Molecular Evolution Flashcards
Define natural selection
The effects of a wide range of factors on the frequency of heritable changes in a species
Define what is meant by the term “fitness”
How well a species is able to reproduce in its environment.
(Anything that increases fitness is selected for and anything that decreases fitness is selected again)
What is the main source of heritable changes in species?
Genetic variation
What factors are Frequencies of genetic variation effected by?
- selection
- mutation
- migration - genetic drift
Give some examples of positive selection due to genetic variation.
- resistance to disease
- ability to metabolise a new food source
- antibiotic resistance
- changes in appearance that enhances mate choice
What parts of the genome are resistant to change?
The parts of the genome that contain vital sequences are conserved.
What is a mutation?
The name for the process by which variation in the genome arises is mutation.
What causes there to be a rare variant?
- may have arisen very recently
- deterioration (harmful) and being selected against
- or both
Define Migration
The physical movement of people from a different population results in new pools of variants being introduced to an existing population (admixture).
Define genetic drift
The frequency of a variant changes in a population due to chance.
All variants are subject to genetic drift.
