
	Trending ▼ ICSE CBSE 10th ISC CBSE 12th CTET GATE UGC NET Vestibulares ResFinder

GCE JAN 2011 : (AS 2) Organisms and Biodiversity - Revised

21 pages, 42 questions, 0 questions with responses, 0 total responses,

	gce	+Fave Message
	Profile Timeline Uploads Q & A

Home > gce >

Instantly get Model Answers to questions on this ResPaper. Try now!
NEW ResPaper Exclusive!

Formatting page ...

Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2011 Biology assessing Organisms and Biodiversity AB121 Assessment Unit AS 2 [AB121] TUESDAY 18 JANUARY, AFTERNOON TIME 1 hour 30 minutes. INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces provided at the top of this page. Write your answers in the spaces provided in this question paper. Answer all nine questions. You are provided with Photograph 2.4 for use with Question 4 in this paper. Do not write your answers on this photograph. INFORMATION FOR CANDIDATES 111528 The total mark for this paper is 75. Section A carries 60 marks. Section B carries 15 marks. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. You are reminded of the need for good English and clear presentation in your answers. Use accurate scientific terminology in all answers. You should spend approximately 20 minutes on Section B. You are expected to answer Section B in continuous prose. Quality of written communication will be assessed in Section B, and awarded a maximum of 2 marks. 6887 For Examiner s use only Question Number 1 2 3 4 5 6 7 8 9 Total Marks Marks Section A Examiner Only Marks 1 Remark Fungi are described as lysotrophs and feed by extracellular digestion. (a) Explain why fungi are described as lysotrophs. _____________________________________________________________ ___________________________________________________________ [1] (b) Describe the process of extracellular digestion. _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [2] 6887 2 [Turn over 2 An investigation was designed to determine the effect of light intensity on gas exchange by pondweed. The experiment setup is shown in the diagram below. Examiner Only Marks Remark In A, the lamp was placed close to a test tube containing pondweed immersed in an indicator solution. In B, the lamp was placed further away. In each case, the indicator was orange-red initially. After 1 hour, the colour was observed and recorded. The experimental setup and results are shown below. indicator solution turns purple A beaker of water light source indicator solution remains orange-red B light source (a) Name the indicator solution used and the gas which caused the change in A. Indicator solution _____________________________________________ Gas ___________________________________________ [1] (b) Suggest a reason for the test tube containing the pondweed being placed in a beaker of water. _____________________________________________________________ ___________________________________________________________ [1] (c) Explain why the indicator solution remained orange-red in B. _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [2] 6887 3 [Turn over 3 Contraction of heart muscle causes an increase in pressure within the heart chambers. Examiner Only Marks Remark (a) State the term for the phase of the cardiac cycle during which heart muscle is contracted. [1] (b) The muscle surrounding the heart chambers is of different thicknesses. The graph below shows the maximum pressure reached in each of the heart chambers during contraction. left ventricle right ventricle left atrium right atrium 0 5 10 15 20 Pressure/kPa Using your understanding of the structure of the heart chambers, explain why the maximum pressure in both atria is the same, whereas the pressure in the left ventricle is much greater than the pressure in the right ventricle. _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [3] 6887 4 [Turn over 4 Photograph 2.4 is a photomicrograph of a transverse section through a leaf of heather (genus Erica). Heather is a xerophyte. Examiner Only Marks Remark (a) In the space below, draw a block diagram to show the tissue layers in the leaf as shown in the photograph. Label the tissue layers. [5] (b) Explain how each of the following xerophytic features in the heather leaf further limits water loss. The thick cuticle ______________________________________________ _____________________________________________________________ Hairs on the surface ___________________________________________ ___________________________________________________________ [2] 6887 5 [Turn over 5 In an investigation of hedgerow biodiversity, two hedges were systematically sampled (i.e. sampled at regular intervals) along their length. The two hedges differed in the degree to which they were managed and one had become gappy through lack of management. The hedges were arbitrarily called A and B. Examiner Only Marks Remark (a) Describe another location where the use of systematic sampling along a transect is appropriate. Explain why this technique is most suitable in this situation. _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [2] The table below shows the results of sampling the plant species within hedge A. Number of each species (ni) ni (ni 1) Bramble, Rubus spp. 26 650 Ivy, Hedera helix 13 156 Stinging nettle, Urtica dioica 8 X _____________ Cleavers, Galium aparine 6 30 Cow parsley, Anthriscus sylvestris 5 20 Gorse, Ulex europaeus 4 12 Herb Robert, Geranium robertianum 3 6 Hawthorn, Crataegus monogyna 4 12 Hazel, Corylus avellana 2 2 Sycamore, Acer pseudoplatanus 2 2 Wild cherry, Prunus avium 2 2 Species found Total N = 75 Sni (ni 1) ______ (b) (i) Complete the table by calculating the missing values X and Sni (ni 1). 