Cambridge IGCSE Biology (BES) 0438 — 2012 May/June Paper 2 · Variant 3

This document consists of 17 printed pages and 3 blank pages. IB12 06_0438_23/RP © UCLES 2012 [Turn over *5916369772* For Examiner's Use 1 2 3 4 5 6 7 8 9 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education BIOLOGY (US) 0438/23 Paper 2 Core May/June 2012 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Center number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question.

2 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 1 Fig. 1.1 shows five types of bird that are unable to fly. A B C D E Fig 1.1

3 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use Use the key to identify each of the birds shown in Fig. 1.1. Write the name of each bird in the correct box in Table 1.1. Key name of bird 1 (a) Bird with webbed feet (webs of skin between toes) (b) Bird without webbed feet (no webs of skin between toes) 2 (a) Bird with tufts of feathers near the eyes (b) Bird with no tufts of feathers near the eyes 3 (a) Bird with crest on head (b) Bird without crest on head 4 (a) Bird with very long neck (b) Bird with short neck go to 2 go to 3 E. crestatus P. adeliae C. casuarius go to 4 S. camelus A. australis Table 1.1 bird name of bird A B C D E [5] [Total: 5]

4 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 2 (a) Fig. 2.1 shows a section through the heart. A B C D E F G H V Fig. 2.1 (i) Table 2.1 lists functions of parts of the heart and associated blood vessels. Complete the table by identifying which structure, A to H, carries out each of the following functions. Table 2.1 function letter vessel returning blood from the body chamber which pumps blood to the body vessel which carries blood to the lungs vessel which carries blood at the highest pressure [4] (ii) Describe the function of structure V. [2]

5 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use (b) A person’s pulse rate rises as they run a race. (i) Explain why the pulse rate rises during the race. [3] (ii) Describe how you could measure the pulse rate of a person. [2] [Total: 11]

6 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 3 (a) Fig. 3.1 shows variegated (green and white) leaves on a destarched plant. Part of one of the leaves was covered. leaf cover green area white area Fig. 3.1 (i) The plant was left in bright light for 24 hours and then the cover was removed from the leaf. The leaf was tested for the presence of starch. leaf with cover removed green area white area original position of cover L K M N Fig. 3.2 Suggest which areas of the leaf, as shown in Fig. 3.2, would have contained starch after 24 hours. Table 3.1 area contains starch key K …………………………...
= starch present L …………………………... x = starch absent M …………………………... N …………………………... Record your suggestions in Table 3.1. [2]

7 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use (ii) Give reasons for your suggestions for areas K and L. area K area L [4] (iii) Starch is formed from a simple carbohydrate. Name the process, carried out by plants, that produces this simple carbohydrate. [1] (iv) State which gas is released from the leaf when this simple carbohydrate is being produced. [1] (b) Magnesium ions are needed to form the green pigment in the leaf. (i) State where magnesium ions enter a plant. [1] (ii) Suggest how magnesium ions enter a plant. [2] [Total: 11]

8 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 4 Fig. 4.1 shows a section through the male reproductive system. B A Fig. 4.1 (a) (i) Name the structures labelled A and B. A B [2] (ii) On Fig 4.1 label with a line and the letter T where the hormone testosterone is produced. Put the line and letter on Fig. 4.1 [1] (iii) Name the stage in a male child’s development when the secondary sexual characteristics appear. [1] (iv) Sometimes athletes attempt to cheat by taking performance enhancing drugs such as testosterone. Suggest two ways in which taking testosterone may give them an unfair advantage in a competition. 1 2 [2]

9 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use (b) If a man damages his hip he might require an X-ray. Suggest why it is important to protect his testes from radiation, such as X-rays. [3] [Total: 9]

