Competition ESE 2010

I. Population size A. Population density- # of individuals that live in a given area B. Growth Rate 1. exponential growth curve a. rate of population growth remains the same b. result is a steady increase over time 2. logistic model a. growth is limited b. shows density-dependent factor 1.) limited resources like food and water

C. Birth and Death 1. rates can go up and down. a. death rate – how many die 1) aka mortality rate 2) may be old age, disease, hunting, destruction of ecosystem etc b. birth rate- how many are born 1) aka natality 2) more offspring are born than can survive

D. Migration 1. immigration- new species move in 2. emigration – species moves out 3. Most populations are open populations where individuals may move in and out.

C. Depends on limiting factors: 1. Reproductive potential 2. Carrying capacity of the environment a. Limited resources 3. Environmental resistance a. Disease b. Weather c. Density of population d. Predation e. Anything with a negative effect on a population

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Predator/Prey Relationship

II. Competition in Ecosystems A. Organisms compete for 1. food 2. resources 3. space 4. mating rights 5. territory B. The best survive: Natural Selection

C. Niche- What an organism does; its job 1. decomposer, food source, filter feeder, etc 2. Animals avoid some competition by filling a particular niche a. hawks hunt in day, owls at night b. certain plants live in shade, others in direct sunlight

D. Nonnative species 1. Sometimes species that do not belong are introduced into new ecosystems a. can have negative effects on the ecosystem b. become invasive 1) mongoose introduced to kill snakes c. can invade by themselves, but humans are usually the cause