3.5 Population Growth and Resource Avaliability

Size (N)

Total number of individuals in a given area in a given time

Larger = safer from population decline

Density

number of individual/area

High Density = higher competition, possible disease outbreaks and depletion of food sources.

Distribution

How individuals in a population are spaced out compared to each other

Random Distribution

Trees

Uniform Distribution

territorial animals

Clumped Distribution

group animals

Sex Ration

50/50 male to female - mating conditions

• die off or bottleneck affect can skew this

Density - Dependent Factors

Factors that influence population growth based on size

Ex. food, competition for habitat, and water

Density - Independent Factors

Factors that influence population growth independent of their size

Ex. natural disasters

Biotic Pontential

max. potential growth rate with no limiting resources

• exponential

• eventually exceeds K then a die off occurs

Logistical Growth

initial rapid growth, then limiting factors limit population

Population Size Formula

(immigration + births) - (emigration - deaths)

Percent Change Formula

100 * final - initial / |initial|