10 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 5 Tropical rainforest is one of the habitats with the greatest number of species on the Earth but it is being rapidly destroyed. (a) Table 5.1 shows data from six countries that have large areas of tropical rainforest. Table 5.1 country area of rainforest in 1990 / thousand ha area of rainforest in 2005 / thousand ha Brazil 520 027 477 695 Ecuador 13 817 10 853 Indonesia 116 567 88 497 Madagascar 13 692 12 855 Philippines 10 561 7 181 Venezuela 52 026 47 713 (i) Which country had the largest area of tropical rainforest in 2005? [1] (ii) Calculate the total area of rainforest lost in the Philippines between 1990 and 2005. answer = thousand ha [1] (iii) In the space below calculate the percentage of tropical rainforest lost in the Philippines between 1990 and 2005. Show your working. answer = % [2]

11 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use (b) One method of deforestation is to remove the large trees for timber and then burn the rest of the vegetation. Explain why deforestation is considered harmful to the environment. [4] [Total: 8]

12 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 6 A person’s blood glucose concentration should remain within narrow limits. (a) (i) Name the process that keeps conditions inside the body within narrow limits. [1] (ii) Name the main process that uses glucose from the blood. [1] (b) The graph, Fig. 6.1, shows the blood glucose concentration of a boy over 14 hours. 6 am 8 am 10 am 12 noon time of day 2 pm 4 pm 6 pm 8 pm meal 160 140 120 100 80 60 40 0 blood glucose / mg per 100 cm3 blood leaves school leaves school leaves school Fig. 6.1

13 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use The boy had a meal at about 7.45 am. (i) What was the boy’s blood glucose concentration before this meal? mg per 100 cm3 blood [1] (ii) What was the boy’s maximum blood glucose concentration after this meal? mg per 100 cm3 blood [1] (c) After the meal the boy’s pancreas secreted a hormone that helped to remove excess glucose from the blood and store it. (i) On Fig. 6.1 mark with a letter G when the pancreas started to secrete this hormone. [1] (ii) State the form in which glucose is stored in the body. [1] (iii) State one organ in the body where this storage occurs. [1] (d) On the way home from school, the boy was involved in a fight. (i) State what happened to the boy’s blood glucose concentration at the start of the fight. [1] (ii) During the fight the boy’s body produced another hormone. Name this hormone. [1] (iii) Describe three effects this hormone had on the boy’s body. 1 2 3 [3] [Total: 12]

14 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 7 Fig. 7.1 shows a bee visiting a flower. bee petal Fig. 7.1 (a) (i) State one advantage to the bee of its visit to this flower. [1] (ii) State one advantage to the flower of the visit by this bee. [1] (iii) Suggest two features of the flower that might have attracted the bee to the flower . 1 2 [2]

15 © UCLES 2012 0438/23/M/J/12 [Turn over For Examiner's Use (b) Fig. 7.2 shows the female part of a flower before fertilization. pollen grain style female gamete ovary attachment to rest of flower Fig. 7.2 Describe the events that must take place before a seed can develop. [3] (c) Explain why the seed that develops is likely to grow into a plant that is similar, but not identical, to its parent plants. [3] [Total: 10]

16 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 8 Small insect-eating birds are feeding on the caterpillars that are eating the leaves of a tree. A pair of sparrow hawks is hunting for small birds to feed their young. (a) Fig. 8.1 shows a pyramid of numbers for this food chain. organisms at each trophic level … … … … Fig. 8.1 (i) On Fig. 8.1, write the names of the organisms present at each trophic level. [1] (ii) In the space below draw a pyramid of biomass for this food chain. [2] (iii) State a reason for the different shapes of the two pyramids. [1] (b) (i) Name an organism in this food chain that is a herbivore. [1] (ii) Name an organism that is a carnivore. [1] (iii) Name a group of organisms that would be part of this food chain but which are not included in either pyramid. [1] [Total: 7]

