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

Population density/distribution (14.3, pgs ) population density – how many organisms live in a defined area

clumped dispersion uniform dispersion random dispersion population dispersion – how the population is spread out Population density/distribution (14.3, pgs ) clumped – for mating, protection, or food spot uniform – territory and food competition

Population density/distribution (14.3, pgs ) clumped uniform

Population density/distribution (14.3, pgs ) 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

Population density/distribution (14.3, pgs )

Population growth patterns (14.4, pgs ) 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

Population growth patterns (14.4, pgs ) 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 = million today

Population growth patterns (14.4, pgs ) logistic growth – slow growth, then exponential growth, then level off due to resource limits S - curve

Population growth patterns (14.4, pgs ) 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

Population growth patterns (14.4, pgs ) 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