Unit 1 Energy in Biomass

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  • Created on: 26-02-13 19:54

5.1 Pyramids of Biomass

Pyramids of Biomass

The source of all energy  is the sun the light is photosynthesised by plants and some algae. Biomass is the mass of living material in plants and animals that is built up by energy from the sun.

Some of this light energy is stored as chemical energy in Green plants which is passed through a food chain or food web.

A pyramid of biomass shows the amount of energy at each stage of the food chain.

The pyramid of biomass get shorter as it goes up because not all of the organisms are consumed by the level above, some of the energy is passed out as waste from the organisms and some energy is lost through other means. 

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5.2 Energy transfers

Energy Transfers

The biomass lessens as you go up the food chain because;

Ø  Herbivores cannot digest all of a plant. Undigested parts are removed from the body through faeces.

Ø  Animals and plants respire loosing energy through breathing and photosynthesis.

Ø  Animals and plants lose energy through growing.

Ø  Movement of animals takes away a large amount of energy because it transfers to kinetic + thermal energy.

Ø  Plants, animals use energy to keep their bodies at the same temperature.

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5.3 Decay Processes

Decay Process - The Decay Process

The decay process is when animals and plants recycle nutrients. E.g. Tree's leaves fall or an animal dies and organisms called decomposers will break down the waste and dead animals and plants and then return the nutrients to the environment.

Decomposers are made up of fungi and bacteria;

1.     Detritus feeders such as maggots eat dead animals and plants and their waste is digested by the bacteria and fungi.

2.     The waste products of decomposers are water and carbon dioxide which can be used by plants to photosynthesise.

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5.3 Decay Processes

The conditions;

·  Warm temperature - because decomposers will slow/freeze if too cold or denature if it’s hot.

·  Moist conditions - as this will make it easier to dissolve food and prevents them from drying out.

·  Oxygen rich - as most micro-organisms need to respire to grow and reproduce.

No decay = Earths resources ran out years ago.                                                      

We use micro-organisms in sewage treatment because they break it down, making it safe. Compost heap(grass cuttings, vegetable peelings etc.) can be broken down and used as fertiliser

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5.4 Carbon cycle

The Carbon Cycle

The amount of carbon on Earth is fixed and some carbon is locked up in fossil fuels, oil, coal and gas and is only released when burned. When carbon is released and locked up we call this the carbon cycle.

Green plants photosynthesise and use the carbon in CO2  to make carbohydrates, fats and protein. The carbon is passed onto animals when they eat the plant. This is how carbon is taken out of the environment.

Living organisms respire, this break down glucose with oxygen to produce energy in their cells and carbon dioxide is released as a waste material.

Detritus feeders break down dead animals and respire at the same time.

Combustion - something is burned with the presence of oxygen and when coal, oil or gas is burned, carbon dioxide is produced from the locked up carbon in the fossil fuels.

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5.5 Recycling organic waste

 Organic waste;

·         waste vegatables

·         peelings

·         grass cuttings

·         tree clippings

Organic waste composted in several ways;

·         Most efficiant method: Mixture of moisture and oxygen.

o    Some farmers may add detitovores (e.g. worms, wood lice)

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