[Source: D W Sims and V A Quayla (1998) Nature 393, pages ] (2)

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1 1. Basking sharks (Cetorhinus maximus) filter feed on zooplankton (small floating marine animals) in temperate coastal seas. Marine biologists recorded the swimming paths taken by two basking sharks about 8 km off the coast of Plymouth (UK). At the same time the densities of zooplankton (in g m 3 ) were recorded within 3 m of the swimming path of the sharks. [Source: D W Sims and V A Quayla (1998) Nature 393, pages ] Using the scale given, calculate the straight line distance, (i) from point A to point B; (ii) from point C to point D. (b) Outline the difference in the swimming behaviour between shark 1 and shark 2. (c) Using the data given, suggest reasons for the difference in the swimming behaviour of the two sharks. (3) (d) State two factors other than food which may affect the distribution of the basking sharks. (Total 8 marks) 1

2 2. Phenologists are biologists who study the timing of seasonal activities in animals and plants, such as the opening of tree leaves and the laying of eggs by birds. Data such as these can provide evidence of climate changes, including global warming. The date in the spring when new leaves open on horse chestnut trees (Aesculus hippocastaneum) has been recorded in Germany every year since The graph below shows the difference between each year s date of leaf opening and the mean date of leaf opening between 197 and 2. Negative values indicate that the date of leaf opening was earlier than the mean. The graph also shows the difference between each year s mean temperature during March and April and the overall mean temperature for these two months. The data for temperature was obtained from the records of thirty-five German climate stations. Difference in mean temperature / ºC Key: = temperature 1 3 = leaf opening Year [Source: Walther et al., Nature (22), 416, pages ] Difference in date of leaf opening / days Identify the year in which there was the (i) earliest opening of horse chestnut leaves; (ii) lowest mean temperature in March and April. (b) Use the data in the graph to deduce the following. (i) The relationship between temperatures in March and April and the date of opening of leaves on horse chestnut trees. (ii) Whether there is evidence of global warming towards the end of the twentieth century. From 1973 onwards phenologists in the Netherlands have been studying a population of great tits (Parus major) in a forest on the Hoge Veluwe. Nest boxes are checked every week to find out when the great tits lay their eggs and how many eggs they lay. Young birds are ringed when they are seven days old, to allow the reproductive success of their parents to be monitored. Great tits feed on arthropods, especially caterpillars. The phenologists found that the date of maximum caterpillar biomass each year in the forest could be estimated accurately using temperature records. The graphs below show the mean date of egg laying and the estimated date of maximum caterpillar biomass for each year from 1973 to

3 45 Mean date of egg laying / number of days after 31 March Mean estimated date of maximum caterpillar biomass / number of days after 31 March Year [Source: Visser, Noordwijk, Tinbergen and Lessells, Proceedings of the Royal Society of London, (1998), 265, pages ] (c) (i) Compare the date of egg laying with the date of maximum caterpillar biomass. (ii) Suggest an advantage to great tits of the difference in dates. (d) State the trend, shown in the graph, for the date of maximum caterpillar biomass. There was no statistically significant change in the date of egg laying between 1973 and 1995, but the phenologists found evidence that natural selection will eventually cause a change in the date of egg laying. (e) Explain how natural selection could cause a change in the date of egg laying in the population of great tits in the forest on the Hoge Veluwe. (Total 1 marks) 3

4 3. Sea water temperature has an effect on the spawning (release of eggs) of echinoderms living in Antarctic waters. Echinoderm larvae feed on phytoplankton. In this investigation, the spawning of echinoderms and its effect on phytoplankton was studied. In the figure below, the top line indicates the number of larvae caught (per 5 litres of sea water). The shaded bars below show when spawning occurred in echinoderms. = % to 25 % = 25 % to 75 % = 75 % to 1% The concentration of chlorophyll gives an indication of the concentration of phytoplankton. Note: that the seasons in the Antarctic are reversed from those in the northern hemisphere. Number of echinoderm larvae 8 % Spawning of echinoderm Sea temperature / C Log 1Chlorophyll concentration / mg m phytoplankton.1 Dec Mar Jun Sep Dec Mar Jun Sep Dec Sea temperature / C [Source: adapted from Stanwell-Smith and Peck, Biological Bulletin, (1998), 194, pages 44 52] State the trophic level of echinoderm larvae. (b) Identify the period during which the spawning of echinoderm lies between 25% and 75%. (c) Explain the relationship between the seasons and the concentration of phytoplankton. 4

