genetic diversity

genetic diversity?

number of different alleles of genes in a population

natural selection?

process that leads to evolution

can only take place if genetic diversity present

evolution?

change in allele frequency over many generations in a pop.

what are the types od adaptations?

anatomical

physiological

behavioural

process of natural selection?

• variation exists via random mutations

• new alleles that increase chance of survival have selective advantage

• those with the allele are more likely survive and reproduce

• passing on their advantageous allele

• over gens, frequency of this allele increases in the population

what are the 2 types of selection?

directional

stabilising

directional selection?

• when a change in environment occurs

• one extreme trait has selective advantage

• those with this trait more likely to survive + reproduce, increasing frequency of organisms w/ allele for extreme trait

• mean trait value shifts towards the extreme

stabilising selection?

• most common traits have selective advantage

• no change in environment

• those with these traits more likely to survive + reproduce so mean trait stays the same

• standard deviation decreases as no. individuals w/ extreme trait decreases; less variation around the mean

how to measure in genetic diversity?

• compare base sequence DNA/mRNA, amino acid sequence, or frequency of measurable observable traits

• greater difference = more distantly related, as mutations build up over time

• (more mutations = more changes in amino acid sequence)

population?

group of same species organisms in a particular space at a particular time

that can produce fertile offspring

important of GD?

enables natural selection

• new allele may be favoured

• beneficially changing polypeptide chain coded for

• allowing selective advantage