does organism per capita energy increase or decrease as we go

[Smooth Operater]

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q: loss of energy is a crucial factor in the food chain, which is often considered as a pyramid. At lowest level of the pyramid are the organisms having the highest per capita energy which decrease as we move up. Which one of the following arrangements would represent the best pyramid of energy?

A: plants --> worms --> rodents, birds etc.. --> man

the question says highest per capita energy decreases as we move up, but I though man and mammal use more energy than worms??

 

[bionerd]

q: loss of energy is a crucial factor in the food chain, which is often considered as a pyramid. At lowest level of the pyramid are the organisms having the highest per capita energy which decrease as we move up. Which one of the following arrangements would represent the best pyramid of energy?

A: plants --> worms --> rodents, birds etc.. --> man

the question says highest per capita energy decreases as we move up, but I though man and mammal use more energy than worms??

No no no...the highest per capita energy doesn't refer to "who uses the most energy". It refers to amount of energy available for usage. There's lots of plants --> lots of energy. The the time the worms eat those plants, a lot of energy is lost through heat. So, when the rodents eat the worms, they're not getting 100% of the plant's energy, but maybe 70%. The rodents also loses energy through heat. So by the time man eats the rodents/birds, we get about 40% of the original supply of energy. Hence, it decreases as you go up the pyramid.

 

[whitethunder]

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