different types of natural selection Flashcards
(7 cards)
1
Q
What are the types of natural selection?
A
Directional and stabilising
2
Q
When does directional selection occur?
A
When there’s a change to the environment
3
Q
What is an example of directional selection?
A
Antibiotic resistance in bacteria
4
Q
What will happen over time with directional selection?
A
The mean will shift in a direction for the selection pressure
5
Q
When does stabilising selection occur?
A
When the environment remains stable
6
Q
Where does selection occur in stabilising selection?
A
Towards organisms with a phenotype closest to the mean
7
Q
What is an example of stabilising selection?
A
Birth weight in humans when selection occurs for an optimal range of birth mass
