Keystone species: keystone predators and ecosystem engineers (exam 4)

autogenic ecosystem engineers

- change the environment using parts of their own physical bodies (both living and dead). As these organisms grow, they create habitat for other species. -corals

keystone predator

-a top carnivore selectively feeds on a number of potential competitors on lower trophic levels, lowering their population size. -a predator species that reduces the density of the strongest competitors in a community, thereby helping maintain species diversity

allogenic ecosystem engineers

-change the physical environment by transforming living and nonliving materials into another state. -by cutting down trees and building dams and it creates a habitat for animals -elephants migrate and cut down trees turning woodlands into grasslands -humans

keystone species

-has a disproportionately large effect to the structure, composition or function of a community or ecosystem -A species that influences the survival of many other species in an ecosystem

trophic cascade

A series of changes in the population sizes of organisms at different trophic levels in a food chain, occurring when predators at high trophic levels indirectly promote populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check. Trophic cascades may become apparent when a top predator is eliminated from a system.

a top carnivore reduces what from happening

competitive exclusion from occurring and the potential extinction from predation effects among the lower trophic level consumers

Robert Paine

described keystone species

what is an important line of evidence pointing to the potential of a species to be a keystone predator

if it is in a trophic cascade following the removal or reintroduction of the species question

the impacts are _____ large relative to the keystone species

in proportional

what happens if many top predators are eliminated

it can destabilize a community, causing a trophic cascade down the food web, reducing species diversity and it can affect the abiotic environments in complex ways

what species are least likely species to be considered "redundant" in their communities

keystone species

when a species is removed the community is ____ species rich and ___ in structure

less and simpler

real liked example of keystone species

page 131 and 132

by reestablishing a keystone predator is often ___ the effects of the reduced community richenss

reverses

what are some well examples of keystone species

sea stars, bears, wolves, and other organisms

how many types of keystone species are there

several

ecosystem engineers

a keystone species that creates, maintains, or destroys habitat for other species- which in turn effects the species diversity and habitat heterogeneity of the environment

what are the two types of ecosystem engineers

allogenic and autogenic