6887 6 [2] [Turn over (ii) Using values from the table and the formula below calculate a Simpson s index value for hedge A. (Show your calculations.) The formula for the Simpson s index is D = Examiner Only Marks Remark n i (n i 1 ) N (N 1) [2] (iii) Hedge B had a Simpson s index of 0.4. State which hedge was managed to encourage biodiversity. Explain your choice. Hedge ___________________________________________________ _________________________________________________________ _______________________________________________________ [2] (c) Describe two strategies which are recommended to maintain a good hedge. 1. ___________________________________________________________ _____________________________________________________________ 2. ___________________________________________________________ ___________________________________________________________ [2] 6887 7 [Turn over 6 An investigation was undertaken to determine the relationship between stomatal density and the rate of transpirational water loss in daffodil leaves. Examiner Only Marks Remark The stomata of daffodil leaves are found on both surfaces of the leaf. (a) A student took five counts of stomata in areas 2 mm 2 mm (4 mm2) on both surfaces. The mean number of stomata per 4 mm2 was then calculated and, for the upper epidermis, this was converted to a count per cm2. The results are shown in the table below. Number of stomata Upper epidermis 136 Mean count/4 mm 2 Mean count/cm 2 67 146 81 132 90 154 Replicated counts/ 4 mm 2 Lower epidermis 58 142 74 3550 (i) Complete the table by entering a mean value for the number of [1] stomata per cm2 in the shaded cell. (ii) Assess the variation shown within the replicates and comment on reliability of the measurements. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] 6887 8 [Turn over (b) An estimate was made of the amount of transpiration from both surfaces of a daffodil leaf by sticking small pieces of dry cobalt chloride paper on the upper and lower epidermis. The cobalt chloride paper changes from blue to pink as it absorbs water. The graph below shows the colour changes over a period of 60 minutes. Examiner Only Marks Remark upper epidermis lower epidermis pink Colour of cobalt chloride paper pale pink very pale pink white very pale blue pale blue blue 0 10 20 30 40 50 60 Time/min (i) Using the information in the graph and the table opposite, explain the colour changes shown. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] (ii) Covering part of the leaf with the cobalt chloride paper may reduce the transpiration in that part. Suggest one reason for this. _________________________________________________________ _______________________________________________________ [1] 6887 9 [Turn over (c) Explain how water loss from the leaf provides a means for water transport in the whole plant. Examiner Only Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [2] 6887 10 [Turn over 7 The diagram below represents a transverse section through a blood vessel. Examiner Only Marks Remark (a) Select two pieces of evidence visible in the diagram which suggest that this is an artery. 1. ___________________________________________________________ 2. _________________________________________________________ [2] (b) The wall of an artery contains smooth muscle tissue. Explain the role of the smooth muscle tissue in the functioning of an artery. _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [2] (c) Distinguish between the terms atheroma and atherosclerosis and explain how they may lead to a coronary thrombosis (heart attack). _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [5] 6887 11 [Turn over 8 The distribution of bird populations is greatly influenced by changes in farming practice. A recent introduction involves the planting of tree species such as poplar or willow. These fast growing trees are harvested after a number of years to produce wood pellets for use as a fuel. This practice is called Short Rotation Coppicing (SRC). Examiner Only Marks Remark After several years, the trees form a dense plantation on land that was previously used for growing crops (arable land) or as grassland. The effects of changing land use to SRC was investigated for three bird species: the lapwing (Vanellus vanellus), the snipe (Gallinago gallinago) and the woodcock (Scolopax rusticola). (a) State the genus name of the woodcock. ___________________________________________________________ [1] (b) In the investigation of changing land use on the bird species, biologists visited farms to take counts of each species in four areas: short rotation coppices (SRC) on land previously used as arable land neighbouring area