winter and reddish-brown fur in the summer. This means that it is camouflaged from its  predators  for most of the year. Arctic plants The Arctic is cold and windy with very little rainfall. Plants in the Arctic often grow very close to the ground and have small leaves. Thi s helps to conserve water and to avoid damage by the wind. Adaptations – hot climates The camel Camels live in deserts that are hot and dry during the day, but cold at night. They are well adapted for survival in the desert.Camels have: * Large, flat feet  to spread their weight on the sand. * Thick fur  on the top of the body for shade, and thin fur elsewhere to allow easy heat loss. * A large surface area to volume ratio  to maximise heat loss. * The  ability to go for a long time without water  (they don't store water in their humps, but they lose very little through urination and sweating). * The ability to  tolerate body temperaturesup to 42 °C. * Slit-like nostrils and two rows of eyelashesto help keep the sand out. Desert plants Cacti are well adapted for survival in the desert. They have: * Stems that can store water. Widespread root systems that can collect water from a large area. In addition,  cacti have spines instead of leaves. These minimise the surface area and so reduce water loss by  transpiration. The spines also protect the cacti from animals that might eat them. Other adaptations Animals and plants may have specific features that adapt them to their environment. These include barbs and spines, poisons and warning colours that deter predators and herbivores. Some harmless species may even resemble a poisonous or dangerous species to increase their chances of survival. Characteristics and classificationGenetic information from one species can be transferred to another species using genetic engineering. Selective breeding, also called artificial selection, involves people taking charge of selection to produce new varieties of various species. A variety is a type of a particular species that is different in some clear way from other varieties of that species. The characteristics of a species can be used to classify the species. This is sometimes difficult to do. Genetic engineering Genetic engineering is also called gen etic modification (or  GM). It is not the same as cloning.Although cloning techniques are used in genetic engineering, the two things should not be confused. The table shows some of the differences. Cloning| Genetic engineering| Produces exact copies. | Produces a unique set of genes. | Genes copied within the same species. | Genes can be swapped across species. | Selective breeding Natural selection Species gradually evolve by a process of natural selection. The individuals in any population with the inherited features best suited to the environment in which they live are most likely to survive and reproduce. When they do, they pass on the genetic information for these features to their offspring.Over time, a species can change its appearance and may even become a new species, unable to reproduce successfully with individuals of the original species. Artificial selection Selective breeding, also called artificial selection, involves people taking charge of selection to produce ne w ‘varieties' of various species. A variety is a type of a particular species that is different in some clear way from other varieties of that species. For example, pedigree dogs come in lots of different varieties (or breeds) – they may be different colours and sizes, but they are all still dogs.Suppose you wanted a variety of cow that produced a lot of milk. This is what you could do: * choose or select the cows in your herd that produce the most milk * only let these cows reproduce * select the offspring that produce the most milk * only let these offspring reproduce * keep repeating the process of selection and breeding until you achieve your goal The key here is to identify the feature you want, and only breed from the individuals that have that feature. Here are some examples of what selective breeding can produce: * hens that lay big eggs of a particular colour cattle that produce lots of meat * tomato plants that produce lots of tomatoes * crops that are resista nt to certain plant diseases Changing the characteristics of a species The characteristics of a species can be changed by: * natural selection * selective breeding * genetic engineering. The table shows some differences between these. | Natural selection| Selective breeding| Genetic engineering| Number of generations needed for change| very many| many| one| Human intervention| not needed| needed| needed| Desired outcome known? | no| yes| yes| New species formed? | yes| no| no|Notes| This is the mechanism of change in Darwin's theory of evolution| This is how new varieties or breeds are usually produced| Genetic information can come from the same species or from a different one| In selective breeding and genetic engineering, there is a goal or desired outcome. For example, we may wish to produce a variety of cow capable of producing a lot of milk, or a bacterium capable of producing insulin. There is no goal in natural selection: although we find that particular species are well adap ted to their environments, natural selection does not ‘know' what the species should be like.Individuals that are better suited to their environment are more likely to survive to reproduce, and so pass on their characteristics to the next generation, than those that are poorly suited. Classification You will remember from your Key Stage 3 studies that species with similar characteristics are put into groups, and that this is called classification. Remind yourself of the basics of classification by looking  here. Kingdoms The first rank in this system is called a kingdom. There are five kingdoms, based upon what an organism's cells are like: 1. nimals (all multicellular animals) 2. plants (all green plants) 3. fungi (moulds, mushrooms, yeast) 4. prokaryotes (bacteria, blue-green algae) 5. protoctists (Amoeba, Paramecium) Further divisions There are several further ranks before we reach a particular species. In order, these are: * kingdom * phylum * class * order * family * ge nus * species For example,  lions  have the following classification: * kingdom – animal * phylum – vertebrate * class – mammal * order – carniverous * family – cat * genus – big cat * species – lion Difficulties with classificationIt can be  easy  to classify a species. For example, we are  Homo sapiens. Classification of species rank| classification| notes| kingdom| animals|   | phylum| chordates| animals with backbones| class| mammals| animals that are warm-blooded, have lungs and body