Unit 11 Flow Of Energy And Elements Through The Environment

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Unit 11

Flow of Energy and Elements through the Environment

That producers are green plants, able to manufacture glucose using sunlight, water and carbon dioxide.

That a simple food chain describes the relationship between producers, consumers and top predators.

That a food web describes the feeding relationship of many organisms within a habitat.

The energy flow through a food chain or web.

That energy is lost between each trophic level.

How energy is lost through each trophic level.

That toxic chemicals like DDT can be bio- accumulated through a food chain.

That elements like carbon and nitrogen are recycled in the biosphere.

Some of the effects of disrupting the carbon cycle.

The main likely consequences of global warming.

Producers, Consumers, Plants, Predators, Photosynthesis, Food chain, Food web, Biomass, Energy, Flow, Feeding, Relationship, Kilojoules, Tropic, Level, Elements, Carbon, Greenhouse, Effect, Fossil fuels, Nitrogen, Recycled, Biosphere, Global & Warming. Unit 11: Flow of Energy and Elements through the Environment web: www.science-interactive.co.uk email: sales@science-interactive.co.uk Science Interactive LTD PO BOX 50764 LONDON NW6 9AT Click mouse to begin Science Interactive LTD Copyright 2005 Understand: Keywords:

Plants are called producers because they produce all the World’s biomass via a process called photosynthesis. Plants use energy from the s______ to combine carbon dioxide and w________ to form g__________ and oxygen. This reaction produces millions of tonnes of living matter, that nourishes all other living organisms in the animal kingdom. The oxygen that plants release into the atmosphere is used during cellular r_____________ by all living organisms. How can we determine the biomass of a plant ? Plants as producers: Producers plants one Science Interactive LTD Copyright 2005 Word bank: sun water glucose respiration C 6 H 12 O 6 6O 2 6CO 2 6H 2 O Plant cells Chloroplast Energy Glucose Plant yield: (kg per hectare) 14000 10000 6000 2000 <1000 Plants only use a small fraction of the sunlight energy, they receive every year. Despite this, sugarcane produces up to 200 tonnes of glucose per year per hectare. The most productive areas are the equatorial regions that receive the most sunlight energy. Plant yield Green chlorophyll contained in palisade chloroplasts are able to use light energy to enable carbon dioxide and water to combine to form glucose and oxygen. Notes Diagram Photosynthesis in action

Plants produce all the nutrients (proteins, carbohydrates and lipids) that supply the World’s f_____ chains. This includes the dietary nutrients that directly (through plant produce) or indirectly (through consumers) supply the human population. Plants use light energy to combine w_______ and carbon dioxide to form glucose and oxygen. Glucose is a store of chemical energy and is used for cellular respiration by the plant or used to manufacture its lipids, carbohydrates and proteins. Energy changes during photosynthesis: Products Substrates C 6 H 12 O 6 6O 2 6H 2 O 6CO 2 Activation energy Net energy taken in during reaction Science Interactive LTD Copyright 2005 Progress of reaction Potential energy Producers plants two Word bank: food water O 2 H 2 O CO 2 C 6 H 12 O 6 In this reaction H 2 O and CO 2 substrates are combined in the plant leaf cells using light energy to produce glucose (C 6 H 12 O 6 ) and O 2 . Key Photosynthesis in green plants

The glucose produced during photosynthesis in green plants is used to make plant c____________, lipids and proteins. Every year over 70,000,000 kJ of sunlight energy falls on every metre squared of land. Plants only use about 90,000 kJ/m 2 / year of light energy during photosynthesis, however they produce over 130 billion tonnes per annum of biomass, globally. Overall plants y______ depends on a number of factors including light availability, soil quality, rainfall levels and competition. How could you determine the yields of different crops over time ? Plant yield and biomass: Producers plants three Science Interactive LTD Copyright 2005 Word bank: carbohydrates yield Rice, rich in carbo-hydrates can produce a yield of up to 3000 kg per acre Rice Wheat, rich in carbo-hydrates and sugars can produce a yield of up to 2500 kg per acre. Corn, rich in proteins and carbohydrates can produce a yield of up to 5500 kg per acre. Sugarcane, rich in glucose can produce a yield of up to 9000 kg per acre. Notes Diagram Crop Sugarcane Corn Wheat

Plants are extremely efficient at transforming the e________ carried by light to chemical energy trapped in glucose molecules, which are produced during photosynthesis. Their efficiency is about 80%, far higher than typical values for h__________ and carnivores. Only a small fraction of the chemical energy they produce in the form of glucose is lost through respiration or waste. How could you determine the amount of glucose that is used during cellular respiration in plants ? Plants using light energy : 1 1 2 2 3 3 Biomass Waste Respiration Biomass: Energy contained in the tissues of the plant (available for the next level) Waste: Energy contained in the waste materials found in leaves. Respiration: Energy used in cellular respiration by all plant cells. 8,000 kJ 1,500 kJ 500 kJ Light energy 10,000 kJ Producers plants four Science Interactive LTD Copyright 2005 Word bank: energy herbivores Only a very small fraction of energy is used for respiration or lost as waste. Plants are almost 80% efficient as producers. The transfer of energy from the sun’s rays to the glucose found in plant leaves is achieved during photosynthesis. Plants are highly adapted and efficient at transforming light energy to chemical energy. Over 132 billions tonnes of plant biomass is produced globally every year. Notes Diagram Plants use of light energy Process

Primary consumers herbivores Primary consumers or h___________ ingest, digest and assimilate plant nutrients produced as a result of photosynthesis. Herbivores are the most efficient animals, able to survive only by feeding on nutrients from plants. Herbivores provide a rich protein source for secondary and tertiary consumers. They are highly adapted to d_______ and breakdown the cellulose found in the cell wall of plant cells. Most carnivores including humans are unable to digest this plant polymer. Plant cellulose is known as what in the human diet...it is one of the seven essential food groups ? Primary consumers: Science Interactive LTD Copyright 2005 Word bank: herbivores digest Rabbits feed on grass and other small shrubs. Their success is because of their high reproductive rate. Rabbits Buffalo graze almost exclusively on grass, turning this simple nutrient source into valuable animal flesh rich in proteins. Caterpillars search for and consume plant leaves rich in sugary sap to absorb and assimilate in their own bodies. Tree cutter ants can carry and consume many times their own body weight of plant material such as leaves. Notes Diagram Herbivore Tree cutter ants Caterpillars Buffalo

Secondary consumers carnivores Secondary consumers or c____________ ingest, digest and assimilate the nutrients found in herbivore bodies. They, like tertiary carnivores or top p____________ rely on the rich content of p_________ found in the flesh or muscle tissue of herbivores. Like all animals and plants, they are highly adapted to catch and kill their prey. The spider for example produces a highly complex web to catch insects. Spider silk is stronger than steel weight for weight. It also injects its prey with a toxin that causes paralysis. Secondary consumers: Science Interactive LTD Copyright 2005 Word bank: carnivores predators protein The Brazilian tree frog feeds on small insects or mammals, by catching them on their ‘sticky tongue.’ Frogs Spiders spin webs to catch small insects and like snakes paralyse their prey with venom. Snakes feeds on small animals and paralyse their prey before its digestion with venom. Ladybirds feed on aphids which are found on many plants. They are natures own pesticides. Notes Diagram Carnivore Ladybird Snakes Spiders

Primary and secondary consumers Primary consumers ingest, d______ and assimilate the nutrients found in plants. Secondary consumers rely on the nutrients provided by eating the bodies of herbivores. Both primary and secondary consumers are inefficient at turning what they consume into tissue biomass which is then available for the next trophic level. This is because a large part of the nutrients they consume is used in c___________ respiration to provide the energy for movement, cellular respiration, keeping warm, growth and repair. Their average efficiency is only about 20% compared to plants which are about 80% efficient. Primary and secondary consumers : 1 1 2 2 3 3 Biomass Waste Respiration Biomass: Energy contained in the tissues of the consumer (available for the next level) Waste: Energy contained in the waste materials excreted by consumers. Respiration: Energy used in cellular respiration by all tissues and cells. 2000 kJ 6000 kJ 2000 kJ Nutrients 10,000 kJ Science Interactive LTD Copyright 2005 Word bank: digest cellular Only a very small fraction of energy is turned into biomass for the next feeding level. Consumers are about 20% efficient. The transfer of energy from plant tissue through the bodies of herbivores to the next feeding level i.e; secondary consumers is relatively inefficient. This is because a large part of the nutrients they consume is used in cellular respiration to provide the energy for movement, keeping warm and repair. Notes Diagram Energy efficiency of consumers Process

