8/ natural selection

Question 1

3 conditions for natural selection

Answer 1

variation, heritability, competition and fitness

Question 2

continuous vs discrete variation

Answer 2

• discrete: coded for by 1/2 genes
• continuous: controlled by many genes. eg cepaea nemoralis shell pattern and colour

Question 3

true or false menedlian inheritance does not produce a change in gene frequency, what does this show about heritability

Answer 3

true
heritability cant be relied on alone to evolve

Question 4

what is fitness

Answer 4

• the measure of the reproductive success of an individual
• if individuals pass on 100% of their genes to the next gen, fitness = 1.0
• needs at least to offspring for this to occur

Question 5

moth species that went from white to black during industrial rev

Answer 5

biston betularia - peppered moth

Question 5

relationship between colour and environment for mushrooms

Answer 5

• link between temp and colour and latitude and colour
• darker colours absorb more heat

Question 6

example of stabalising selection

Answer 6

• bicyclus anynana butterfly
• eyespots provide defense against predators
• selection against eyespots that are too large or small

Question 6

how is fitness split into natural and sexual selection

Answer 6

• natural: survival, fecundity and fertility
• sexual: reproduction, number of mates

Question 6

types of natural selection

Answer 6

• directional: long term change in a trait towards an extreme of the pop, observable in evolutionary data
• stabalising: selection against extreme values
• disruptive: multiple optimal traits

Question 7

example of disruptive selection

Answer 7

• pyrenestres ostrinus - black bellied seedcraker
• small and big beak selected for dep on food source