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what are the factors towards human population growth
more food (ind. rev.), food distribution (transport systems), and less infant mortality (water, healthcare)
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what do population histograms do
examine population of organism in terms of age and proportion of males and females
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what is growing population histogram
wide base, higher percentage of young offspring
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what is stable population histogram
young > adults, pop. grows slowly
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population decline histogram
base of pyramid is narrower than middle
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interspecific competition
competition between different species, restricts population growth
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interference competition
aggression for the same resource
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exploitative competition
consumption of shared resources, in relation to ecological niche
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what are the results of interspecific competition?
population size that is weaker decreases, species could change behaviour, populations could migrate
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what is gause's principle (competitive exclusion)
if 2 populations of orrganimss occupy same ecological niche in same evironment, one population will be eliminated
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what is coevolution
2 different species exert selective pressures on each other
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what are the 2 types of defense mechanisms
- passive - prey hiding
- active - flee from predators
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population cycles
when organisms exhibit regular population fluctuations of growth and decline
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commensalism
one benefits, the other neutral
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mutualism
both species benefit
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example of social parasitism
ant invades other colonies and steals cocoons
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what is the difference between primary and secondary succession
- prmary - no community at the beginning
- secondary - an established community before destructive event
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what is the order of the phases blah blah succession
pioneer, seral/intermediate, climax
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