5 (d) (i) Outline the effect of sea water temperature on echinoderm larvae numbers. (ii) Using the data in the figure, predict the effect of global warming on echinoderm larvae numbers. (Total 8 marks) 5

6 4. A population of bighorn sheep (Ovis canadensis) on Ram Mountain in Alberta, Canada, has been monitored since the 197s. Hunters can buy a licence to shoot male bighorn sheep on the mountain. The large horns of this species are very attractive to hunters, who display them as hunting trophies. Most horn growth takes place between the second and the fourth year of life in male bighorn sheep. They use their horns for fighting other males during the breeding season to try to defend groups of females and then mate with them. Younger males below the age of 6 are rarely able to compete with older males and so have fewer offspring. The graph below shows the size of the bighorn sheep population on Ram Mountain Population size [Source: Reprinted with permission from Macmillan Publishers Ltd: David W. Coltman, Undesirable evolutionary consequences of trophy hunting, Nature, vol. 426, issue 6967, pp , 23] Year Outline the trends in the population of bighorn sheep on Ram Mountain. The length of a male s horns is strongly influenced by its genes. It is therefore possible to predict the length of the horns of the future offspring of a male. An index of predicted horn length for the future offspring of each male on Ram Mountain has been calculated. Negative values indicate offspring with smaller horns than the mean of the population. Positive values indicate horns larger than the mean of the population. (b) Suggest one type of factor apart from genes, that could affect the length of a male s horns. The scattergraph below shows the relationship between the age to which a male lived (longevity) and the predicted horn length index of the male Longevity / years Predicted horn length index 6

7 (c) State the most frequent longevity (the mode). (d) (i) Outline the relationship between longevity and the predicted horn length index of the males. (ii) Suggest a reason for the relationship. The graph below shows the mean horn length of males on Ram Mountain, between 1975 and Mean horn length / cm Year (e) Explain the change in horn length shown in the graph in terms of the longevity of the males, the number of offspring that they produce and your understanding of the process of evolution. (3) (f) Suggest how the change in the size of horns could be reversed. (Total 1 marks) 7

8 5. Two species of sea snakes, Laticauda laticaudata and Laticauda colubrina, spend most of their lives living in the sea. They must be able to move, hunt and survive in the water, but for short periods they need to come ashore to breed. They inhabit some of the Pacific islands which have low coral cliffs that the snakes need to climb in order to get onto dry land for courtship, mating and laying eggs. Figure 1 Diagram to show a cross-sectional view of cliff used in the study vegetation Height 2.3m sea level [Source: Terrestrial locomotion in sea snakes: the effects of sex and species on cliff-climbing ability in sea kraits (Serpentes, Elapidae, Laticauda), X. Bonnet, I. Ineich and R. Shine, Biological Journal of the Linnean Society, August 25, vol. 85, issue 4, pages , Wiley-Blackwell. Used with permission.] The scientists studied the ability of snakes to climb the low cliff. They measured the body mass of the snakes and relative strength of the snakes. The mean results are shown in the bar charts below. Body mass/g Females Males Females Males Muscle strength / arbitrary units Key: L. laticaudata L. colubrina [Source: Terrestrial locomotion in sea snakes: the effects of sex and species on cliff-climbing ability in sea kraits (Serpentes, Elapidae, Laticauda), X. Bonnet, I. Ineich and R. Shine, Biological Journal of the Linnean Society, August 25, vol. 85, issue 4, pages , Wiley-Blackwell. Used with permission.] 5 State which sex of snake has the greater mean mass. (b) State which species of snake is the strongest. (c) The error bars represent standard deviation. Deduce which groups of snakes show the greatest variability in body mass. (d) For L. colubrina calculate the difference between the strength of the male and the female snakes. 8