Unusual carnivores Even in the plant kingdom, we can find some examples of plants that cannot produce sufficient nutrient by p_____________ alone. They rely on trapping and digesting the nutrients of small insects and sometimes animals. The Venus fly trap lives in very poor soil and supplements its nutrient requirements by trapping and digesting small insects. The fly is attracted to the brightly coloured petal which resembles animal flesh. The leaves close and enzymes begin to d_______ the insects’ body. Carnivorous plants: Science Interactive LTD Copyright 2005 Word bank: photosynthesis digest The sundew has hundred of tiny hair-like protrusions which catch very small insects. Like many other carnivorous plants, they habit nutrient poor areas. Sundew plant The Heliamphora attracts small insects like flies by producing a smell like rotting meat. In the flower, a sticky fluid which contains enzymes digests its prey. The venus fly trap, the best known carnivorous plant closes shut on its prey. It is then able to digest, and absorb the nutrients using enzymes. Notes Diagram Plant Venus fly trap Heliamphora

Top predators carnivores one Top predators like lions, wolves, killer whales and brown bears are located at the top of the food chain or web and have no natural p____________. They are usually highly evolved to catch and kill their prey, equipped with speed, strength, forward facing v__________, good hearing and canine t_________. Successful top predators have a very varied diet relying on many different animals for their proteins, lipids and carbohydrates. Name three other top predators and their adaptations ? Top predators: Science Interactive LTD Copyright 2005 Word bank: predator vision teeth The killer whale is able to catch and kill prey like dolphins and seals in a marine environment. Killer whale The brown bear hear in this picture is taking advantage of salmon returning to spawn. Artic wolves and wild dogs hunt in large packs to increase their success when they hunt their prey. Tigers and other big cats are highly adapted to stalk, chase and kill their protein rich prey. Notes Diagram Predator Tiger Wolf Brown bear

Top predators carnivores two Tertiary consumers or top predators ingest, digest and assimilate the nutrients found in the bodies of herbivores or secondary consumers. Top predators are the least efficient at turning what they consume into tissue biomass which is then available to the next trophic l_______ ...decomposers. In this case, to decomposers which will then recycle some of the nutrients trapped in the dead bodies of top predators back into the soil. This is because a large part of the nutrients they consume are used in cellular respiration to provide the e_________ for movement, keeping warm and repair. Their average efficiency is only about 15% . Top predators : 1 1 2 2 3 3 Biomass Waste Respiration Biomass: Energy contained in the tissues of the consumer (available for decomposers) Waste: Energy contained in the waste materials excreted by consumers. Respiration: Energy used in cellular respiration by all tissues and cells. 1500 kJ 6500 kJ 2000 kJ Nutrients 10,000 kJ Science Interactive LTD Copyright 2005 Word bank: level energy Only a very small fraction of energy is turned into biomass for the next feeding level. Top predators are about 15% efficient. The transfer of energy from the bodies of top predators to the next trophic level (decomposers) top predators is very inefficient. This is because a large part of the nutrients they consume is used in cellular respiration to provide the energy for movement, keeping warm and repair. Notes Diagram Energy efficiency of predators Process

Decomposers Decomposers including b__________ and fungi play a vital role in the recycling of nutrients trapped in the bodies of primary and secondary consumers. Bacteria help break down proteins carbohydrates and l_________ in all organisms producing simple soluble molecules that can be reused by plants. These molecules are taken from the soil by the plant root system using active transport. Without this recycling of nutrients, plant growth would be severely affected. Why is the soil in graveyards always rich in nutrients ? Decomposers: Science Interactive LTD Copyright 2005 Word bank: bacteria lipids Moulds also play a large role in recycling small molecules and nutrients making them available to plants. Moulds Sewage including animal waste is rich in nutrients including nitrogen. It is usually spread over the land like many fertilisers. Fungi grow and breakdown mainly dead plant materials releasing nutrients back into the food chain. Bacteria cells exist everywhere and it is estimated that their total cell biomass exceeds that of all other species. Notes Diagram Decomposers Bacteria Fungi Sewage and waste

