9.3+ 9.4 genetic diversity and selection

Question 1

genetic diversity

Answer 1

total number of different alleles in a population

Question 2

population

Answer 2

group of individuals of same species that live in same place and can interbreed

Question 3

Greater genetic diversity

Answer 3

The wider the range of alleles, the wider range of characteristics, the greater the probability an individual possesses a characteristic that suits environmental conditions

Question 4

natural selection in evolution of popn

Answer 4

only certain individuals reproduce successfully(competitive survival) and pass on their alleles, so not all alleles of a popn are likely to be in next generation

increases this allele frequency

Question 5

2 types of selection

Answer 5

1. directional
2. stabilising

Question 6

selection

Answer 6

process by which organisms that are better adapted to their environment tend to survive and breed, while those that aren’t don’t

Question 7

directional selection

Answer 7

• if environmental conditions change, phenotypes of a species that are best suited are more likely to survive and breed
• these individuals fall to either side of the characteristic mean(normal distribution curve)
• they will therefore contribute more offspring and alleles to next gen with this advantageous phenotype
• over time, mean moves in direction to these individuals

Question 8

stabilising selection

Answer 8

• if environmental conditions remain stable, individuals with phenotypes closest to mean are favoured
• these individuals pass alleles onto next generation, and individuals with phenotypes at extremes are less likely, becoming eliminated