Genetic Variation

Question 1

What is directional selection?

Answer 1

• often due to environmental change e.g. weather or food.
• an advantage is that an allele may increase in frequency even if its recessive.
  -e.g. finch beak size decreases in wet weather as available seeds decrease in size

Question 2

What is stabilising selection?

Answer 2

• it works mostly on polygenic traits
• e.g. birth weights of babies or the number of eggs laid by birds.

Question 3

How do animals impress members of the opposite sex?

Answer 3

Dancing, singing, noises, colours

Question 4

Lions

Answer 4

Bigger the mane the more important

Question 5

What’s the importance of courtship?

Answer 5

• enables potential mates to recognise their own species
• avoids aggression between individuals
• enables potential mates to synchronise their breeding behaviour

Question 6

When does courtship usually happen?

Answer 6

Spring, due to increased day length.