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Basic Ecology 5
Evolution, adaption, exntinction, types of species
Question | Answer |
---|---|
habitat fragmentation | break ecosystems into small parts, may be too small to support populations of some species (grizzly bears require large territories), to resolve, make wildlife reserves/parks larger and/or establish migration corridors |
reestablishment of a community/habitat after it has been altered | restoration |
Reasons to protect endangered species | may be useful to humans in the future (medicines, etc.), ecological value (disappearance of one will affect other species), intrinsic/moral value (has right to live) |
common traits of endangered species | long lived, low reproductive rate, high on food chain, economic value |
natural process sped up by humans (mass extinctions = lots in a short period of time), causes typically habitat destruction, poaching, introduced species natural disaster | extinction |
endemic (naturally occur) in an ecosystem | native species |
species whose existence is critical to maintenance of ecosystem | keystone species |
species that serve as early warnings that an ecosystem is being damaged | indicator species |
species speciates into several others to fill vacant niches (ex. Darwin’s finches with different beak sizes on Galapagos Islands) | adaptive radiation |
Islands and species relationship? | tend to have fewer species than mainland, number of species on an island depends upon its size and distance from mainland |
when species in two different areas look alike | convergent evolution |
populations of the same species diverge into two new ones | divergent evolution |
two species arise from one, steps include geographic and then reproductive isolation | speciation |
initial establishment of communities in an area of bare rock | primary succession |
first species to appear in primary succession such as lichens, moss | pioneer species |
reestablishment of vegetation in an area following a disturbance | secondary succession |
final stage in ecological succession, stable, highest species diversity, only change back to earlier stage due to fire, severe storm, logging, etc. | climax community |
factors in environment which affect species survival and reproduction | selective pressures |
traits that better allow an organism to survive and reproduce | adaptations |
proposed by Charles Darwin, 3 conditions for evolution to occur by natural selection are variability for trait must exist in population, trait must me heritable, and trait must lead to differential reproductive success | natural selection |
theory regarding how populations change over time, refers to a change in population’s gene pool over time | evolution |