Photo AI
Guppies are small fish - AQA - A-Level Biology - Question 1 - 2020 - Paper 3
Question 1
Guppies are small fish. Female guppies are dull in colour. Male guppies can be bright or dull in colour. Scientists investigated the effect of female brain size on ... show full transcript
Worked Solution & Example Answer:Guppies are small fish - AQA - A-Level Biology - Question 1 - 2020 - Paper 3
Step 1
Suggest three possible limitations of this investigation.
Answer
- Laboratory-raised female guppies might not react/behave or choose in the same way as wild guppies.
- The transparent barrier might not allow for normal (courtship) behaviour or interaction between the guppies.
- A duration of 10 minutes might not be long enough for females to make a final choice.
Step 2
Suggest and explain the advantage of this behaviour to the population of guppies.
Answer
- Females with large brains will mate with males bright in colour.
- Their offspring would be more likely to be bright in colour.
- Brightly coloured male offspring could attract larger-brained females, increasing their chances of survival and reproduction.
- The population will have offspring that are better at identifying and avoiding predators.
Step 3
Describe how the behaviour of female guppies could result in sympatric speciation.
Answer
- The behaviour of female guppies could lead to reproductive isolation since not all males will be chosen as mates.
- This could result in gene pools becoming separate, leading to changes in allele frequencies.
- Over time, if unable to breed with one another, there would be a chance for incompatible gene combinations, which could hinder or prevent fertility, ultimately contributing to speciation.