BIOLOGY 1B Lecture 22: Bio 1B 3-10
Document Summary
->primary consumers: herbivores, elk, moose, some feed on larger plants, some on smaller plants. ->dominant species: species with greatest population in an area. ->keystone species: organisms that have a big impact on the ecosystem out of proportion with their numbers (such a wolves-->on elk, then plants) ->very complex relationships, demonstrates features of food webs. ->have to do directly with who"s feeding on whom. ->not directly through feeding relationships, but like wolves and plants (fewer wolves=more elk=less plants) ->impacts of invasive species: chain of reactions going through entire food web. ->wolves: presence or absence controls much of what happens down the food chain-->thus it is a keystone species. ->other keystone species have top-down effects as well. ->we start with some energy, separate it according to whether it is accessible to organisms or not. ->start with a lot of sun"s energy, used by primary producers, some goes on to next level-->primary consumers.
