AQA A LEVEL BIOLOGY Paper 3 MS 2021

A-level BIOLOGY Paper 3 Monday 15 June 2020 Morning Time allowed: 2 hours Materials For this paper you must have: • a ruler with millimetre measurements • a scientific calculator. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions in Section A. • Answer one question from Section B. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Show all your working. • Do all rough work in this book. Cross through any work you do not want to be marked. Information • The marks for the questions are shown in brackets. • The maximum mark for this paper is 78. *JUNDo0wnl1oad* For Examiner’s Use Question Mark 1 2 3 4 5 6 7 TOTAL Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides *02* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 1 Section A Answer all questions in this section. You are advised to spend no more than 1 hour and 15 minutes on this section. Do not write outside the box 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 choosing a mate. They used laboratory-bred female guppies with large brains and with small brains. They set up a fish tank as shown in Figure 1. Figure 1 They observed each female for 10 minutes and recorded which male they were attracted towards. They repeated this with 45 large-brained females and 45 small-brained females. . Suggest three possible limitations of this investigation. [3 marks] 1 2 3 0 1 0 1 Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S S - The Marketplace for Revision Notes & Study Guides - The Marketplace for Revision Notes & Study Guides 3 *03* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 2 3 9 Guppies with large brains are better at identifying predators. The scientists found that only female guppies with large brains were attracted to male guppies bright in colour. Do not write outside the box . Suggest and explain the advantage of this behaviour to the population of guppies. [3 marks] . Describe how the behaviour of female guppies could result in sympatric speciation. [3 marks] Turn over ► 0 1 0 1 Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S S - The Marketplace for Revision Notes & Study Guides - The Marketplace for Revision Notes & Study Guides 4 *04* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 1 In northern India, there is a conflict of interests between farmers of livestock (eg cows) and people trying to conserve ibex (a type of wild goat). When livestock are given extra food, their populations can grow too large and compete with ibex. Do not write outside the box . Name the type of competition between livestock and ibex. [1 mark] Livestock will outcompete ibex if they: • are in the same habitat • eat a similar diet. Scientists investigated this conflict of interests. Table 1 summarises some of the scientists’ finding