Ecology Notes Can’t we all just get along?

Population Density  The total number of individuals living in a specific area  Example person/km2

Population Distribution  Random  Clumped  Uniform

Gains and Losses in Population Size  Immigration- Organisms that move into a population  Emigration- Organisms that move out of a population

Gains and Losses in Population Size  Mortality-similar to death rate; the number of organisms that have died  Natality- birth of organisms

Population growth  How would you calculate growth rate of a population? Immigration – emigration + births - deaths

Exponential Growth/Doubling Time  Exponential = Growth that occurs very rapidly p x  Doubling time = time it takes for a population to double “rule of 70”  All populations go through an exponential growth stage but some rely on it and are called r-selected life strategists

Biotic Potential  The rate at which a population could grow if nothing was holding it back, no limits  What are the limits or “Limiting factors” –space, light, water, nutrients, and shelter

Carrying Capacity  The maximum limit a population can hold in a given environment.  Most organisms follow this and it follow this and it is called a is called a k-selected life k-selected life strategy strategy

How Density Relates to Factors  Density Dependent Factors –Factors that come into effect with population size  Populations will grow to their capacity but are dependent upon outside factors –Food, water, space, sunlight  Density Independent Factors – Factors that come into play regardless of population size  Natural disasters (hurricane, flood, volcano) war Where would disease fit?

Life History Patterns  Type I –Humans / Elephants –Few offspring/life longer  Type II –Jellyfish / Birds –Constant Death rate  Type III –Oysters / Plants / Insects –High offspring-few live to reproduce

How did we get so big?

What will happen in the future?  Density Dependent Factors?  Density Independent?