Food chains one Food chains shows us what eats what in a particular habitat. They show the flow of nutrients or food energy from producers through p_________, secondary and tertiary consumers. Food chains always begin with a producer, usually a green plant and end with a top predator. In the following food chains, what would happen to the number of secondary consumers and producers if the primary consumers died (slugs and caterpillars) Food chains: Science Interactive LTD Copyright 2005 Word bank: primary Hedgehog Robin Fox Caterpillar Oak leaves Two Diagram One Oak leaves Slug Sparrow hawk

Food chains two There are many food chains and webs found in marine environments. Within marine environments about 90 billion tonnes of biomass are produced each year. This is not surprising, since the oceans and seas receive over 70% of the s_______ energy from the sun. Humans only take 0.02 billions tonnes per annum out of marine ecosystem, which remain an untapped resource. Find out how low levels of crude oil in the sea can dramatically affect marine food chains ? Marine food chain: Science Interactive LTD Copyright 2005 Word bank: sun’s Crabeater seals feed predominately on krill and other fish. They assimilate the krill proteins into their bodies. Crabeater seal The killer whale, is a supremely adapted marine organism which feeds mainly on crabeater seals and dolphins. Krill filter and trap small plankton. They provide a rich protein source for secondary consumers like seals and the blue whale. Plankton use light energy, CO 2 and water producing part of the 90 billion tonnes of marine biomass per year. Notes Diagram Plankton Krill Killer whale

Food webs one In most habitats, primary, secondary consumers and top predators feed on more than one species of plant or animal. Furthermore, if two species relies on only one food source this will increase c_____________ among species. A food web is made up of many food chains and gives a more complete picture of how herbivores and carnivores feed. Look at the woodland food web, find all six separate food chains ? Woodland food web: Oak leaves Grass Mouse Earthworm Snail Fox Weasel Rabbit Owl Hedgehog Science Interactive LTD Copyright 2005 Word bank: competition Carnivores Producers Herbivores Top predators

Food webs Two Marine habitats are home to many different feeding relationships, which can also be shown by a food web. In the great o________, nutrients from the seabed are constantly being brought to the surface by ocean currents. Colder oceans are more productive because of their stronger currents. Look at the marine food web, find all five separate food chains ? Marine food web: Algae Seaweed Barnacle Limpet Crab Dog whelk Mussel Seabird Starfish Periwinkle Science Interactive LTD Copyright 2005 Word bank: oceans Carnivores Producers Herbivores Top predators

Biomass Biomass Biomass Biomass Waste Waste Waste Waste Respiration Respiration Respiration Respiration Biomass through food chains Using biomass instead of numbers of organisms gives the actual mass of living things at each trophic level. It demonstrates how available b_________ for the next levels is lost through supplying energy for activities like respiration, body heat, movement and reproduction. Some is also lost as indigestible nutrients and w______. Interestingly, of the 130 billion tonnes of World’s plant biomass, only 0.2 billions tonnes enters the human food chain as animal protein like beef, chicken and lamb. Biomass through food chains: 1000 kg 200 kg 30 kg 4.5 kg Eagle Snake Grasshopper Grass Science Interactive LTD Copyright 2005 Word bank: biomass waste Top predator Carnivores Herbivores Producers

Energy loss through trophic levels Losses of energy occur at all trophic levels. Most herbivores only achieve about 20% efficiency. That means for every 1000 kJ of nutrients consumed, only 200 kJ of energy is available to the next trophic level. Most of the energy is used for c__________ respiration, body warmth, movement or remains in undigested food as faeces. Most carnivores can only achieve about 15% efficiency. Why do vegetarians have less impact on the environment ? Energy loss through trophic levels: Nutrients 50,000 kJ 1 1 2 2 3 3 Faeces Biomass Respiration Faeces: Energy contained in the faeces and undigested food of the animal. Biomass: Energy contained in the tissues of the animal (available for the next level) Respiration: Energy used in cellular respiration and for body heat. 20,000 kJ 20,000 kJ 10,000 kJ Science Interactive LTD Copyright 2005 Word bank: cellular Just under half the energy (20,000 kJ) passes undigested through the horse's body, with 20,000 kJ used during cellular respiration. The transfer of nutrients from producers to primary and secondary consumers involves ‘wastage.’ The daily nutrient requirement in kilojoules for a horse is around 50,000 kJ with only 10,000 kJ of nutrients ending up as part of the horse’s body. Notes Diagram Energy use and loss in animals Process

