# Science resit- Energy Transfer and Energy Flow

Notes on Energy Transfer and Energy Flow

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## Energy

Organsims need to get their energy from somewhere.

Producers capture their own by photosynthesis.

Everything else had to eat to get it.

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## Energy from the sun

Energy from the sun is the source of enrgy for nearly all life on earth.

Plants- use a small percenatge of the light energy from the sun to make food during photosyntheisis. This energy then works it's way through the food chain as animals eat the plants and each other.

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## Energy lost

The energy lost at each stage is used for staying alive. (respiration)

Most of the energy is lost to its surroundings as heat. (mainly in mammals and birds as they need to keep a constant temperature whcih is normally higher than their surroundings)

Material and Energy is lost from the food chain as waste products. Egestion is when food that can't be digested passes out as faecas.

Waste products and uneaten parts can become starting points for other food chains. House flies eat faeces.

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## Why only 5 Throphic levels

So much energy is lost at each stage that there's not enough left to support more organisms after four or five stages.

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## Calculating Efficiency

Efficiency = (energy available to the next level) / (energy that was available to the previous level) X100

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## Interpret data and energy flow

The numbers show the amount of energy available to the next level.

So 80000KJ is the amount of energy available to the greenfly, and 10000KJ is the amount available to the ladybird.

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## Energy loss in food chains

You can work out how much energy has been lost at each level by taking away the energy that is available to the next level from the energy that was available from the previous level.

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