1
Q
What is genetic diversity?
A
- NO° of diff alleles of genes in a pop
- allows natural selection to occur
2
Q
What does natural selection lead to?
A
- evolution in populations as species become better adapted to their envi
- adaptations may be anatomical, physiological or behavioural
3
Q
What is evolution?
A
- change in allele frequency over many gens in a pop
4
Q
Explain how natural selection could lead to evolution within a pop. (Principles of natural selection)
A
- random mutations cause new alleles of a gene
- if new alleles inc chances of individual to survive in that envi, they’re more likely to survive + reproduce
- this advantageous allele is passed on/inherited by members of next generation
- as a result, over many gens, new allele inc in frequency in pop
5
Q
What is directional selection?
A
- when 1 of extremes has selective advantage
- occurs when there’s a change in envi
- modal trait changes
- e.g. antibiotic resistance in bacteria
6
Q
What is stabilising selection?
A
- modal trait has selective advantage so remains same
- occurs when there’s no change in envi
- standard deviation dec as individuals w extreme traits dec
- e.g. human birth weights
