Investigating diversityAQA A-Level Biology: Mind map

Exam questions on Investigating diversity

1. Scientists compared the amino acid sequence of the same protein, cytochrome c, from four species and counted the number of differences from the human sequence. The chimpanzee sequence had 0 differences, the rhesus monkey sequence had 1, the horse sequence had 12 and the tuna sequence had 21.
   Explain why the human cytochrome c sequence has fewer differences from that of the rhesus monkey than from that of the tuna.2 marks
2. Two individuals of the same beetle species were found to differ by one base in the DNA sequence of the gene coding for an enzyme. When the amino acid sequences of the enzyme in the two beetles were compared, they were identical.
   Suggest why comparing the base sequences of DNA gives a more complete measure of genetic diversity than comparing amino acid sequences.2 marks
3. A biologist measured the wing length of 50 randomly chosen moths from each of two populations. The mean wing length of population A was 24.2 mm with a standard deviation of 1.1 mm. The mean wing length of population B was 25.0 mm with a standard deviation of 3.2 mm.
   Explain what the standard deviations show about the wing lengths of the two populations.3 marks