Genetic Diversity and Adaptations

Question 1

Gene pool model of natural selection (6 steps)

Answer 1

1. DNA mutation = new allele of a gene
2. genetic variation leads to phenotypic variation within the population
3. selective pressure from biotic/abiotic change
4. individuals with favourable phenotype have selective advantage so survive and reproduce
5. inheritence of favourable allele by some offspring
6. frequency of favourable allele increases in gene pool

Question 2

directional selection

Answer 2

occurs when favourable individuals express one extreme of a phenotypic range, which shirfts the frequency distribution and mean for the phenotypic characteristic in one direction

Question 3

diversifying selection

Answer 3

selection favours individuals with extreme phenotypes and individuals with intermediate phenotypes are selected against, therefore the frequency distribution remains the same but the population becomes bimodal

Question 4

natural selection

Answer 4

selection against non-favourable characteristics, resulting in species better adapted to their environment

Question 5

genetic diversity

Answer 5

the number of different alleles of genes in a population

Question 7

example of stabilising selection

Answer 7

human birth weights

Question 8

example of directional selection

Answer 8

antibiotic resistance

Question 9

3 types of adaptations that can occur from natural selection

Answer 9

1. anatomical
2. physiological
3. behavioural

Question 10

how does extinction occur?

Answer 10

if environmental changes occur too rapidly, species may be unable to adapt and change to survive, so go extinct