1. Population Ecology

2. What is a population? All the members of a species living in the same place at the same time. Organisms usually breed with members of their own population.

3. How to describe populations Density: number of individuals per unit area, or volume. Ex. Number of deer/km 2. Dispersion: The distribution or arrangement of individuals in space. Dispersion may be clumped, even or random.

4. Growth Rate A change in the size of a population over a given period of time = growth rate. Growth rate = births – deaths Populations usually stay about the same size from year to year as factors kill many individuals before they can reproduce.

5. How fast can a population grow? Reproductive potential: The maximum number of offspring that each member of a population can produce. Some species have much higher reproductive potential than others.

6. How many bunnies? Rabbits can begin reproducing at 4 - 6 months Gestation is 31 days Litters can be up to 14 Females can become pregnant within hours of giving birth Lifespan is about 7 years 95 billion rabbits in 7 years!

7. Exponential growth Occurs only when there is enough: Food Space Little or no competition No predators Populations rarely grow at their reproductive potential

8. Carrying Capacity Carrying capacity is: the maximum population that an ecosystem can support indefinitely. Ecosystems change so carrying capacity is difficult to predict or calculate precisely.

9. Resource Limits A species reaches its carrying capacity when it consumes a natural resource at the same rate at which the ecosystem produces the resource. This resource is called the limiting resource. Examples include: light, nutrients, water.

10. Density Dependent Population Regulation Deaths occur more quickly in a crowded population. Limited resources, predation and disease result in higher death rates in dense populations. Ex. Emerald Ash Borer possibly going to invade Iowa

12. Density independent A certain proportion of a population dies regardless of population density. Ex. Severe weather