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GCE JUN 2009 : (AS 2) Organisms and Biodiversity - Revised

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Sp ec Ne ifi w ca tio n 1 2 Centre Number 3 71 4 5 Candidate Number 6 ADVANCED SUbSIDIARy (AS) General Certificate of Education 2009 7 8 9 biology 11 Assessment Unit AS 2 12 assessing 13 Module 2: Organisms and Biodiversity 14 AB121 10 [Ab121] 15 FRIDAy 12 JUNE, AFTERNOON 16 17 18 19 20 TIME 1 hour 30 minutes INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces 21 provided at the top of this page. 22 Write your answers in the spaces provided in this question paper. Answer all eight questions. 23 You are provided with Photograph 2.3 for use with Question 3 in this 24 paper. Do not write your answers on this photograph. 25 26 INFORMATION FOR CANDIDATES 27 The total mark for this paper is 75. Section A carries 60 marks. Section B carries 15 marks. 28 Figures in brackets printed down the right-hand side of pages indicate the 29 marks awarded to each question or part question. You are reminded of the need for good English and clear presentation in 30 your answers. 31 Use accurate scientific terminology in all answers. You should spend approximately 20 minutes on Section B. 32 You are expected to answer Section B in continuous prose. Quality of written communication will be assessed in Section b, and 33 awarded a maximum of 2 marks. 34 4979 35 For Examiner s use only Question Marks Number 1 2 3 4 5 6 7 8 Total Marks Section A Examiner Only Marks 1 Remark Identify the word or phrase that is described by each of the following statements. Cells which form the walls of the alveoli and reduce the diffusion path for oxygen in the lungs. ______________________________________________________________________ Veins which carry oxygenated blood. ______________________________________________________________________ The effect whereby an increase in carbon dioxide causes a further release of oxygen from oxyhaemoglobin. ______________________________________________________________________ A pigment with a high affinity for oxygen found within red muscle. ___________________________________________________________________ [4] 4979 2 [Turn over 2 The distribution of two species of marine mollusc, Littorina littorea (the edible periwinkle) and Littorina saxatilis (the rough periwinkle), was investigated on a rocky shore. A belt transect from lower shore to upper shore indicated that L. littorea (the edible periwinkle) was found on the lower part of the shore and L. saxatilis (the rough periwinkle) was limited to the upper shore. Examiner Only Marks Remark Both species of periwinkle graze on algae which are abundant on the rocks. Also, they have a heavy shell (with a cover over the opening) to protect them from desiccation and mechanical damage. However, they differ in a number of ways. L. littorea (the edible periwinkle) produces fertile eggs which are released into the water and the larvae swim among the plankton. It has gills and can breathe for only a relatively short period out of water. L. saxatilis (the rough periwinkle) retains the fertilised eggs inside the body where they hatch so that there is no planktonic existence. The gills are modified to absorb air and it can survive for up to a month out of water. It has a high temperature tolerance and, in extremes of desiccation and temperature, it cements itself to a rock. (a) The lower shore area was covered by seawater for most of the day while the sea only reached the upper shore at high tide (twice a day). Explain how the adaptations of the L. saxatilis (the rough periwinkle) equip this periwinkle for life on the upper part of the shore. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ____________________________________________________________ [3] (b) Suggest an explanation why L. littorea (the edible periwinkle) outcompetes L. saxatilis (the rough periwinkle) on the lower shore. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ____________________________________________________________ [1] 4979 3 [Turn over 3 Photograph 2.3 is a photomicrograph of a transverse section through a leaf of the tobacco plant (Nicotiana tabacum). The tobacco leaf has some xerophytic adaptations. Examiner Only Marks Remark In the space below, draw a block diagram to show the tissue layers in the leaf as shown in the photograph. Annotate the drawing to identify two xerophytic features and, in each case, explain how the feature acts as an adaptation. Examiner Only Marks Remark [9] 4979 4 [Turn over BLANK PAGE (Questions continue overleaf) 4979 5 [Turn over 4 There are approximately 20 different species of free-living flatworm in Ireland. One such species is Dendrocoelum lacteum. Examiner Only Marks Remark (a) Define the term species . _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________ [2] (b) The diagrams below show two views of Dendrocoelum lacteum. Top view Side view Digestive system The flatworm lacks a blood system. Explain how it is adapted for the distribution of food and oxygen throughout its body. (i) Distribution of food ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ________________________________________________________ [2] (ii) Distribution of oxygen ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ________________________________________________________ [2] 4979 6 [Turn over Two species of flatworm, the New Zealand flatworm (Artioposthia triangulata) and the Australian flatworm (Australoplana sanguinea var. alba), have been introduced into Ireland. Both species predate earthworms. Examiner Only Marks Remark (c) These alien species are considered a threat to the biodiversity in the areas that they inhabit. Explain why. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________ [2] 4979 7 [Turn over 5 (a) The table below includes descriptions of three types of white blood cell. Complete the table by identifying each cell type and give a brief description of the function of each. Description Identi cation Examiner Only Marks Remark Function Cells with a very large nucleus and little cytoplasm Cells with granular cytoplasm and a lobed nucleus Large cells with a kidney-shaped nucleus [6] Examiner Only Marks Remark (b) The table below shows the red blood cell counts for a person living at sea level, and the same person after acclimatisation at high altitude in preparation for climbing Mount Everest. Red blood cell count/dm 3 At sea level 5.0 1012 After acclimatisation at high altitude 5.6 1012 (i) Describe how the partial pressure of atmospheric oxygen varies with altitude. __________________________________________________________ ________________________________________________________ [1] 4979 8 [Turn over (ii) Explain the advantage of having a higher red blood cell count at high altitude. Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ ________________________________________________________ [2] (iii) People such as the Quechua Indians in the Andes, who live permanently at high altitude, not only have increased red blood cell counts but possess other adaptations for life at high altitude. Describe one other adaptation to life at high altitude which might be expected, and explain how this adaptation aids their survival. __________________________________________________________ __________________________________________________________ __________________________________________________________ ________________________________________________________ [2] (iv) The increased production of red blood cells is due to the release of the hormone erythropoietin (EPO) in the body. Athletes can inject EPO to artificially stimulate the red blood cell count and so boost performance. Suggest one possible danger to the athlete of an artificially raised blood cell count. __________________________________________________________ ________________________________________________________ [1] 4979 9 [Turn over 6 A potometer is a device for investigating the rate of transpiration. Prior to setting up, the potometer and the stem of a leafy shoot are immersed in water. Under water, the bottom centimetre of the stem is cut off and the cut end inserted into the plastic tubing. The apparatus is removed from the water, a bubble of air allowed to enter the open end of the capillary tube and that end then inserted into a beaker of water. The completed set-up for a simple potometer is shown below. Examiner Only Marks Remark vaseline plastic tubing three-way tap syringe full of water capillary tube bubble of air beaker of water Reproduced with the permission of Nelson Thornes Ltd from Practical Advanced Biology by Tim King & Michael Reiss with Michael Roberts ISBN 0174483082 first published in 2001 (a) What assumption is made when this apparatus is used to investigate the rate of transpiration? ______________________________________________________________ ____________________________________________________________ [1] 4979 10 [Turn over (b) Explain each of the following. Examiner Only Marks Remark why it is necessary to cut the leafy shoot and fit it into the potometer under water ______________________________________________________________ ______________________________________________________________ how the bubble of air is introduced into the capillary tube ______________________________________________________________ ______________________________________________________________ why a syringe is attached ______________________________________________________________ ______________________________________________________________ why the set-up is left for 15 minutes before taking readings ______________________________________________________________ ____________________________________________________________ [4] 4979 11 [Turn over (c) The table below shows some results recorded using the apparatus. Examiner Only Marks Remark Distance travelled by bubble/mm Time/minutes Normal room conditions Covered with clear plastic bag Covered with black plastic bag 0 0 0 0 2 18 10 4 4 36 19 8 6 55 29 11 8 74 38 15 10 90 48 18 (i) Explain, as fully as possible, the results obtained. ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ ________________________________________________________ [3] (ii) In normal room conditions, the distance moved by the bubble was 90 mm during 10 minutes. The capillary tube has a cross sectional area of 0.8 mm2. Calculate the rate of movement in mm3 minute 1. (Show your working in the space below.) Answer _________ mm3 minute 1 [2] 4979 12 [Turn over (d) In experiments using a potometer it is usual to use the same shoot throughout. Give one limitation of using different shoots in the potometer when investigating the rate of transpiration. Examiner Only Marks Remark ______________________________________________________________ ____________________________________________________________ [1] 4979 13 [Turn over 7 Read the passage below and then use the information in the passage, and your own understanding, to answer the questions which follow. Ireland is one of the least wooded countries in Europe, even though forestry plantations have increased tree cover from less than 1% of land cover to about 10% in the last century. A new plan aims to increase this to 17% by 2030, mainly by planting new commercial forests at approximately 20,000 hectares per year. This increase represents a huge change in land use across Ireland, and has far-reaching economic, social and ecological consequences. The most widely planted species in these commercial forests is sitka spruce (Picea sitchensis). This is a non-native conifer, which maintains a canopy of needle-like leaves throughout the year. A policy change in the late 1990s promoted the use of broadleaf trees in plantations. The planting of ash (Fraxinus excelsior), which is a deciduous tree with a full canopy only during the summer months, has increased significantly and broadleaf trees now constitute 20% of new plantings. In a project investigating the diversity of plant species growing within these different woodland types, the plants were categorised as either bryophytes or as vascular plants. Bryophytes, mostly mosses, form a ground layer close to the soil surface as they require dampness. They are shade-tolerant plants. The vascular plants, ferns and flowering plants, form a herbage layer. These plants may be either shade-tolerant, mostly the ferns, or grow rapidly in early spring before the tree canopy closes out the light during the summer season. Examiner Only Marks Remark 5 10 15 20 (a) State two features of the kingdom Plantae. 1. ___________________________________________________________ 1. ___________________________________________________________ 2. ___________________________________________________________ 2. _________________________________________________________ [2] 4979 14 [Turn over (b) (i) Explain why ferns may be relatively abundant in both sitka spruce and ash woodlands. Examiner Only Marks Remark _________________________________________________________ _______________________________________________________ [1] (ii) Identify the niche occupied by most species of flowering plants in the ash woodland. _________________________________________________________ _______________________________________________________ [1] (c) The number of different species (species richness) of vascular plants and bryophytes was determined for each woodland type. The results are shown in the graph below. 30 vascular plants 20 Number of plant species in each woodland type bryophytes 10 0 Sitka spruce Ash Woodland type Describe the trends evident in the graph. Examiner Only Marks Remark ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ____________________________________________________________[3] 4979 15 [Turn over (d) (i) Explain how the diversity of animal species may be increased by greater plant species diversity. Examiner Only Marks Remark __________________________________________________________ ________________________________________________________ [1] (ii) Suggest how the introduction of a non-native conifer as the main forest plant has decreased animal diversity. __________________________________________________________ ________________________________________________________ [1] (e) Suggest one economic consequence [line 7] of increased commercial forests in Ireland. ______________________________________________________________ ____________________________________________________________ [1] (f) Briefly describe one strategy which encourages biodiversity and explain how this strategy conserves or improves biodiversity. _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ___________________________________________________________ [2] 4979 16 [Turn over Section B Examiner Only Marks 8 Remark Give an account of the co-ordinated sequence of events which result in the flow of blood through the heart during one cardiac cycle. [15] _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ 4979 17 [Turn over Examiner Only _________________________________________________________________ Marks Remark _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ 4979 18 [Turn over Examiner Only _________________________________________________________________ Marks Remark _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ _________________________________________________________________ 4979 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. 937-044-1 4979 20 [Turn over 4979.02 AB121IN1 GCE Biology Advanced Subsidiary (AS) New Specification Assessment Unit AS 2 Module 2: Organisms and Biodiversity Summer 2009 Source: Sinclair Stammers/Science Photo Library Photograph 2.3 (for use with Question 3)

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Additional Info : Gce Biology June 2009 Assessment Unit AS 2 Module 2: Organisms and Biodiversity - Revised
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