Natural Selection and Evolution

Evolution

The gradual change in inherited traits of a population over many generations.

What is natural selection?

The process where environmental factors act on a population.

What is the result of natural selection?

Some organisms have a greater chance of survival than others.

Population

All organisms from the same species in a particular area.

Community

A group of populations (multiple species) in an area.

Ecosystem

A community of living organisms interacting with each other and their environment.

Biotic Factors

Living components such as fish, mammals, plants, and disease.

Abiotic Factors

Non-living components such as wind, light, water, and shelter.

Selection Pressures

Biotic and abiotic factors that affect an organism's behaviour, survival, reproduction, and habits.

Structural Adaptation

Physical feature of the organism, such as a kangaroo's powerful legs for hopping.

Behavioural Adaptation

How the organism behaves, such as penguins huddling together to stay warm.

Physiological Adaptation

How the organism's body works, such as a chameleon changing pigment production to alter colour.

Microevolution

Small-scale variation of allele frequencies within a species where descendants remain the same species.

Macroevolution

Variation of allele frequencies at or above the species level, resulting in speciation.

Gene flow

Movement of alleles between populations due to movement of individuals.

Genetic drift

Random events that cause change in allele frequency such as births and deaths.

Mutations

Changes in DNA that act as a source of new alleles.