Population Dynamics Characteristics of a population Geographical distribution

Population Dynamics

Characteristics of a population • Geographical distribution – Describes area inhabited by population • Density – The # of individuals / area • Growth Rate – The change in # within a population due to births, deaths, immigration, & emigration • Age Structure

Exponential Growth • Occurs when individuals in a population reproduce at a constant rate • Under ideal conditions with unlimited resources, a population will grow exponentially

Logistic Growth Occurs when resources become less available (Slows population growth rate) Slow population growth rate due to 1. Decrease in birthrate 2. Increase in deathrate 3. Immigration decreases 4. Emigration increases

Carrying Capacity The largest # of individuals an environment can support

Limits to population growth Limiting Factor – causes population growth to decrease • • Density Dependent Limiting Factors which work best with a large dense population Interspecific competition Intraspecific competition Predation Disease Parasitism Density Independent Limiting Factors Tornado, hurricane, drought, temperature Human disturbance (Clear-cutting forests or damming rivers)

Competition Competitive exclusion principle • No two species can occupy the same niche in the same habitat at the same time • Interspecific competition occurs between two species for similar resources • Intraspecific competition occurs within a species for similar resources