maintained as arable land short rotation coppices (SRC) on land previously used as grassland neighbouring area maintained as grassland Mean number of birds recorded per visit Lapwing Snipe Woodcock SRC on arable Arable SRC on grass Grass (i) Explain why the counts were made on neighbouring arable fields and on neighbouring grassland. _________________________________________________________ _______________________________________________________ [1] 6887 12 [Turn over (ii) Using the information in the graph, state Examiner Only Marks Remark which of the three bird species seems to prefer the habitat of the grassland and arable land rather than the plantation habitat produced by SRC. _____________________________________________________ which of the two areas of SRC (previously grassland or arable) causes benefits in terms of biodiversity. ___________________________________________________ [2] (iii) Suggest one reason why SRC can cause a change in the numbers of these bird species. _________________________________________________________ _______________________________________________________ [1] (c) Biologists also investigated plant species that were associated with the floor of the SRC and the changes which occurred over a four year period. Plants were sampled and their numbers recorded at the edge of the SRC and in the middle of the SRC. (i) Describe an appropriate sampling procedure, which ensures that results are representative of the plant species present in the two regions. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] 6887 13 [Turn over The results for the number of different plant species found, in the years following the planting of trees, are shown in the graph below. Examiner Only Marks Remark Number of plant species Edge of SRC Middle of SRC 1 2 3 4 Age of SRC growth (years) (ii) One trend evident in the graph suggests that more plant species are found at the edge of the SRC. Suggest how two possible ecological factors may account for this difference. 1. _______________________________________________________ _________________________________________________________ 2. _______________________________________________________ _______________________________________________________ [2] (iii) Describe one other trend evident in the graph and suggest a possible explanation for it. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] 6887 14 [Turn over (d) In a separate study, biologists looked at the number of insect species living in the canopy of the trees planted in the SRC. Several SRCs were sampled in the first year after planting (Recent SRC) and again after four years (Established SRC). As in the plant survey, the biologists sampled at the edge and in the middle of the SRC. The total numbers of insects found are shown in the graph below. Examiner Only Marks Remark Total numberr of insects Edge of SRC Middle of SRC Recent SRC Established SRC (i) Describe two conclusions which may be made on the basis of these results. 1. _______________________________________________________ _________________________________________________________ 2. _______________________________________________________ _______________________________________________________ [2] (ii) Suggest one way in which insects may be of benefit to the biodiversity of an SRC. _________________________________________________________ _______________________________________________________ [1] 6887 15 [Turn over Section B Examiner Only Marks 9 Quality of written communication is awarded a maximum of 2 marks in [2] this section. (a) Give an account of the structure of haemoglobin and its role in absorbing oxygen in the lungs. Remark [5] (b) Explain how oxygen is supplied to strenuously exercising muscle. [8] (a) Give an account of the structure of haemoglobin and its role in absorbing oxygen in the lungs. _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ 6887 1 6 [Turn over _____________________________________________________________ Examiner Only Marks _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ (b) Explain how oxygen is supplied to strenuously exercising muscle. _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ Remark _____________________________________________________________ 6887 1 7 [Turn over Examiner Only _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ 6887 1 8 Marks Remark [Turn over THIS IS THE END OF THE QUESTION PAPER 6887 19 [Turn over Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 111528 6887 20 [Turn over GCE Biology Advanced Subsidiary (AS) Assessment Unit AS2 assessing Organisms and Biodiversity January 2011 Photograph 2.4 Dr Keith Wheeler/Science Photo Library 6887.02 111601

Formatting page ...

Additional Info : Gce Biology January 2011 Assessment Unit AS 2 Module 2: Organisms and Biodiversity - Revised
Tags : General Certificate of Education, A Level and AS Level, uk, council for the curriculum examinations and assessment, gce exam papers, gce a level and as level exam papers , gce past questions and answer, gce past question papers, ccea gce past papers, gce ccea past papers

gce chat

Horizontal lines at:
Guest Horizontal lines at:
AutoRM Data:
Box geometries: