What Regulates Population Growth?

Abiotic: Physical Factors

Biotic: Density-Dependence

Density-Vague Regulation

Discrete Generation Growth

Model Characteristic

Density-Independent

Geometric Growth

Density-Independent

Geometric Mean Growth

Density-Dependent Growth

Biotic Regulation

• Density-Dependence

• Individual-Level, Birth and Death– Depends on Population Size

• Driven by Ecological Interactions

Self-Regulation

• Species Growth Responds to Own Density

• Intra-specific Competition

• Limiting resource(s)

dN/dt = F(N) N

Glycine soja (soy bean)

Tribolium confusum (flour beetle)

“ – 3/2 Rule”

Drosophila melanogaster

Melospiza melodia (song sparrow)Seed Production

Logistic Growth

Brewer’s yeast

Tasmanian sheep

References

• http://jan.ucc.nau.edu/~doetqp-p/courses/env470/Lectures

• http://www.micro.utexas.edu/courses/levin/bio304