hair, produce milk and give birth to live young| order| primates| ape-like animals| family| hominids| human-like animals| genus| homo| humans| species| sapiens| modern humans| It can also be  difficult  to classify a certain organism. For example, the single-celled organism called Euglena has some confusing characteristics.It has: * chloroplasts, like a plant * no cell wall, like an animal * a flagellum to swim with, like some bacteri a A fifth kingdom, called the protoctists, was made for organisms like Euglena. The Heart The heart requires its own constant blood supply in order to keep beating and this is delivered through the coronary arteries. Genetic and lifestyle factors can lead to the coronary arteries becoming blocked, and an increased risk of heart disease. The circulatory system Blood carries oxygen and nutrients to the body’s  cells, and waste products away from them.The circulatory system consists of: * the heart, which is the muscular pump that keeps the blood moving * the arteries, which carry blood away from the heart * the veins, which return blood to the heart * the capillaries, which are tiny blood vessels that are close to the body’s cells The diagram outlines the circu-latory system. To make things clear, oxygenated blood is shown in red, and deoxygenated blood in blue. Arteries and veins The arteries carry blood from the heart, while veins return blood to it. With both, their structure is related to their function. ArteriesBlood in the arteries is under high pressure generated by the heart. The arteries have: * thick outer walls * thick layers of muscle and elastic fibres Veins The blood in veins is under lower pressure than the blood in arteries. The veins have: * thin walls * thin layers of muscle and elastic fibres Unlike arteries, veins have one-way valves in them to keep the blood moving in the correct direction. The heart The heart is a muscular organ. It keeps beating at about 70 times per minute. You can see how it pumps the blood to the lungs and the rest of the body by studying this animation.The muscle cells in the heart need a constant supply of oxygen and nutrients, and for their waste products to be removed. So the heart requires its own blood supply in order to keep beating. Blood vessels called the  coronary arteries  supply blood to the heart muscles. If they become blocked, a  heart attack  can happen. Heart attacks A heart att ack can happen because: 1. Fatty deposits build up in the coronary arteries. 2. A blood clot can form on a fatty deposit. 3. The blood clot can block a coronary artery. 4. Some heart muscle cells do not get the oxygen and nutrients they need. 5. These cells start to die.Causes of heart disease Heart disease is not usually caused by micro-organisms. It is caused by: * genetic factors, which show as a family history of heart disease * lifestyle factors Heart disease is more common in the UK than in non-industrialised countries, and many other indust-rialised nations. This is due to lifestyle factors  including: * smoking * lack of regular exercise * stress leading to a fast heart rate * drinking a lot of alcohol * poor diet A lack of exercise and a diet that is high in salt and saturated fat cause people to: * become overweight * have high blood pressure have high levels of cholesterol in their blood These factors contribute to an increased risk of heart disease. Extra Sex hormones Changes occur at puberty because of sex hormones produced by the testes in boys, and the ovaries in girls. Some changes happen to everyone, both boys and girls, while others happen in one sex only. Here are some changes that happen to both boys and girls: * pubic hair grows * underarm hair grows Here are some changes that happen to boys only: * voice breaks – gets deeper * hair grows on face and body * body becomes more muscular * testes and penis get bigger testes start to produce sperm cells Here are some changes that happen to girls only: * hips get wider * breasts develop * ovaries start to release egg cells – periods start Fertility in humans can be controlled by the artificial use of sex hormones, including contraceptive pills and fertility drugs. Competition Different species compete to survive and breed. The size of a predator population depends on the size of the prey population, and the reverse is true as well. Mutualism benefits both species involved in the relationship, but parasitism only benefits the parasite, not the host.Habitats have limited amounts of the resources needed by living organisms. Organisms must  compete  with others in order to get enough of these resources to survive. If they are unsuccessful and cannot move to another habitat, they will die. Animals Some of the resources that animals compete for: * food * water * space Animals may also compete for mates so that they can reproduce. Plants Remember that plants make their own food using  photo-synthesis, so they do not compete for food. Here are some of the things that plants do compete for: * light * water space * mineral salts Human beings Human beings are very successful organisms. We compete with animals for food resources, and we compete with both animals and plants for space and water. The nitrogen cycle Seventy-nine per cent of the air around us is nitrogen. Living things need nitrogen to make proteins, but they cannot get it directly from the air becaus e nitrogen gas is too  unreactive  to be used to make new compounds within an organism. Plants can take up and use nitrogen when it is in a more  reactive  form – for example, in  nitrates  or  ammonium salts.Changing nitrogen into a more reactive substance is called  nitrogen fixation. Nitrogen fixation Nitrogen fixation happens in three different ways: The energy in a lightning bolt can split nitrogen molecules in the air, allowing each nitrogen atom to  react  with oxygen to form  nitrogen oxides. The rain washes these oxides to the ground, where they form  nitrates. * The Haber Process  is used by industry to produce ammonia from nitrogen. Ammonia is then used to make the fertiliser that farmers spread on the soil to feed their crops. Nitrogen-fixing bacteria found in both the soil and root nodules of leguminous plants fix nitrogen into a form that can be used by plants. When plants are eaten by animals, the nitrogen compounds are passed on. Nitr ogen compounds are returned to the soil by excretion and egestion from animals, or when plants and animals die and decay. The nitrogen compounds returned in this way are  changed back  to nitrogen gas by denitrifying bacteria which live in the soil. This  completes the cycle, so that the percentage of nitrogen in the air remains constant. The nitrogen cycle

