Biology lab 4 alters and alters

First, what are two ecosystems that you studied?


The higher the tropic level, the smaller the population relative to the lower trophic level organisms. Higher trophic level organisms are usually larger. Larger animals need more resources than smaller organisms, so it's harder to sustain a larger population. Yeah?


If all the decomposers were eliminated, there would be nothing to recycle the dead and decaying materials and put nutrients back into the soil for the producers to grow. If there are then no producers in the ecosystem there is no way for energy to enter the system as well as no food for herbivores then once those die off there is no food for omnivores and carnivores, then nothing for the decomposers to break down for their energy and nutrients so they die and then there is simply nothing living left. Basically, if one part of the cycle is missing, it all falls to shambles.


I think so. There are bacteria (archaebacteria - aerobic thermophilic bacteria) that live at the bottom of the sea and have their own little ecosystem without carnivores and herbivores. They make simple sugars out of inorganic substances (like iron oxide [rust]), who needs herbivores!

No. Biology and the law of thermodynamics teach us that life must subsist on life; there is no single organism out there that does not feed on another type of life form, be it live or previously alive. Having said that, every life--and thereby the majority of components to an ecosystem-- are either herbivores or carnivores that subsist on other herbivores and/or carnivores.

What about decomposers? Can an ecosystem be comprised of solely producers and decomposers?

Good point Star. I guess it just depends on how broadly you want to define a herbovire and carnivore. For instance, an example of a decomposer still eats something else--be it a dead animal, insect, or plant, in which case, it is still eating flesh (a type of "meat") or the stuff that herbivores may eat. Producers also rely on other parts of their ecosystem, including producers and consumers that decompose into minerals that further provide plants with energy. See, the law of thermodynamics in which you cannot create or destroy energy means that for the producer to have enough energy, it must do so not only from the sun, but also from other life forms that have decomposed. But those life forms, as I argue above, subsisted on either flesh or plants, meaning that in the end, everything in the ecosystem is linked to herbivores and carnivores. Of course, you could surely come up with an ecosystem of only carnivores or only herbivorse, and those would still be self sustainable.