Pyramids of numbers Pyramids of numbers allows us to show the number of individuals within a species at each t________ level . In most pyramids of numbers, the number of organisms decreases as you ascend the trophic levels because of two things: Usually the mass of the organism increases and energy is lost between each level. Pyramid one: The pyramid of numbers shows that 10,000 grass feeds 800 snails which then feed 33 weasels which then 5 foxes. Pyramid two: The pyramid of numbers shows that 1 oak tree feeds 800 snails which then feed 24 hedgehogs which then 7 owls. Pyramids of numbers: 10,000 Grass 800 Snails 33 5 Weasels Fox 1 800 Snails 24 Hedgehog 7 Owl Oak tree One Two Science Interactive LTD Copyright 2005 Word bank: trophic Pyramids of energy one & two Oak tree Snail Hedgehog Food chain Owl Species Grass Snail Weasel Fox Species Food chain

Pyramids of energy one The most accurate method of showing how nutrients are transferred from producers to top predators and the feeding relationships between o___________ is to use an energy pyramid . These energy pyramids show the amount of energy transferred from one level to the next. The energy available to the next level is through growth. Energy is always l_____, as you ascend from one level to the next. Unlike pyramids of numbers, pyramids of energy can never be inverted. Pyramids of energy: 90,000 kJ/m 2 /yr Grass 12,500 kJ/m 2 /yr Snails 2,300 kJ/m 2 /yr Weasels 104 kJ/m 2 /yr Fox Science Interactive LTD Copyright 2005 Word bank: organisms lost Grass Snail Weasel Fox Species Food chain Pyramids of energy The pyramid of energy shows that 90,000 kJ/m 2 /yr is pass to the snail from the grass. The snails pass 12,500 kJ/m 2 /yr to the weasels which then passes 2,300kJ/m 2 /yr to the top predator, the fox. How is this energy lost through the food chain ? Notes

Pyramids of energy two Understanding how energy is lost at each trophic level is important. Some of the energy from ingested food is lost through c_________ respiration and body heat. Some food molecules are not digested, passing through as waste. The further you move up the food chain or w____, less of the original energy found in producers is passed along. Look at the following food chain and pyramid of energy and work out the energy lost at each trophic level. Explain how the energy is lost ? Pyramids of energy: 1,230 kJ/m 2 /yr 8,900 kJ/m 2 /yr 67,500 kJ/m 2 /yr 345,000 kJ/m 2 /yr Crab ________kJ ? _________kJ ? _______kJ ? Science Interactive LTD Copyright 2005 Word bank: cellular web Mussels Algae Starfish The pyramid of energy shows that 345,000kJ/m 2 /yr is passed to the mussels from sea algae. The sea mussels then pass 67,500kJ/m 2 /yr to the starfish which then pass 8,900kJ/m 2 /yr to the top predator, the crab. Work out how much energy is lost at each level. How is this energy lost ? Notes: Algae Mussels Starfish Crab Species Food chain Pyramids of energy

Pesticides and toxic chemicals in food chains Pesticides, heavy metals like m__________ and other chemicals that are not broken down, can enter a producers or consumer’s body and then pass along the food chain. DDT is a chemical sprayed on crops to control insects and in some parts the malaria spreading m___________. In the USA , DDT found in ponds and lakes, was taken up by plant plankton and then accumulated in consumers further up the food chain. The levels of DDT increased from primary consumer (fish) to top predator (grebe), reaching lethal levels. This is called bioaccumulation . Bioaccumulation of toxins in food chains: Fish Grebe Fish Plankton Water 2000 ppm 300 ppm 8 ppm 0.3 ppm Science Interactive LTD Copyright 2005 Word bank: mercury mosquito Water Plankton Fish Grebe Species Food chain Bioaccumulation DDT ppm During bioaccumulation of pesticides and other chemicals, small levels present in the water or producers accumulate in the bodies of primary and secondary consumers. This is because DDT is not easily broken down. The grebe also eats many fish, for each one it eats it receives a dose of DDT . Notes