Speaker Observation Paper

On Monday April 18th the Dublin Library, in celebration of Earth Day, hosted environmental educator, activist, and author Dr. Linda Riebel. In her presentation she introduced the new edition of her book; The Earth Friendly Food Chain under the new title; The Green Foodprint. Her topic was on food choices for healthy people and a healthy planet. The purpose of her speech was to show how anyone-of any lifestyle-can become an earth friendly eater. The presentation was held in a small room in the Library and the audience turnout was surprisingly minimal. There were a total of four adults that attended. Despite the partially empty room, the speaker was able captivate the audience instantly by opening with a personal experience story about how a Safari trip to Africa ultimately changed her life and as a result she became vegetarian. Dr. Riebel began her speech by proclaiming, with enthusiasm, that the â€Å"Food Movement† has started. In the introduction of her speech she reveals her credibility on the subject. Dr. Linda Riebel is not only a vegetarian, but she also is a Psychologist, Eating Disorder Specialist, and Author of the acclaimed book, Eating to Save the Earth: Food Choices for a Healing Planet. She emphasizes that her speech would not dwell on the bad and negative but rather, focus on the solutions. The solution, she previewed, is already in movement; organic food, local food, meatless options and family farms. At her conclusion she reaffirms that what’s good for the planet and it’s creatures is also good for humans. She concludes by reiterating the good and positive, in that people are moving in the right direction. To further her message, she left the audience with information on where to find local farms, stores, restaurants, and more, for healthy sustainable foods. She pointed out the benefit of having a diverse system of agriculture that takes advantage of our local area's resources, tradition, and taste. Also, she was proud to announce that the City of Dublin is launching a new seasonal farmers' market beginning May 12. In addition to having the freshest in California-grown produce, she states, it will have different â€Å"theme weeks† every month to showcase a variety of the local talent and attractions. In her speech, Dr. Riebel, pointed out that; just as we have a carbon footprint, we also have a â€Å"foodprint â€Å"as well. Our â€Å"foodprint†, she explained, is the way in which our food system's contribute to greenhouse gas emissions and global climate change through the production, processing, packaging, shipping, storage and disposal of food. First she explains some of the environmental problems we are facing right now. This included some information on how we are depleting our water. A vast underground reserve called the Ogallala Aquifer supports over one-fifth of the irrigated cropland in the United States and in the last forty years, farmers have pumped massive amounts of water from the aquifer. While the need for water continues to grow, the amount available decreases rapidly. In some areas, farmers are consuming the groundwater at more than twice the rate of natural recharge. She also talks about the agricultural use of some rainforest land and how this habitat destruction affects wildlife today. Many commercial agricultural projects are still carried out on rainforest lands, although many of these revert to cattle pasture after soils are depleted. She also made it a point to discuss pesticides. She began this topic with an interesting history of the original use of pesticides. Their mass introduction into farming 70 years ago, along with petrochemically-derived fertilizers, set U. S. farming down a costly and unsustainable path. Along the way, community-scale farming was nearly destroyed, generations have suffered ill health ranging from cancer to autism and Parkinson’s, biodiversity has taken big hits, and the six mega-corporations who dominate the pesticide industry have gotten very rich and very powerful. She speaks of hope in that an organization called PAN( Pesticide Action Network) promotes the elimination of highly hazardous pesticides and offers solutions that protect people and the environment. PAN works to loosen the pesticide industry’s control over global agriculture by holding accountable governmental bodies that are charged with regulating pesticides. Dr. Riebel used a PowerPoint as her presentational aid. The PowerPoint presentation had appropriate graphics, appropriate font for ease of reading, appropriate layout of graphics and graphics were in good taste. The slides were very informative and did not take away from the overall presentation. She included pictures and quotes that got my attention. She also used her new book The Green Foodprint to refer to many of her points. This made me want to buy her book to learn more. She did a good job of relating the topic to current issues of today. The fact that she gave her speech in honor of Earth Day showed how she was trying to adapt her speech to this occasion. She was able to present her message with facts and information in a language that was easily understandable for the audience. She explained unfamiliar terms and concepts and was able to relate her message to the audience by enticing questions and answers from them. Her speech was enlightening and somewhat of a shock, considering some of the surprising facts she stated. The audience responded with awareness and interest. The speaker did a great job with her delivery. She had confidence and poise. She used specific topics that had relevant value, she maintained accuracy in her statements, and she provided additional clarifying material. Her poise was shown by her controlled voice. The volume in her voice was loud enough to be comfortably heard. Her use of power, pace and pitch was appropriate for the emotion or thought she was trying to express. For example, when she was trying to entice empathy from the audience when discussing the inhumane treatment of animals, she spoke slowly, and with compassion. She expressed a more enthusiastic delivery, specifically when she talked about the solutions such as shopping local and going organic. Her use of enthusiasm was appropriate to motivate and persuade the audience to make a change. She was able to stress important words such as â€Å"Foodprint† and â€Å"Organic† when presenting principal ideas. She maintained a technique of proper pausing to punctuate, to change thought or for emphasis. Her personal appearance showed proper attire and grooming. She had proper posture by standing straight and not fidgeting her hands. She did not show inappropriate facial expressions and was able to maintain eye contact with audience by directly addressing them. She exerted a warmth feeling, manifested in her facial expression and tone of voice. She had a conversational delivery which she utilized conversational expressions. She used her body to make descriptive gestures and emphatic gestures. This delivery was very effective because the audience was included. She successfully came across as well informed and educated on the topic. The urgency in her voice enticed the idea of change, especially in relation to the concept of Earth Day, and all the people in support of maintaining a healthy planet while eating healthy. Overall, I enjoyed this speech greatly. The speaker was very organized and confident in what she was saying. The urgency in her tone made me want to be part in the movement to creating a healthier planet and food. The delivery was very effective and it gave me a greater awareness about the food I eat and where it comes from and what’s in it. As she first stated in the beginning of the speech, that she would focus on the positive , she was successful in creating awareness of the solutions all around us.

