West Spring 2018 Bio Prelim P2 QP

West Spring Secondary School PRELIMINARY EXAMINATION 2018 Biology 6093/02 SECONDARY 4 EXPRESS Name ( ) Date 13 Sep 2018 Class Duration 1 h 45 min READ THESE INSTRUCTIONS FIRST Write your name, class and register number on the cover page. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A (50 Marks) Answer allquestions. Write your answers in the spaces provided on the Question Paper. Show allrelevant working. Section B (30 Marks) Answer all the questions. Write your answers in the spaces provided on the Question Paper. Electronic calculators may be used Information for Candidates You are advised to spend no longer than one hour on Section A and no longer than 45 minutes on Section B. The number of marks is given in [ ] at the end of each question or part question. FOR EXAMINER’S USE Section A /50 Section B /30 Total /80 This document consists of 18printed pages including the cover page. Setter(s) Mdm Ho Soo Yin [Turn over] www.KiasuExamPaper.com 479

2 Section A Answer allquestions. Write your answer in the spaces provided. 1 Fig. 1.1 shows a food web in an ecosystem. h a w k s s n a k e s b i r d s b e e s g r a s s h o p p e r s c a t e r p i l l a r s a f l o w e r i n g t r e e Fig. 1.1 (a) Draw a pyramid of numbers for a food chain involving caterpillars. [ 1 ] (b) It is known that consumers at the highest trophic level receive the highest amount of insecticides. Based on the pyramid of numbers you have drawn in (a), explain why this is so. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ..........................................................................................................................................................[3] www.KiasuExamPaper.com 480

3 (c) Explain the observations of the following populations when snakes are removed from this food web. (i)The grasshopper population increases initially but decreases afterwards. ....................................................................................................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [ 3 ] (ii)The caterpillar population was constant for a while but decreases afterwards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [ 2 ] [ T o t a l : 9 ] 2 A surgeon carried out a biopsy on a child who was not gaining t he weight expected for his age. A small sample of tissue was removed from inside the child’s small intestine. Fig. 2.1 shows the appearance of the villi in a normal healthy child and that of the child patient’s small intestine of the same age. Both diagrams are to the same scale. Fig. 2.1 healthy child child patient www.KiasuExamPaper.com 481

4 (a) With reference to Fig. 2.1, state one difference between the villi of the healthy child and that of the patient. .......................................................................................................................................................... ..........................................................................................................................................................[1] (b) Describe and explain three otherfeatures of a healthy small intestine that help to maximise the absorption of digested food. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ..........