Predator prey cycles one Predators like ladybirds trap, kill and feed on their prey. The greater the number of predators, the larger the effect they have on prey numbers. The number of available prey also has an effect on the number of p__________. If for example, prey numbers reduce because of disease or lack of plant growth , the number of predators will be reduced. The effect on predator numbers is usually delayed. Remember: numbers are increased in predators by reproduction and reduced by starvation and death. Ladybirds and aphids: Science Interactive LTD Copyright 2005 Word bank: predators Rose bush Aphids Ladybird Species Food chain Ladybirds and aphids Numbers of prey and predators are closely linked. A reduction in the food supply will cause a decrease in the number of predators. However, this reduction is slightly delayed. Explain what causes this delay and why does the weather affect the predator – prey cycle ? Notes

Predator prey cycles two Another predator prey relationship is the snowshoe hare and the lynx. The lynx has to trap, kill and feed on their prey. The greater the n________ of predators, the larger the effect they have on prey numbers. The number of available prey also has an effect on the number of predators, although this effect on predator numbers is usually delayed. In this relationship decades with very hard winters and low plant growth caused a subsequent d__________ in snowshoe hares and then some months later, the total numbers of lynx also decreases. Explain why over the last 100 years there is also a general slow decline in both the number of lynx and hares ? Lynx and the snowshoe hare: Science Interactive LTD Copyright 2005 Word bank: number decrease Snowshoe Hare Lynx Predator prey cycle 0 2 4 6 8 10 normal 37 o C time days 1850 1875 1900 1925 Thousands of hares Snowshoe hare Lynx o Year Thousands of lynx 0 40 80 120 0 5 10 Lynx and snowshoe hares Numbers of prey and predators are closely linked. A reduction in the food supply will cause a decrease in the number of predators. However, this reduction is slightly delayed. Explain what causes this delay and why does the weather affect the predator – prey cycle ? Notes

+ Element cycles Decomposers including b__________ and fungi play a vital role in the recycling of nutrients trapped in the bodies of primary and secondary consumers. Microbes help break down proteins, carbohydrates and l_________ in all organisms producing simple soluble molecules that can be reused by plants. These molecules are rich in two very important elements: Carbon and nitrogen . Recycling nutrients: C 12 6 Bacteria Fungi Carbon Nitrogen Science Interactive LTD Copyright 2005 Word bank: bacteria lipids N 14 7 All life in the biosphere relies on the recycling of nutrient molecules by decomposers including bacteria and fungi. Without recycling ‘life on Earth’ would fail. Recycling Nitrogen is essential for protein manufacture by plant and animal cells. It is found in all amino acids. Plants and animals are all built using carbon chains found in cellular proteins, carbohydrates, sugars and lipids. Notes Diagram Carbon Nitrogen

All living organisms require the element n_________ to make proteins. Although air contains almost 80% nitrogen gas , plants and animals cannot use it in this form. Nitrogen (N 2 ) has to be changed to nitrates (NO 3 - ) before plants can absorb and use nitrogen to build proteins. Animals acquire their nitrogen from plants or animals that feed on plants. The nitrogen cycle shows how nitrogen gas is changed into nitrates. The nitrogen cycle: The nitrogen cycle Nitrates (NO 3 - ) in the soil. Nitrogen fixing bacteria in root nodules Nitrates from fertilisers & lightning Plant and animal remains (NH 3 ) Denitrifying bacteria in soil (NH 3 ) N 2 Atmosphere Soil Atmosphere Plant biomass Animal biomass The atmosphere is 78% Nitrogen gas. Lightning Animal waste Legumes Fertilisers Science Interactive LTD Copyright 2005 Word bank: nitrogen

