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Published byMarcia McLaughlin Modified over 9 years ago
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Predator vs. Prey prey impacts predator population more hunters kill 500,000 deer/year predators switch prey instead of starve Act. 1 – lynx and hare Act. 2 – pike and perch
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Population density/distribution (14.3, pgs. 436-439) population density – how many organisms live in a defined area
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clumped dispersion uniform dispersion random dispersion population dispersion – how the population is spread out Population density/distribution (14.3, pgs. 436-439) clumped – for mating, protection, or food spot uniform – territory and food competition
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Population density/distribution (14.3, pgs. 436-439) clumped uniform
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Population density/distribution (14.3, pgs. 436-439) Type I – big mammals (black bear) few young (1-3), lots of care Type II – small mammals, birds, rabbits more young (4-12), less care Type III – insects, parasites thousands of young, no care
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Population density/distribution (14.3, pgs. 436-439)
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Population growth patterns (14.4, pgs. 440-444) Factors that affect populations: 1.immigration – species moving in 2.emigration – species moving out 3.birth rate – goes up when habitat is good 4. death rate – goes down when habitat is good
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Population growth patterns (14.4, pgs. 440-444) exponential growth – rapid population growth due to abundant resources (pennies) J-curve Australia: 24 were brought in 1859 for sport hunting, but enough food, and no good predators = 200-300 million today
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Population growth patterns (14.4, pgs. 440-444) logistic growth – slow growth, then exponential growth, then level off due to resource limits S - curve
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Population growth patterns (14.4, pgs. 440-444) carrying capacity - average # supported by an ecosystem; environment quality can change capacity population crash - dramatic decline when above carrying capacity weather related possibly fire new species that messes things up
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Population growth patterns (14.4, pgs. 440-444) limiting factors – factors that keep population down 1.density-dependent factors: are affected by the population of individuals; when above capacity competition, predation, parasitism and disease, starvation 2.density-independent factors: not related to population; can happen anytime unusual weather, natural disasters, human activity
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