9 The scientists placed male snakes onto the coral cliff near its base. They measured their ability to hold onto the coral cliff. The L. colubrina males climbed much faster than the males of L. laticaudata. The graph below shows the ability of snakes to cling to the coral cliff. 1 8 Key: L. colubrina L. laticaudata Snakes still clinging to the cliff / % Time / seconds [Source: Terrestrial locomotion in sea snakes: the effects of sex and species on cliff-climbing ability in sea kraits (Serpentes, Elapidae, Laticauda), X. Bonnet, I. Ineich and R. Shine, Biological Journal of the Linnean Society, August 25, vol. 85, issue 4, pages , Wiley-Blackwell. Used with permission.] (e) (i) Compare the ability of the two species of snake to cling to the cliff. (ii) Suggest two reasons for the difference in the ability of the snakes to cling to the cliffs for 12 seconds. (f) Discuss the advantages and disadvantages of body mass in these two species of snake. (3) (Total 11 marks) 9

10 6. The flavour of wines can be assessed quantitatively by a technique called descriptive analysis. Using this technique, judges can evaluate wines for the relative intensity of different flavours. The graph below shows flavour profiles for three inexpensive white wines. Relative intensities for six of the flavours are shown. The centre of this diagram corresponds to low intensity and the outer edge to high intensity. Butter Wine X Wine Y Wine Z Oak Citrus Vanilla Apple Caramel [Source: Modified from J M Yegge and A C Noble, Proc. ASEV 5 th Anniversary Annual Meeting, (2), American Society for Enology and Viticulture, Davis, CA] State the relative intensity of butter flavour in wine X. (b) Distinguish the flavours of wine X and wine Y. (c) Identify, giving reasons, which two wines are most similar in taste. D and E omitted 1

11 7. Tests were carried out on ten male cyclists to see if training at higher than normal temperatures improved their fitness. The cyclists were divided in to two groups, A and B. Their training schedules were as follows: Days 1 to 12 Group A and Group B train at 2 C Days 13 to 19 Group A trained at 2 C and group B trained at 37 C Day 2 Group A and Group B have their heart rate measured during a time trial Days 21 to 32 Group A and Group B train at 2 C Days 33 to 39 Group B trained at 2 C and group A trained at 37 C Day 4 Group A and Group B have their heart rate measured during a time trial. The graph below shows the average results of the time trial on days 2 and 4 for the cyclists. In both trials the cyclists had to cycle 4 km in exactly 9 minutes at 2 C, with their heart rate being measured every 5 minutes. State the time of the highest heart rate reached by the cyclists training at 37 C.... (b) State the heart rate of the cyclists training at 2 C after 5 minutes.... (c) Compare the results for the heart rate at each training temperature (3) (d) Discuss whether the results support the hypothesis that training at high temperatures improves cardiovascular fitness (e) Suggest why on days 33 to 39, both Group A and Group B trained at different temperatures from the temperature they trained at from Days 13 to (Total 8 marks) 11

12 8. Since 197 jogging has become an increasingly popular form of exercise, but the public concern over its harmful effects has been raised following reports of death during jogging. A randomly selected group of 4658 men in Copenhagen, Denmark, between the ages of 2 and 79, attended two examinations one in 1976 and the other in Jogging status was determined by asking the participants if they were joggers. The influence of jogging on the risk of death was measured. The results are shown in the table below. Factors, other than jogging, were also analysed. Factor Jogging at time of examinations Diabetes Smoking Income Duration of education Alcohol consumption per week No or at only one examination At both examinations No Yes No Yes Middle or high Low < 1 years >1 years < 21 drinks Abstainers > 21 drinks Relative risk of death [Source: P Schorn et al., British Medical Journal, 9 September 2, 321, pages 62 63] State the factor that causes the greatest risk of death in this group of men. (b) Using only the data given, outline the type of man that has the least risk of death. (c) Discuss the hypothesis that regular jogging is not associated with increased mortality in men, using the results obtained in Copenhagen. (3) (d) omitted 12