Factors affecting the nitrogen cycle Intensive farming year after year, reduces the quality of the soil, stripping all the essential plant minerals like n__________. Farmers add fertilisers at the beginning of every growing season to replace these lost minerals. Crop yield increases as the amount of fertilisers is added to the soil. Nitrates that are washed out and end up in lakes and rivers can pollute our drinking water and cause algae to grow using all the available o_________ in the water. Low oxygen levels can kill fish and freshwater invertebrates. How will this affect freshwater food chains ? Factors affecting the nitrogen cycle: Science Interactive LTD Copyright 2005 Word bank: nitrogen oxygen Organic farmers only use natural sources of fertilisers like animal waste or manure. They do not use artificial fertilisers made by companies like ICI. Animal waste Nitrogen fixing bacteria are found in root nodules of plants like peas. The bacteria convert N 2 from the air directly into nitrates (NO 3 - ), a form of nitrogen, plants can use. During a lightning strike nitrogen in the air is converted to nitrates which can then dissolve into the soil. This is nature’s own way of fertilising the soil. The use of nitrate fertilisers benefits modern farming by improving crop yields. Too much can lead to the destruction of many freshwater habitats. Notes Diagram Fertilisers Lightning Nitrogen fixing bacteria

Soil There is 3300 billion tonnes of carbon trapped in oil, coal and natural gas deposits found under rock sediments. The carbon cycle All living organisms require the element c_________ to make carbohydrates, proteins and other important molecules which make up living organisms. Cellular respiration and decomposition by bacteria release carbon dioxide into the atmosphere. Plants use this during p_____________ at the same rate. The amount of CO 2 in the atmosphere should stay the same but it is increasing rapidly because of the use of fossil fuels and deforestation . The carbon cycle: Ocean There is 1020 billion tonnes of carbon trapped in living organisms like algae. CO 2 is also dissolved in the oceans. Respiration CO 2 Atmosphere There is 750 billion tonnes of CO 2 trapped in the atmosphere. This is rising by 3 billion tonnes a year because of fossil fuel use and deforestation. Atmosphere Plant biomass Photosynthesis Land deforestation Buried fossil fuels Fossil fuel combustion Marine biomass Science Interactive LTD Copyright 2005 Word bank: carbon photosynthesis

Causing the greenhouse effect Our atmosphere is changing and will continue to change for many years to come. The average concentration of carbon dioxide in the air is increasing because of human activities. Fossil fuels rich in c________ are extracted deep underground and combusted with o__________ forming over 3 billions tonnes of carbon dioxide per year. We are also destroying large areas of ancient forests in Africa and South America. Why does this affect carbon dioxide concentrations in the atmosphere ? Factors affecting atmospheric carbon concentrations: Science Interactive LTD Copyright 2005 Word bank: carbon oxygen Over 500 million cars are responsible for the release of carbon dioxide found in the atmosphere. Is public transport the answer ? Combustion engine Using renewable forms of energy liked wind power could reduce carbon levels and slow the greenhouse effect. The destruction of the rain forests adds to the carbon dioxide in the atmosphere and also increases the erosion of soil. Combusting fossil fuels like petrol, gas and diesel release over 3 billion tonnes of carbon dioxide every year. Notes Diagram Fossil fuels Deforestation Renewable energy

The greenhouse effect Our planet Earth, is surrounded by an atmosphere, which is a collection of gases including nitrogen, oxygen, water vapour and carbon dioxide . Insulating molecules like carbon dioxide are called greenhouse gases allowing s______ energy to pass through whilst absorbing some of the h______ energy radiating back into space. Correct levels of atmospheric carbon dioxide keeps temperatures ambient. The combustion of fossil fuels and subsequent increases in atmospheric carbon dioxide has caused too much heat energy to be absorbed. The atmosphere is becoming warmer. How can we reduce carbon dioxide concentrations in the atmosphere ? The greenhouse effect: Science Interactive LTD Copyright 2005 Word bank: solar heat Altitude (km) 15 50 Solar radiation Radiated out to space Absorbed in atmosphere by greenhouse gases Altitude (km) Solar radiation Radiated out to space Absorbed in atmosphere by greenhouse gases 15 50 More deserts The polar ice caps are melting, reflecting less heat energy back to space and causing rising sea levels. Arid land found in Africa and the Middle East will become deserts in the near future. Rising seas and oceans will engulf low lying countries like Holland and Bangladesh. The Earth has warmed by 3 o C over the last century and is predicted to warm by 4 o C over the next 50 years. This is because of increases in CO 2 . How can we stop this ? Notes Diagram The greenhouse effect Polar ice caps Rising oceans