17 © UCLES 2012 0438/23/M/J/12 For Examiner's Use 9 Fig. 9.1 shows two front views, S and T, of a human eye in two different light intensities. S T changes to Fig. 9.1 (a) (i) Suggest how the light intensity changes from S to T. [1] (ii) Explain how the changes in the eye, shown in Fig. 9.1, were brought about. [3] (b) The changes in the appearance of the pupil are known as the “pupil reflex”. (i) Describe the characteristics of a reflex action. [2] (ii) Suggest how the pupil reflex protects the eye. [1] [Total: 7]

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20 Copyright Acknowledgements: Question 1 Photograph Question 1 Photograph Question 1 Photographs Question 5a © University of Edinburgh; http://www.nhc.ed.ac.uk/index.php?page=493.457.461. © http://www.communigate.co.uk/ne/penguins/page7.phtml. © Austin & Singer; Birds of the World; The Reprint Society; 1962. © ADAPTED: http://rainforests.mongabay.com/deforestation. Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2012 0438/23/M/J/12 BLANK PAGE

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the May/June 2012 question paper for the guidance of teachers 0438 BIOLOGY (US) 0438/23 Paper 2 (Core Theory), maximum raw mark 80 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes must be read in conjunction with the question papers and the report on the examination. • Cambridge will not enter into discussions or correspondence in connection with these mark schemes. Cambridge is publishing the mark schemes for the May/June 2012 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

Page 2 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 General notes Do not exceed the section sub-totals or question maxima. Symbols used in mark scheme and guidance notes. / separates alternatives for a marking point ; separates points for the award of a mark MP mark point – used in guidance notes when referring to numbered marking points ORA or reverse argument / reasoning OWTTE or words to that effect A accept – as a correct response R reject – this is marked with a cross and any following correct statements do not gain any marks I ignore / irrelevant / inadequate – this response gains no mark, but any following correct answers can gain marks. ( ) the word / phrase in brackets is not required to gain marks but sets the context of the response for credit. e.g. (waxy) cuticle. Waxy not needed but if it was described as a cellulose cuticle then no mark is awarded. mitosis underlined words – this word only

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 1 (a) A – A. australis; B – E. crestatus; C – C. casuarius; D – S. camelus; E – P. adeliae; [5] [Total: 5] 2 (a) (i) C; (vessel returning blood from the body) H; (chamber which pumps blood to the body) D; (vessel which carries blood to the lungs) E; (vessel carrying blood at the highest pressure) [4] (ii) 1 prevents backflow of blood; 2 from artery / aorta / E / to ventricle / H; [2] (b) (i) 1 exercise / running needs more energy; 2 body / muscles / cells respire more rapidly; 3 (body / muscles / cells) need more oxygen / glucose; 4 (heart) pumps blood faster (to supply this); 5 removes carbon dioxide / heat; Any three – 1 mark each [3] (ii) 1 identified suitable position / where artery crosses a bone / OWTTE; 2 press on spot with finger; 3 (count) number of beats per minute Any two – 1 mark each [2] [Total: 11] A – when ventricle relaxes Candidate only needs refer to “more” (or equivalent term) once. 1 A – carotid or radial pulse, wrist, neck 2 A – ref to digital pulse meter

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 3 (a) (i) area contains starch K
L  M
N
area L correct; areas K, M and N correct; [2] (ii) (area K) 1 has no chlorophyll / chloroplasts; 2 cannot photosynthesise / form starch; (area L) 3 has both light and chlorophyll / chloroplasts; 4 can photosynthesise / form starch; [4] (iii) photosynthesis; [1] (iv) oxygen [1] (b) (i) root hair (cell); [1] (ii) 1 from soil water / in solution in soil water; 2 by diffusion; 3 down concentration gradient; any two – 1 mark each [max 2] [Total: 11]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 4 (a) (i) A – prostate (gland); B – urethra; [2] (ii) line to testis labelled T; [1] (iii) puberty; [1] (iv) 1 causes increased growth of limb bones; 2 causes increased muscle development / growth; 3 increases lung capacity; any two – 1 mark each [max 2] (b) 1 can kill sperm / cause sterility; 2 testes contain dividing cells; 3 undergoing meiosis / gamete formation; 4 X-ray / radiation may cause damage to nucleus; 5 that may result in defects / mutations; 6 can be passed on to offspring; any three – 1 mark each [max 3] [Total: 9] 1 A – cause cancer of the testes 4 A – chromosomes, genes, DNA

