Why is the flow of energy unidirectional?

Answer 1

Energy flowing through a system has to come from somewhere and has to go somewhere because there are two laws of Physics that apply.

1. Energy can nether be created nor destroyed only changed - transformed.
2. Any time you make an energy transformation, some of the starting energy is going to be lost as heat.

In the Biosphere the source of energy is the Sun, sunlight. This is trapped and stored by plants (producers). As plants use this energy to live and grow, they give of heat (as per law 2) so the Sun's energy is transformed.

Then along come animals that eat plants and steal the plant's food stores, these animals have to be more active than plants so, as they live and move, these too give of heat. More of the Sun's original energy is lost (as per law 2).

The plant eaters are then predated by carnivores, the carnivores steal the herbivore's food stores and use it to live and move and these too give off heat. More of the Sun's original energy is lost (as per law 2).

Thus you can see that the process of life can be looked at as a flow of energy from organism to organism with this energy gradually being lost (into space) as heat. High quality energy (visible light) straight from the Sun is transformed into low quality energy (heat) by living things.

The second law means that you can not turn low quality energy into high quality energy and this make the path of energy transformation uni-directional.

Answer 2

ITS BECAUSE

……….An energy pyramid's shape shows how the amount of useful energy that enters each level - chemical energy in the form of food - decreases as it is used by the organisms in that level. How does this happen.Recall that cell respiration "burns" food to release its energy, and in doing so, produces ATP, which carries some of the energy as well as heat, which carries the rest. ATP is then used to fuel countless life processes. The consequence is that even though a lot of energy may be taken in at any level, the energy that ends up being stored there - which is the food available to the next level - is far less. Scientists have calculated that an average of 90% of the energy entering each step of the food chain is "lost" this way (although the total amount in the system remains unchanged).The consumers at the top of a food pyramid, as a group, thus have much less energy available to support them than those closer to the bottom. That's why their numbers are relatively few in most communities. Eventually, the amount of useful energy left can't support another level. That's why energy flow is depicted in the shape of a pyramid. The energy that enters a community is ultimately lost to the living world as heat.

Answer 3

cheese