Effects of global warming one Scientists have many theories as to what may happen over the next century because of rising carbon dioxide levels in the a__________, as a result of combusting fossil fossils and the subsequent rising global temperatures. There is now increasing agreement amongst scientists that atmospheric carbon dioxide levels need to be controlled. Many countries have signed ‘ The Kyoto Agreement ’ which aims to reduce carbon emissions over the next 20 years. This will perhaps s____ global warming. Only one country, America has not signed up, she is the biggest carbon polluter. Why do you think that America has not signed up ? Effects of global warming: Science Interactive LTD Copyright 2005 Word bank: atmosphere slow Flooding will increase over the next decade. In England (summer 2004), we had some of the worst flash floods on record, including Boscastle. Flooding The destruction of the Ozone by CFCs from aerosols will also add to global warming by reflecting less infra red heat given out by the sun. Ozone layer Notes Diagram Average world or global temperatures are set to increase by between 0.5 and 1 o C per decade for the next fifty years. Global warming More extremes of temperatures are now expected with lower rainfall in areas which already see little rain over the year. Drought

Effects of global warming two The greenhouse effect is a natural process where the 750 billions tonnes of c________ dioxide in the atmosphere maintains the Earth’s atmosphere at hospitable temperatures, which are supportive of life, here on Earth. Combusting fossil fuels is adding to this ‘warming effect’ causing average global t___________ to rise over the last fifty years. Global warming will continue, whilst we continue to combust fossil fuels like coal and oil. The World’s weather, habitats and temperature are set to change over the next century. Effects of global warming: Science Interactive LTD Copyright 2005 Word bank: carbon temperatures The ice caps have shrunk in size over the last 30 years. This may rise sea levels and also reduce the amount of the Sun’s infra red heat reflected back into space. Melting ice caps Animals and plants may undergo mass extinction in the next one hundred years if global warming continues. The Malarial Mosquito is spreading north into Europe. Biodiversity Notes Diagram The World’s weather will become more dynamic. In summer 2004, Florida in America was hit by three hurricanes causing immense damage. Weather Damage due to strong tides and wave action along the coast will also increase over the next decade. Parts of the England's coastline are now being eroded. Waves

1: Define the following terms: Producers, Consumers, Top-predators, Food-web, Biomass, Energy-flow, Trophic-level, Greenhouse-effect & Biosphere . 2: Look at the diagram of the three types of organisms. Complete the table: 3: Match the following organisms with their habitats: 4: Complete: Producers like green plants are able to make their own ______________ by photosynthesis. These producers are fed upon by herbivores or ____________ consumers. These provide food for ______________ consumers: Dead and _____________ material provide nutrients for ______________ and fungi. These feeding relationships can be shown in a food chain or __________. Extension questions and homework Science Interactive LTD Copyright 2005 How are they adapted for their role ___________________________ ? _____________ ? Bacteria Rabbit, buffalo, sheep, Slug, Snail & ants Primary consumer Camel __________________________ ? _____________ ? Killer Whale Other examples Class Organism Wood Killer whale Pond River Ocean Rocky shore Wall Trout Squirrel Crab Heather Frog

5: Look at the information in the table below. It shows the relationship between the numbers of lynx and snowshoe hairs over the last 150 years: a) Explain the relationship between the numbers of lynx and snowshoe hares over the last 150 years. b) Why is there a delay in the response of lynx numbers to declining numbers of snowshoe hares.. c) Name two other prey – predator relationships. 6: Look at the food chain below and answer the questions: a) Name the producer. b) Name the secondary consumer. c) Name the top predator. d) Explain how energy is loss through each feeding level. e) Draw a food chain with five links in it. 7: a) Give 2 ways in which nitrogen in the form of nitrates can be added to the soil. b) How is nitrogen in the form of nitrates lost from the soil and what do plants use nitrates for during normal growth and development. c) What are the main effects of the greenhouse effect and how can we reduce its impact on global weather. Internet: Go to google.co.uk and find about the greenhouse effect. Also find out about how you can reduce you impact on the environment by using less fossil fuels. Science Interactive LTD Copyright 2005 Eagle 10 kJ Fox 100 kJ Rabbit 1,000 kJ Grass 10,000 kJ