Evolution: Drift and Selection Flashcards
What are the five key causes of evolution?
Small population Non-random mating Mutations Gene flow Adaptation
What is evolution?
The change over time in the proportion of individuals in a population differing in one or more inherited traits.
What is a random process?
Genetic drift
What are non-random processes?
Natural selection and sexual selection
How does variation in traits arrive?
Through mutations.
What is the original source of new DNA sequences?
Mutation
What happens to individuals better suited to the environment?
They tend to survive longer and produce more offspring, breeding to pass on alleles which are beneficial to the next generation.
What does selection result in?
The non-random increase in the frequency of advantageous alleles and the non-random decrease in the frequency disadvantageous alleles.
What is sexual selection?
The non-random process involving the selection of alleles that increase the individual’s chance of mating and producing offspring.
What may sexual selection lead to?
Sexual dimorphism.
What can sexual selection be due to?
Male-male rivalry and female choice.
What is male-male rivalry?
Large size or weaponry increases access to females through conflict.
What is female choice?
It involves females assessing the fitness of males.
When does genetic drift occur?
When chance events cause unpredictable fluctuations in allele frequencies from one generations to the next.
Why is genetic drift more important in small populations?
As alleles are more likely to be lost from the gene pool.