Caligua Roman Empire Research Paper Example | Topics and Well Written Essays - 1000 words

Caligua Roman Empire - Research Paper Example By that time Caligula’s father was dead and his mother and two brothers were in disgrace. At Capri, Caligula was appointed as heir together with Tiberius Gemellus, son of Drusus the younger. According to the Roman law, Caligula did not have a right to be the emperor, but nevertheless it happened. After the death of Tiberius, with the help of Macro, Caligula was proclaimed â€Å"princeps† (first citizen) by the Senate. Tiberius’s will was invalidated and Caligula was proclaimed emperor with the official name of Gaius Caesar Augustus Germanicus in AD 37. The people of the empire were happy with the news, because Caligula’s parents were very popular in Rome and loved and respected by people. The first actions of the new emperor were directed at gaining popularity. When he entered Rome, he put Tiberius body into Augustus’ mausoleum, and made a funeral speech, in which he promised to rule Roman Empire together with the Senate and under its supervision. C aligula dropped a request for the deification of Tiberius, who was very unpopular in Rome, and announced amnesty. He put the taxes down and paid all the debts made by previous emperor. The new emperor won over the masses by resuming gladiator fights, bringing back actors from exile, and renewing of theatrical performances. Of course, such politics was very popular among the people. At this festive background, amplification of the monarchical principle and exaltation of power and personality of the emperor occurred. Caligula made a visit to Pandateriya and Pontius, and moved the ashes of his mother Agrippina and his brother Nero to Rome. There were yearly sacrifices yielded in honor of Germanicus and Agrippina, and circus games were arranged in honor of his mother. There were a lot of coins depicting the princeps’ brothers and parents. In six months Caligula got seriously sick. After his recovery he was no longer the same person. Some of the historians say that he had epilepsy from his childhood. †This, or some other cause, violently affected his mental state, and he became totally irrational, with delusions not only of grandeur but also of divinity.† (http://www.roman-empire.net/emperors/caligula.html, para.15). Caligula’s policy has changed so much that there was a firmly established belief in the society about his madness. It could be seen through his actions (for example, he was going to make his horse a consul) and in his appearance. The issue of mental normality of Gaius Caligula has occupied many researchers’ minds, both historians and psychologists. The opinions were divided. Some scholars have regarded him as mentally ill, while others believed that he was mentally normal. The range of definitions of his disease varies from schizophrenia to psychopathy. The latter version is the most recognized by modern scholars and seems the most convincing. In AD 38 Caligula put to death without trial his principal supporter, the pra etorian prefect Macro. Gemellus was also killed by his order. Marcus Junius Silanus, the father of the first of Caligula's wives was compelled to commit suicide. A new feature was that the process did not occur in the Senate: princeps alone decided the fate of the eminent dignitaries of the empire. In a short period of one year Caligula wasted all of the reserves of the state treasury accumulated by the Tiberius. New taxes were introduced to

Employee Reward (Executive Reward) Essay Example | Topics and Well Written Essays - 2750 words

Employee Reward (Executive Reward) - Essay Example The executive compensation system helps in the improvement of the existing system that helps in accomplishment of goals and objectives. A well structured compensation system helps in the attraction of dynamic and talented pool of executives who can help the company in gaining competitive advantage over its competitors (Browning, 2012).An integrated approach of designing a reward structure helps in developing a system which is directly related to the growth of the company . Executive reward system in a company is the result of a high level interaction between the company executives and the director to maintain an acceptable return on the investment at all times. The executives expect some kind of salary based on daily or annual basis. It also includes employment contracts, portable retirement benefits and deferred compensation (Haygroup, 2013). The company management instead wishes that the executive achieve specific goals and also include developing capabilities (Edge and Davis, 2004 ). A well constructed EC system is only feasible with the development of a leadership framework in which the responsibilities, duties and capabilities are clearly identified and sorted out as per the executive level. In the leadership framework the level, responsibility, capability and results are clearly defined which helps in identification of the opportunities and the development of a strategy. The traditional executive compensation system was developed by Mirrlees and Holmstrom in the year 1975 and later it was modified by Holmstrom and Tirole in the year 1993 (Haygroup, 2013). This theory was developed to help in building an incentive scheme which focuses on trade-off risk sharing and incentive, reward consideration. The theory was also formulated keeping in mind whether the management would be able to pay back the invested amount or not. The author laid emphasis on the fact that stock prices not only reflected the fundamental value of the organization but also signified a shor t term speculative amount. The various constituents of the executive reward systems are as follows: Direct Pay Base Salary The entire executive system would include the annual based salary which would be replaced by the executive salary plans. As per the leadership framework the executive total rewards system would be as follows. Base Salary Annual Incentives and Perks Long Term Incentives Career Development Responsibilities Short Term Success Long Term Success The capability and short term success would be considered The executive salary planning would start as per the market pay data and the desired competitive range would be decided based on the competitive performance of the executives. It also includes the inputs and growth in individual responsibility and the high level performance for the individual (Armstrong, 2002). The salary plans are developed on the assumption of the consistent performance for the executive reward system. Annual Incentive The executive reward system, an nual incentive plan also forms an important part of the total reward and incentive system for the executives (Lepak, 2013). It helps in benchmarking the total work as per the quantitative and qualitative performance standards (Lepak, 2013). To ensure individual accountability the incentive system is designed in such a way that executives are able to accomplish the goals

Colour and Culture Assignment Example | Topics and Well Written Essays - 500 words

Colour and Culture - Assignment Example he color is considered powerful and forbidding especially when not accompanied by another color, when black is accompanied by other colors such as white, it symbolizes elegance and formality. For as much as the Japanese culture has existed, the white color has been used to represent purity and cleanliness and in their religion it is considered as a blessed color (Addiss, Rimer, & Groemer, 2006). The white color is used in happy events such as weddings and other joyful life events. The color is even used in the Japanese national flag due to their respect for culture. According to the Japanese culture, the red color represents powerful ideas and energy. The color is also used to symbolize love and sexual desires. It is used in their national flag to show that their country is rich in ideas and has power. The blue color symbolizes a state of purity and cleanliness and this belief was drawn from the blue waters surrounding the islands in japan. Blue color also shows calmness and stability (Addiss, Rimer, & Groemer, 2006). The color is majorly worn by females to represent purity and cleanliness especially in unmarried women. Green color symbolizes fertility and progression of the culture. It is mainly associated with the youth to show their vitality and energy to grow. The green color also symbolizes eternity and most of the things to be preserved for many years are painted green (Addiss, Rimer, & Groemer,