Page 6 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 5 (a) (i) Brazil; [1] (ii) (10561 – 7181) 3380 (ha); [1] (iii) loss = 10561 100 7181) (10561 × − A – ecf of value from (a)(ii) = 32(.00) (%);; [2] (b) 1 removes habitats (for wildlife / animals); 2 disrupts food chains; 3 leads to loss of species / reduces biodiversity; 4 exposed soil dries out / desertification may occur; 5 easily eroded; 6 less transpiration / evaporation; 7 less cloud formation / rainfall; 8 (burning) increases carbon dioxide content of the air; 9 less photosynthesis so more carbon dioxide in air; any four – 1 mark each [max 4] [Total: 8] Correct answer but no working shown = 2 marks 5 A – refs to landslips

Page 7 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 6 (a) (i) homeostasis; [1] (ii) respiration; [1] (b) (i) 72 (mg per 100 cm3); [1] (ii) 150 (mg per 100 cm3); [1] (c) (i) letter G on rising line (8am – 10am) before turndown; [1] (ii) (glucose converted to) glycogen; (iii) (stored in cells of) liver / muscles; [2] A – named muscle (d) (i) dropped / decreased / goes from 72 to 55 mg per 100 cm3 of blood; [1] (ii) adrenaline; [1] (iii) 1 increase in metabolic activity / OWTTE; 2 increase in heart rate; 3 glycogen converted to glucose; 4 increase blood glucose level; 5 increase rate of respiration; any three – 1 mark each [3] [Total: 12] 1 A – chemical reactions / processes occur more rapidly 2 A – increase in stroke volume

Page 8 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 7 (a) (i) collects food / nectar / pollen; [1] (ii) bring about pollination; [1] (iii) 1 smell / scent / odour; 2 colour of petals; 3 shape / size of petals; any two – 1 mark each [max 2] (b) 1 pollen grain produces pollen tube; 2 male gamete formed inside pollen grain; 3 pollen tube grows down through stigma and style; 4 enters ovule; 5 male gamete passes along pollen tube; 6 fuses with female gamete (in ovule); any three – 1 mark each [max 3] (c) 1 (new plant) genotype different to original parents; 2 it has genes from female parent / gamete; 3 it has genes from male parent / gamete; 4 phenotype may show features from both parents; 5 also affected by environmental factors; any three – 1 mark each [max 3] [Total: 10] A – description of pollination

Page 9 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 8 (a) (i) (sparrow) hawk insect-eating bird caterpillar tree layers in Fig. 8.1 labelled from top to bottom [1] (ii) 4 blocks to pyramid widening from top to bottom / triangle shaped pyramid widest at base; labelled as per (a)(i) / other appropriate labels; [2] (iii) only 1 tree but has mass larger than any other layer in pyramid / OWTTE; [1] (b) (i) caterpillar; [1] (ii) insect-eating birds / (sparrow) hawk; [1] (iii) decomposers / bacteria / fungi; [1] [Total: 7] A – small birds A – insect A – small birds / bird

Page 10 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – May/June 2012 0438 23 © University of Cambridge International Examinations 2012 9 (a) (i) gets brighter / increases (at T); [1] (ii) 1 increase in light intensity detected by retina; 2 impulses to iris (via brain) 3 (iris) circular muscles contract; 4 (iris) radial muscles relax; 5 making pupil smaller; any three – 1 mark each [max 3] (b) (i) 1 rapid / immediate; 2 specific response to specific stimulus; 3 automatic / no conscious thought; any two – 1 mark each [max 2] (ii) protects retina / light sensitive cells from damage (by too much light); [1] [Total: 7]