ECOSYSTEM ORGANIZATION And POPULATIONS OVERVIEW

Ecosystem Organization Population is the number of individuals of the same species in the same place at the same time.

Factors That Control Population Growth What determines the population number of an ecosystem (or planet)? (Think in terms the basics that plants, animals and ourselves need to survive.)

Limiting Factors An environmental factor that causes a population to decrease Food Water Space Weather 4

Other Factors That Control Population Growth Other Limiting Factors: Competition Predation Parasitism Crowding Stress Disease

Carrying Capacity The largest population that an area can support A giraffe must eat 10 kg of leaves each day The trees in an area can provide 100 kg per day while remaining healthy Could 15 giraffes live in this area? What is the carrying capacity? 6

What dynamics might be involved in predicting population growth? Population Size Population Growth Rate Carrying Capacity Limiting Factors

Population Growth Curves Exponential growth: Population increases by a constant proportion per unit of time At this growth rate the population exhibits a J-shaped curve Time Population Exponential B Lag A

Population Growth Curves Logistic growth: Population increases rapidly for a period of time, its growth begins to slow, and ultimately, growth stops. At this growth rate the population exhibits an S-shaped curve. K (carrying capacity) = maximum population size that an environment can support Time (in days) Population K K carrying capacity lag exponential stabilization