Examination of minimalist architecture and it's influence on our way Essay

Examination of minimalist architecture and it's influence on our way of living - Essay Example Despite this, minimalist architecture, regardless of where it is, who designed it, when it was created or what the end use is intended to be, tends to share a number of similarities. A study of two exemplar structures will reveal how some of the common characteristics of this approach are expressed which can then be used to examine how modern lifestyles might have been influenced by the movement. It is concluded that minimalist design has caused today’s society to be more conscious of the space they occupy, leading to a greater push for ‘green’ design and an effort to protect the environment we live in. Architecture works in many ways to help shape and define a culture. Rather than simply erecting a specific building, the work of the architect can contribute to the advancement of a society through its artistic achievement, engineering or technical advancement, political statement or through a variety of other means. Like art, what a building communicates about the customs and culture of the time in which it is built depends somewhat upon how it is viewed and used by the people around it. Similarly, what it is able to achieve in terms of political or other statements is dependent upon the reactions of these same individuals. Within this context, modernity is often described as a collection of studies into the social processes that order the world we live in while remaining in a constant state of flux. If one is speaking with Marshall Berman, modernity is described as â€Å"a mode of vital experience—experience of space and time, of the self and others, of life’s possi bilities and perils—that is shared by men and women all over the world today. I will call this body of experience ‘modernity’.†1 It encompasses the social changes that are constantly taking shape, the way in which these changes are experienced and the reflection of these experiences in various circles. It is a world of definition and ambiguity, a world of

Strategic Management of AtomFilms Case Study Example | Topics and Well Written Essays - 750 words - 1

Strategic Management of AtomFilms - Case Study Example    In the B2B, AtomFilms acquired content through major film festivals using grassroots public relations. It also distributes content through finding distribution channels that would buy the films. In 1998, Air Canada bought five films for its short-haul flights opening up an opportunity for success for AtomFilms. The B2C was not much successful because advertising and merchandise revenue overshadowed it but it built the company’s brand identity, consumer outreach, and marketing strategy. The two strategies helped the company grow as the consumer confidence grew. By the year 2000, the company had generated more than $5 million in revenue. The B2C had helped the company gain $1 million in revenue from merchandise sales through the company’s website. Despite the fact that the elements of the business model are mutually consistent and reinforcing, the company had not found the best way to use its website to monetize consumer traffic (Hill & Jones,  2013). Mika’s possible approaches correspond to forward integration, market penetration, and market development strategies. First, the B2B and B2C approach correspond to the forward integration strategy in the sense that it sought to gain ownership over distributors. AtomFilms developed its content distribution network by calling every distribution channel to sell its products. It also established a website to directly reach consumers and promote sales. The company’s approach also corresponds to the market penetration strategy in the sense that it sought to increase its market share for present products through B2C approach. This was launched after B2B to increase advertising and offer extensive sales promotion items and to increase publicity efforts (David,  2013).   

Business LAW Assignment Example | Topics and Well Written Essays - 2000 words

Business LAW - Assignment Example The main service offered by Acas is dispute resolution. Therefore, the organisation uses three main ways of resolving a disagreement between parties. The first one is conciliation. Conciliation occurs when the organisation tries to find out the issues that bring disputes between the parties. The reason for conciliation is to aid the parties to come to a mutual agreement in solving their differences. Therefore, conciliation seeks to give the parties in a dispute the room to evaluate their differing positions before coming to a conclusion. In conciliation, ACAS l meets both parties in private before bringing them together with an aim to rebuild the bruised relationship. In addition, any decision arrived at is legally binding upon the parties. In addition, ACAS uses arbitration. In arbitration, the parties in a dispute usually agree to involve a third party in case of a dispute arising to decide on the dispute and make any awards where applicable. ACAS is more informal in this, and it a voids formal processes that go on in courts such as formal pleadings and documentaries. Parties coming for arbitration in ACAS must first agree to take part (Gennard and Judge 2005). The agreement must be in writing outlining the issues to be negotiated. In addition, the terms of reference are determined by the disputing parties, and where they are not able, they are helped by an ACAS conciliator. The organisations are committed to good conduct and fairness with its decisions being final, and the awards given difficult to be challenged. Mediation is the third method used by ACAS, and it bears some similarities with arbitration. The major difference is that no awards can be got from mediation. The mediators usually take an active role in dispute resolution proceedings to help the disputing parties find solutions. After that, the mediators make recommendations to the parties, and it’s upon the parties to

Army Profession of Arms Essay Example for Free

Army Profession of Arms Essay The Profession of Arms Campaign is mandated by John M. McHugh, secretary of the Army, and Gen. Martin E. Dempsey, Army chief of staff, to assess the state of the Army and take a critical look at how the past decade of war has impacted the military and civilian workforce. â€Å"The overall objective of the campaign is for Soldiers and leaders to refine their understanding of what it means to be professionals expert members of the Profession of Arms after over nine years of war and to recommit to a culture of service and the responsibilities and behaviors of our profession as articulated in the Army ethic,† Dempsey said. Another Army leader talked about what the campaign means for all those serving in the Army, whether Soldier or civilian, and how it is designed to help transition from the past decade of continuous conflict into a still-uncertain future. â€Å"The Army has decided to introduce the campaign for the Profession of Arms to develop leaders of character and competence required to meet the dynamic challenges of the 21st century,† said Lt. Gen. Robert L. Caslen, U.S. Army Combined Arms Center and Fort Leavenworth, Kan., commanding general. â€Å"This campaign is designed to define and reinvigorate what it means to be a professional in the Profession of Arms. As we embark on this mission, we must reflect on the values and traits that define and distinguish us as a unique profession.† Lt. Gen. Richard P. Formica, U.S. Army Space and Missile Defense Command/Army Forces Strategic Command commanding general, has initiated a command-wide review of what it means to be in the Profession of Arms. This review is part of a broader Army wide effort and leaders across the command are getting involved in this open collaborative process to solicit and capture feedback from its Soldiers and civilians. This campaign will also be a teaching opportunity to help better understand what it means to be in this profession and what it means to be in public service that distinguishes a profession from a career. For the workforce at USASMDC/ARSTRAT, the Profession of Arms Campaign is a chance to give input to the Army on how the past decade has influenced, both good and bad, those serving their nation in wartime. â€Å"For the Army as a whole, this is a chance to assess a lot of what impact the last 10 years of being at war has had on our workforce. It is a chance to take note of what we need to do right now, what we need to do in the future and what direction we need to go in, and I think this could have a great effect on SMDC as a whole,† said Lisa Ratley, Concepts Division, Future Warfare Center-Battle Lab. â€Å"We will conduct some roundtable groups and town hall-type meetings with civilians, officers and noncommissioned officers that will take input from everyone. â€Å"This is a great opportunity for SMDC to gather input and have something to say to the Army as a whole,† she added. In the Profession of Arms Campaign, there are five ‘cohorts’ that the Army is looking at. They are officers, noncommissioned officers, warrant officers, junior enlisted Soldiers and civilians. The campaign focuses on three questions: What does it mean for the Army to be a Profession of Arms? What does it mean to be a professional Soldier? After nine years of war, how are we, as individual professionals and as a profession, meeting these aspirations? â€Å"The Army chief of staff and secretary of the Army are concerned about what effect the last 10 years of war is having on the Army,† said Donald Long, FWC-BL. â€Å"They want to assess the impact of it and to keep ahead of what has actually changed, and how do we implement fixes to any problems or issues that may come up so we can continue to be a professional Army. â€Å"The Profession of Arms Campaign was officially going to end in December but the commanding general of SMDC wants to extend it to include the next 18 to 24 months of professional development for the civilians, Soldiers and officers in the command to provide professional development on what it means to be a professional in this Profession of Arms,† Long added. The Army has also sent out 20,000 surveys to civilians across the Army to get an input from the workforce. â€Å"To me, working for the Army is not just a job, it is an understanding that we are here to serve the American people,† said Ginny Partan, FWC-BL. â€Å"I think the Profession of Arms Campaign is going to help us bridge the gap between 10 years at war and where we need to head in the future. It is going to help us take a hard look at ourselves, across the spectrum from Soldiers to civilians, to see what we are doing right and where we can improve so that we are better in the future.†

Of Mice and Men Essay Example for Free

Of Mice and Men Essay As Curleys wife lay their motionless, her golden curls draping around her petite neck while her crisp, white blouse ruffled gently as the breeze blew through the barn door. The golden sunlight of the setting sun bathed her in an orange glow; her lifeless face was lit up as Lennie sat their on his haunches muttering the same words over and over again, lady, hey lady, lady He still didnt realise that she was, dare I say it, dead. Once again a something so full of life has returned to the Earth from whence it came, and all of this was the fault of Lennie. The big guy was just sitting there, not knowing what to do he just sat there, his cropped hair and stubble looking orange in the sunlight, his big nose, eyes and mouth unknowing and not moving began to change his expression as his slow brain began to conform to what he had done. MURDERED! He began to cry out, George, George, help me George, please help me! Meanwhile George was in the local brothel setting bout a while watching the ladies dance. The sunlight was gradually fading as it dropped behind the clouds just above the horizon, George looked at his wristwatch, all battered and scratched from the many years of ranch working it had endured, and decided that it was time to leave, Slim acknowledged that he was leaving and followed him out of the door. Just as they arrived back the tip of the setting sun dropped below the horizon, the time was approaching half past eight, and the air was chilling slightly, George pulled his jacket tighter around himself as they both walked into the ranch. Lennie was sitting on his bunk, as George walked in Lennie looked up at him. Straightaway George knew that something was the matter, not knowing what was up George asked him whats the matter with you Lennie? N Nothin George, honestly, nothin . This reply indicated to George that something was definitely the matter with Lennie. Cmon Lennie, somethins up, you cant hide it from me I know you too well, Uh uh, I didnt mean to, honestly George Maybe youd better just show me huh Lennie? Lennie walked out of the door closely followed by George. As the two of them walked out Slim walked in after a game of toss the horseshoe, puzzled he followed the two of them to the barn. Lennie stood at the door of the barn and pointed inside without looking in. George and Slim looked at each other and walked inside not knowing what they would find. Wheres he gone? George cried in surprise, he was standing here not two minutes ago. While George and Slim had been inside Lennie had made a break for it! I cannot believe this, said George, hes never thought for himself before. Lennie had run into the forest and hidden in the brush right where Lennie had told him to go if anything had happened, which it had, and he had actually done it! He couldnt believe Lennie had done something off of his own back. They decided they should tell Curley as soon as possible, they knew Curley would want to kill Lennie and so they thought they should tell him so he couldnt blame them for keeping it from him. What! I cant believe it! He was both in a state of disbelief and anger. He couldnt believe his wife was dead, and yet he seemed more intent on hurting somebody else because he was hurting himself. His face was twisted and contorted with rage, his eyes were bloodshot, his lips were tight with resentment, his face was beetroot red, he wanted revenge and he was gonna get it. He got up, nobody stood in his way, they didnt see the point, he was so intent on slaughtering Lennie that he left without saying a word, he picked up his luger and headed out into the woods. He cant be far, he said, Ill get the son of a bitch, Ill get him alright , and with that he left. George and Slim decided to round everybody up to try and find Lennie before that savage beast which had erupted inside of Curley found him and slowly killed and maimed him. Where is he? said George, by this time he was getting a bit worried and thought that maybe Curley had already gotten to him. Dont worry Slim said, Im sure we can reason with Curley and try to sort it, no way! Hes so mad not even God himself could reason with him now! They ran on and eventually, thanks to Georges intuition found Lennie in the brush where he had told him to go only a few weeks earlier. Lennie, my God, hes huntin you down, but, but I didnt mean to George, I swear, Okay Lennie I believe you, but he wont listen, hes so clouded with rage he jus wont listen to anybody. Slim decided to leave George and Lennie to talk over what they should do. George went over the plans in his head while Lennie sat there, thinking of what could have been, the poor lummox thought George, he has no idea, the dumb basta suddenly it came to him, I know Lennie what George, what? George knew he couldnt tell Lennie his plan, it would take too long, especially as Lennie would have been to thick to work it all out, quick Lennie, turn around and look up to those mountains, as Lennie slowly turned around to look up to the mountains George put his plan into action. Lennie he said, in a few seconds youll be on the floor, dont move and dont say a word until I come back tonight to get you, George was unable to tell if Lennie had understood or not, but surely it would be worth a try. He kicked Lennies legs out from underneath him, as Lennie fell to the ground George pulled out a luger from under his coat and pulled the trigger. Lennie hit the ground the shot rang out around the mountains. It was completely still after the animals and birds had fled in terror. George just collapsed onto his haunches, Slim had heard the shot and was first to get to George, whats happened? he asked. Ill tell ya later he replied. As he finished his sentence Curley and the others turned up. Candy took off his hat and held it to his chest, some of the others did the same, there was a few moments silence before Curley cried out you dumb asshole! I was supposed to kill him, he killed my wife, pointing to Lennies body on the floor. George quickly began to defend Lennie saying he didnt mean to, hes just a big dumb nobody, you wouldnt have taken any pleasure from it anyhow! Curley didnt have a reply to this; he thought he had probably acted too rash causing the death of somebody else. Curley may be heartless when it comes to beating people up, but killing someone is a little harsh, even for someone like Curley. As they walked away Curley and Candy were chatting about what they couldve done on the farm, Candy was close to tears, George couldnt stand it any longer, he couldnt keep a secret from someone he had grown trust. He told Candy hes not dead whatre you talking bout replied Candy, hes not dead George insisted, how? You shot him in the head, or so you told me, did you see any blood stains or bullet holes, you underhand, sly son of a I just couldnt think of any other way, he told Candy. This cannot get out among the other ranchers, said Candy, I know, I know came Georges reply. George and Candy went into one of the other barns alone so they could talk over what to do about the undead. They decided to leave that night, Candy would clear out his bank account which he had been saving for so long and George decided to do a big heist on the ranch that night. He knew they wouldnt be able to buy a farm or ranch of their own with Candys money alone. They couldnt stay and work there any longer because Lennie would die if he were left in the forest alone. They decided to do it that night and enrol the help of a few of the old hands. George went and spoke to Slim about the possibilities of this so-called job Slim went along with it, but would Carlson. Candy went and spoke to him, he was in. Slims guilty conscience suddenly kicked in, what about the others? What about the others? Candy said. Well, if we take all the money from here then theyll lose their jobs and have no money, hes right ya know George said. Well thats it then, said Carlson, maybe not, why dont we ask them all to help out? Thats a great idea George, but what if one of them refuses and grasses us up to Curley or even the boss! I think thats a risk we should take. I agree, we might as well, we wont have enough money if we dont. What if Curley What if Curley what? What if he got jumpy and whacked one of us? Again, a risk we gotta take, now enough of the what ifs lets do this thing, said George. Yeah! Lets do it, they all said in unison. That evening there was a bustling of activity and organisation. By nine thirty they were all in, all that is except the nigger. They had to try and persuade him as well, because after all everyone deserves a chance, no matter of race, colour or creed. They entered his lone bunkhouse; he was agitated by this mass gathering and was a little jumpy, there was a bead of perspiration running over his furrowed brow, he didnt know what they wanted, he thought they may harm him in some way, but he relaxed when they told him their plan. He was in. He was so happy that someone had wanted to include him, after all, hed been dismissed as a nigger thousands of times, no-one had ever asked him to help with anything big before. They were all in! One by one they came up with suggestions and plans and ways and means of achieving their goal. By the time the plans were finalised it was one thirty. The moon was just above the horizon; it looked larger than normal, the craters and the seas were extremely bright. The