2024 JPJC Prelim Biology P3 (A)

9744 / 03 [Turn over NAME : CLASS : JURONG PIONEER JUNIOR COLLEGE JC2 Preliminary Examination 2024 BIOLOGY Higher 2 9744/03 11 September 2024 Paper 3 Long Structured and Free-response Questions 2 hours Additional Materials: Answer Booklet READ THESE INSTRUCTIONS FIRST Write your class and name in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one question on the separate Answer Booklet provided. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 2 3 Section B Total This document consists of 19 printed pages and 1 blank page.

2 JPJC/JC2 H2 Biology/Prelim/2024 Section A Answer all questions in this section. 1 Mammoths are extinct mammals related to elephants. About three million years ago, the ancestors of mammoths migrated from Africa into Europe and Asia. There, about 1.7 million years ago, the steppe mammoth evolved and became adapted to the cooler conditions. Then, about 700 000 years ago, as the climate changed and the Arctic became much colder, the woolly mammoth evolved. Characterised by its long, curved tusks, woolly mammoths showed several obvious adaptations to reduce heat loss, including thick fur, small ears and small tails. Fig. 1.1 shows a drawing of a woolly mammoth. Fig. 1.1 (a) (i) Outline the sources of genetic variation which drives microevolution in a population. ................................................................................................................... [2] 1. Gene mutations / chromosomal aberrations – ref. to changes to DNA sequences / chromosomal structure / number ; 2. 1 relevant stage in meiosis ; a) Crossing over between non-sister chromatids of homologous chromosomes during prophase I in meiosis I to give new combination of alleles in gametes b) Independent assortment of chromosomes in meiosis leads to new combination of alleles in the gametes formed c) Independent assortment and segregation of homologous chromosomes during metaphase I and anaphase I new combination of alleles in the gametes formed d) Independent assortment and segregation of recombinant chromatids during metaphase II and anaphase II leads to new combination of alleles in the gametes formed 3. Random fusion of gametes during fertilisation ; 4. ref to gene flow - transfer of alleles from one population to another due to migration of fertile individuals ;

3 JPJC/JC2 H2 Biology/Prelim/2024 [Turn over 5. Ge