So here we have an example problem that asks what will eventually happen to all of an ecosystem's incoming energy? And we've got these 6 potential answer options down below. Now, option A says it will be used in photosynthesis. And at first, this might seem like a tempting correct answer option, but it's not actually correct. And that's because much of the incoming energy will actually be reflected and won't actually get captured and absorbed and used in photosynthesis.
Additionally, not all ecosystems on Earth are going to rely on photosynthesis to capture their energy. For example, ecosystems that are deep under the ocean and don't receive any sunlight at all may actually rely on organisms that perform chemosynthesis by obtaining energy from hydrothermal vents. And so that's another reason we could have eliminated answer option A. Now moving on, option B says it will be transferred to decomposers. But we know that with every single energy transfer, there's going to be some energy lost in the form of heat.
And so not all of the energy is going to be capable of being transferred to the decomposers for that reason. And so that's why we can eliminate option B. Now option C says it will be transferred from one trophic level to the next. But once again, we know that with every single transfer of energy, there's going to be some amount of energy lost in the form of heat. So not all of the energy will be able to be transferred from one trophic level to the next, and that's why we can eliminate answer option C.
So now we're between either option D, E, or F. And notice that option E says that all of the ecosystem's incoming energy is going to get continuously cycled, but we know from our previous lesson video that this is not going to be true, that, because energy is going to be continuously lost as heat, this causes energy to flow through the ecosystem in one direction and it's not going to be recycled for any extended period of time. So for that reason, we can eliminate answer option E and notice that answer option D says it will be dissipated as heat and this is going to be the correct answer. All of an ecosystem's incoming energy will eventually be dissipated as heat. So we can indicate that D here is the correct answer and of course this means F is not going to be correct.
None of these options are true because we know option D is true. So that concludes this problem. I'll see you in our next video.