whole ranch was lit up, all the stars were visible, and there was not a cloud to be seen in the night sky. What a night, said George, I just hope that Lennie hasnt run off, maybe one of us should go check on him, said Crooks, nah! Replied George, hell be just fine. And with that they began their operation. The nigger was on lookout as was Whit, one at the entrance and one by Curleys bunkhouse hidden in the bushes. George was the brains of the operation and had been secretly observing, over the few weeks he had been there, where Curley was taking the money at the end of the day. He had first had the idea of raiding the ranch when hed come back late from walking one night and saw Curley through the window putting money into the safe, he never thought that his idea would actually come of age, but quite a lot had changed since that day! Slim was Georges rear guard, because he was the most trusted member of the ranchers, who went in while George cracked the big, black safe to which nobody but Curley knew the contents of, and watched his back. There would be no guns except for one because it would be too much of a risk. Carlson was to be the only man with a gun as he was the most experienced member of the group and could handle guns sensibly and was not trigger-happy. While all this was happening the remaining members of the ranch would be ready, in case there was a problem with Curley, or anyone else for that matter, and were ready to pounce and sort out the problem, no questions asked! So the plan was sorted. No one was without a job; everyone was in place, ready and waiting. George and Slim crept out of the bunkhouse wearing their darkest clothes. George had black trousers; a black shirt with a black waist jacket and a dark brown peaked hat, slim was wearing all black with mud on his face. They could hardly be seen in the shade of the moonlight, but when they came out they were a little more suspicious. Bushes and other buildings were their only cover, and they had to creep right outside Curleys window, would he be asleep or would he still be awake planning what to do with his wifes body, it still lay where it had last come to rest at the fate of Lennie. Luckily for them Curley had drifted off to sleep in his armchair with a whiskey bottle in his hand, probably trying to drown his sorrows, poor bastard! He thought, he wont rouse til mornin for sure, but as he said that he stepped on a twig. There was a metaphorically speaking deafening cracking sound. George and Slim stopped instantly, petrified, they were stuck to the spot, not one of them dared move for fear of Curley. Neither wanted to turn around in case Curley was sanding there with a luger in his hand pointing it straight at one of their heads uttering the words what the hell dya think youre doing? It felt like an eternity passed before George turned his head and looked around his shoulder at Slim, whereas it was only a matter of a minute or two. He cant have waken, said Slim looking over the window sill to confirm this, nope, sound as a baby! Thank the lord above for that, said George. They continued their journey and eventually arrived at the office. George put his hand up to the knob and turned, he pushed the door but it wouldnt budge. What! exclaimed Slim when George told him the bad news, however the good news is that I spy a window on the other side that looks to be open, I cant be sure but its definitely worth a try, he said to Slim, lets go Slim replied. They made their way around to the other side of the office finding that the window was open he pushed it upwards causing a lot of noise in the process. Damn it George! I couldnt help it, he replied irritably. They waited to see if Curley had heard, meanwhile Whit was staring intently at Curley, he saw him stir and then drift into a deep drunken sleep again. He breathed a sigh of relief as he looked over to the office and saw George and Lennie staring transfixedly at him waiting for a signal that everything was okay, he gave them the thumbs up and they proceeded to climb in through the now open window. Inside George began the tedious operation of cracking the safe. He had managed to embezzle a stethoscope out of the doctors emergency room so he could listen to every turn of the code-wheel inside the safes portly door. Slim looked down to his watch as he looked out of each window of the office in turn he saw it was getting quite early, the time was now twenty past four, the sun would be rising soon and that meant that their cover would be blown and the game would be up. He also noticed that his ageing hairy hands were perspiring rather more than they should be. For the first time in his adult life he was nervous and was becoming very irrational. George tried to calm him down as he worked on the safe; luckily Slim sat down and calmed himself. George had made two successful turns of the knob and was onto the final and most crucial turn, he concentrated so hard that even an earthquake or tornado could not have disturbed him. The final click came to Georges ear, he pulled the lever to open the door only to find there was yet another door, this time requiring a key. George felt like screaming out but contained himself. He told Slim to stay where he was, George had come this far and he wasnt about to give up easily. He clambered out of the window making no noise at all. The sky had clouded over slightly and the moon was now gone, he noticed over the horizon the black of the night sky turning dark blue, he realised that dawn was approaching and knew he didnt have a lot of time to find that key, the key to all of their freedoms and work-free days, and also to Lennies rabbit farming plans. I cant let them down, George said to himself, especially not Lennie! He arrived at the door to Curleys bunkhouse, he slowly turned the doorknob and yes thought George to his amazement, the door clicked open and with a light push George opened the door. Curley was sitting in the same armchair as he was before. His position had changed slightly but nothing was going to put George off of finding that key, that key that was hanging round Curleys neck, it glinted in his eye almost wryly smiling at him as if it had one their metaphorical game of hide and seek. It was the biggest setback to the heist so far. George rubbed his sweat-covered hand over his stubbly chin. There was only one way to open that safe, there was only one way to get the key that would that, he would have to go right up to Curley and lift it off of his neck. He inched his way up to Curleys chair bit by bit, not making a sound, not breathing, when all of a sudden Curleys head rose, he drew breath and then lolled his head forward. Georges prayers had been answered, the key now hung loosely around Curleys neck instead of being pulled taut about his chest. George moved swiftly, he pulled the chain off and was out of there in a flash. Whit looked at him in amazement from his hideout in the bush and just gave him the thumbs up as he wiped his own sweat-covered brow. Back inside the office Slim noticed that the time had moved on quite considerably since he had last looked, it was now a quarter past six and the sun was beginning to poke its proverbial yellow head over the horizon. Slim rubbed his bleary eyes and told George who by now was loading his bag with cash. Holy cow George! Thats enough to feed a village for a month, youre telling me replied George, he must have been keeping it all for himself, greedy git! Well show him, lets take the lot and keep the key, hell never know how much we got and by the time he sobers up well be long gone. Youre right, well give him a taste of his own money, he kept our hard earned cash away from us so well keep his not so hard earned cash away from him, permanently! Yeah! Lets get out of here, said George. They both got out the window and crept their way over to the exit, Whit followed slightly behind them, he caught up to them and said, well you guys have used up at least three of your nine lives tonight, tell me about it, said Slim, I got so nervous at one stage I almost bottled-it! Anyway, how much was there in that safe, we dont know George told him, we didnt really hang around to count it! Course not, I understand, replied Whit. Lennie had stayed in exactly the same position for the whole night, when they saw him lying there they thought that something was wrong with him, but amazingly he had carried out Georges every word to the letter, he hadnt moved, not even an inch, since George told him not to, he had no idea about the raid on the safe he hadnt a clue that they all planned to help make Georges idea of buying their own ranch a reality. He couldnt believe it when they told him, he was to have a new life, new friends, new rabbits, he was overjoyed and he was speechless, probably a good thing, because nothing intelligent ever came out. All in all it had been a satisfying end to a hard nights work. They were all shocked to find out how much Curley had had stashed away in there. That mustve taken him a good few years and a good few tax evasions to rack up that much, exclaimed Carlson when he saw how much there was. There were many comments like this as the group walked down the road to their freedom, the sun had just risen straight ahead of them, George and Slim lapped up the praise as they walked into their new lives and their new-found wealth. I just feel sorry for Curley, said Candy. Nah! they all said in unison.