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Investigating diversityAQA A-Level Biology: Flashcards

What these 13 flashcards ask

  • What is genetic diversity?
  • List four ways of investigating genetic diversity.
  • What does it suggest if two species have few differences in the sequence of a protein?
  • Why do more differences in sequence suggest a more distant relationship?
  • Why can DNA differences exist without protein differences?
  • What else can DNA comparison show that proteins cannot?
  • Why are observable characteristics a limited measure of genetic diversity?
  • How has gene technology changed investigation of genetic diversity?
  • Why use random samples when investigating variation?
  • What does standard deviation measure?
  • What does a large standard deviation show?
  • What does an overlap in mean ± standard deviation for two samples suggest?
  • Are you required to calculate standard deviations in written papers?

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
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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).