Biology · 2013 · November · Paper 3 · HL · Question paper

25 pages N13/4/BIOLO/HP3/ENG/TZ0/XX Thursday 14 November 2013 (morning) BIOLOGY HIGHER LEVEL PAPER 3 INSTRUCTIONS TO CANDIDATES • Write your session number in the boxes above. • Do not open this examination paper until instructed to do so. • Answer all of the questions from two of the Options. • Write your answers in the boxes provided. • A calculator is required for this paper. • The maximum mark for this examination paper is [40 marks]. Option Questions Option D — Evolution 1 – 3 Option E — Neurobiology and behaviour 4 – 6 Option F — Microbes and biotechnology 7 – 9 Option G — Ecology and conservation 10 – 12 Option H — Further human physiology 13 – 15 1 hour 15 minutes © International Baccalaureate Organization 2013 Examination code 8 8 1 3 – 6 0 0 3 [Personal identifier removed] 28EP01 8813600 3 – 2 – N13/4/BIOLO/HP3/ENG/TZ0/XX 28EP02 Option D — Evolution 1. Analysis of the genome of primates reveals many DNA segments that have been duplicated. It is possible to deduce the stage in evolution at which segmental duplications (SDs) occurred by comparing human and other primate genomes. Human-specific SDs occurred after humans and chimpanzees diverged. Human-chimpanzee shared SDs occurred after the common human-chimpanzee ancestor diverged from gorillas and so on. It is possible to estimate the rates at which SDs occurred during evolution using knowledge of when the primates changed. In the chart the bars indicate numbers of shared SDs and the line shows estimates of the rate of SDs per millions of years (Myr). Number of SDs 300 250 200 150 100 50 0 60 50 40 30 20 10 0 Rate of SDs per Myr Human- Human- Human- Human- Human- specific chimpanzee chimpanzee- chimpanzee- chimpanzee- SDs shared SDs gorilla gorilla- gorilla- shared SDs orangutan orangutan- shared SDs macaque shared SDs Key: number of SDs SDs per Myr [Source: Reprinted by permission from Macmillan Publishers Ltd: Tomas Marques-Bonet, Jeffrey M. Kidd, Mario Ventura, Tina A. Graves and Ze Cheng et al. (2009) ‘A burst of segmental duplications in the genome of the African great ape ancestor.’ Nature, 457, pp. 877–881.] (a) (i) State the number of SDs that can be found in humans but not in other