Populations: Variation and Selection

Individuals in a species population exhibit phenotypic variation due to genetic and environmental factors.
The main source of genetic variation is mutation.
Meiosis and random gamete fertilisation during sexual reproduction create more genetic variation.
Predation, disease, and survival competition lead to natural selection, i.e. differential survival and reproduction.
Organisms with phenotypically advantageous traits likely produce more offspring, passing beneficial alleles to the next generation.
Differential reproductive success influences allele frequencies within a gene pool.
Stabilising, directional, and disruptive selection also affect these frequencies.
Evolution is portrayed as a shift in a population’s allele frequencies.
A comprehensive model explaining evolution and natural selection is necessary and can be modified for different concepts.
Practice papers are highly recommended for a thorough understanding.