Adaptation and Taxonomy Flashcards
What happens to the mean in directional selection?
It moves in the direction of the favourable extreme
What happens to the mean in stabilising selection?
It remains the same as the populations loses its extremes and stabilises
What does directional selection favour?
Extremes
What does stabilising selection favour?
Middle range
What causes directional selection?
An environmental change
What happens in response to directional selection in response to an environmental change?
Only individuals with favourable extreme characteristics can survive and reproduce and therefore pass on the allele for the favourable characteristic
Why does stabilising selection stabilise?
Because extreme individuals cannot survive, reproduce and pass on their alleles to future generations
Give an example of stabilising selection
Birth weight
Give an example of directional selection
Antibiotic resistance
What is genetic diversity?
The number of different alleles of a gene in a population
What does a larger gene pool indicate?
Greater genetic diversity
What does natural selection result in?
Species being better adapted to their environment
How can a species adapt to its environment?
Anatomically, Behaviourally, Physiologically
How does natural selection take place?
Individuals with beneficial alleles and phenotypes are more likely to survive, reproduce and pass on the beneficial alleles to the next generation
What is evolution?
The change in allele frequency over time
