Section 7: Genetics, populations, evolution and ecosystems

Key Word test

What is the Hardy-Weinberg principle

A mathematical model that predicts allele frequencies will not change between generations if certain conditions are met.What are selection pressures?

What are selection pressures?

Environmental factors that limit the population of a species.

What is Sympatric speciation

Formation of new species in the same area due to reproductive isolation.

What is Allopatric speciation

Formation of new species due to geographical separation of populations resulting in reproductive isolation.

What is the definition of the term "directional selection"

Favours one extreme phenotype, shifting the population mean towards it.

What is adaptive radiation

One species evolves into different species adapted to different niches.

What is the definition of the term "directional selection"

Favours one extreme phenotype, shifting the population mean towards it.

What is Disruptive selection

Favours individuals with both extreme phenotypes and selects against those with phenotypes near the mean.

What is Genetic drift

A random change in allele frequency in a population due to chance, especially in small populations.