Populations

" There are too DAMN many people !!! "

Population ecology - The study of the number of a particular organism that is found in an area and why that number changes or stays fixed over time.

          Population - A group of organisms of a single species living in a particular area at a given time.

Population density - The number of individuals per unit area at a given time.

Range - The geographic limit of its distribution.

          Random Distribution - When individuals are spaced unpredictably (randomly).

          Uniform Distribution - The individuals are evenly spaced in the environment.

          Clumped Distribution - The individuals are clumped usually around some resource.

Population growth - Involves measuring increases/decreases in population size over time.

          Immigration - Move into an area

          Emigration - Move out of an area

          Natality    b - Birth rate

          Mortality    d - Death rate

Biotic potential - The maximum rate at which a population could increase under ideal conditions.

          Exponential growth - Population growing at its biotic potential. J shaped curve

Environmental resistance - Environmental conditions that limit a species from reproducing at its maximum rate.

          Carrying capacity - The largest population size that an environment can support over time.

          Logistic growth - S shaped curve. The population levels off under it's carrying capacity.

Predator-prey cycles - Offset Cycles. Each controls the others population size.

Sudden decline or Sudden death - Population growth greatly exceeds the carrying capacity and then there is a crash to 0.

Age structure - Graph of 3 age groups: Pre-reproductive, Reproductive, and Post-reproductive















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Last updated on 4 January 2018