Population size, density, growth rate, and dispersion
- Population Size – The number of individuals in a population
- Population Density – The number of individuals that live in an area (Population size/area)
- Growth Rate: Birth Rate – Death rate = Growth Rate
- Dispersion – The ways individuals of a population spread
- Density Dependent Factors – Limited Resources whose rates of depletion depend on the density of the population using them – Food, Water
- Density Independent Factors – Factors unaffected by density that affects the growth of populations – Climate, Geography
- Carrying Capacity (K) – The number of individuals in a population that an environment can hold
- Population Models- Hypothetical populations that attempt to exhibit the key characteristics of a real population
- Exponential Models- “J” shaped curves showing a rapid increase in population size
- Logistic Models- The population in which exponential growth is limited by density dependent factors
- R-strategists – An opportunistic population where the population density fluctuates, usually in open habitats with little competition
- K-strategists – A population in equilibrium; its density hovers near carrying capacity
- R-Strategists: Maturation Time- Short, Lifespan- Short, Death Rate- Often high, Number of Offspring per Episode- Many, Number of Reproductive Episodes per Lifespan- Usually one, Time of First Reproduction- Early in Life, Size of Offspring- Small, Parental Care- None
- K-Strategists: Maturation Time- Long, Lifespan- Long, Death Rate- Usually Low, Number of Offspring per Episode- Few, Number of Reproductive Episodes per Lifespan- Several, Time of First Reproduction- Later in Life, Size of Offspring- Large, Parental Care- Extensive