Question 1
1
Coral reefs are among the most spectacular ecosystems on Earth. They support a rich diversity of life and provide economic benefits to the people who use them. In Papua New Guinea in the Pacific Ocean north of Australia the following data were collected. Coral cover is the percentage of the reef surface covered by live hard coral.
13 marks
Question 1(c)
1(c)
Suggest causes for the changes in ocean temperature.
Mediumstructured2 marks
Answer
a. increased carbon dioxide/methane in the atmosphere / carbon dioxide emissions from burning of fossil fuels / other specific source of a named greenhouse gas b. increased greenhouse effect / more heat/long wave radiation trapped in the atmosphere c. heat transfer from atmosphere to ocean / ocean absorbs heat from atmosphere No marks for increased CO2 in the oceans, global warming or climate change. The idea of an increase must be included, not just greenhouse effect or heat trapping. 2 max
Question 1
1
Global warming has changed both the thickness and surface area of sea ice of the Arctic Ocean as well as the Southern Ocean that surrounds Antarctica. Sea ice is highly sensitive to changes in temperature. Scientists have calculated a long-term mean for the surface area of sea ice in the Arctic and in the Southern Ocean around Antarctica. This mean value is used as a reference to examine changes in ice extent. The graph shows the variations from this mean (zero line) over a period of time.
14 marks
Question 1(a)
1(a)
State the trend in the surface area of sea ice in the Southern Ocean around Antarctica.
Mediumdata_response1 marks
Answer
increasing/positive trend/correlation;
Question 1(b)
1(b)
Distinguish between changes in the surface area of sea ice in the Arctic and Antarctica.
Mediumdata_response2 marks
Answer
a. in the Arctic ocean the surface area of sea ice has declined whereas in Antarctica the surface area has increased; b. the rate of change is greater for the Arctic than for Antarctica; c. there are greater fluctuations in the surface area of sea ice in Antarctica than in the Arctic; For mp a, it is acceptable if there is no comparative term such as "whereas" or "but";
Question 1(d)
1(d)
Describe the trends in the length of the sea ice season around the Antarctic Peninsula and in the Ross Sea.
Mediumdata_response2 marks
Answer
One mark for correct description of the trend off the Antarctic Peninsula and one mark for correct description for the Ross Sea; accept correct statements other than those listed in the scheme but do not award a mark for contradictions; marks can be awarded for correct statements about the sea ice season for Antarctica overall; Some students are referring to moving South in the Ross Sea when it is clear that they are moving North. If you can discern their intention, then give the BOD on this; Antarctic Peninsula: a. decrease/stable at the base of the peninsula / decrease in the area of the penguin colonies/West of the tip / increase/+1 above and below the peninsula / variable pattern; Ross Sea: b. sea ice is increasing / +1 in the Ross Sea / area below / North of the Ross Sea / lower Ross Sea / Southern part of Ross Sea/closest to the South pole is stable/no change to the length of the sea ice season/ variable pattern;
Question 1(e)
1(e)
The graphs show the changes in penguin population in three of the colonies shown on the map. Analyse the trends in colony size of the Adélie penguins in relation to the changes in the sea ice.
Harddata_response3 marks
Answer
a. (off AP) sea ice season has declined as has penguin population; b. colony 2 and 3 sea ice season has not declined and population increased; c. colony 3 increase in population and growing length of sea ice season; d. colony 2 has stable / increasing numbers and sea ice season is not changing; e. colony size and sea ice season length/area are correlated; f. Population numbers for colony 1 and 3 the same at start of study but both experience a big (opposite change); Accept answers that refer to "sea ice" or "sea ice area".
Question 1(f)
1(f)
Discuss the use of Adélie penguins in studying the effects of global warming.
Hardessay3 marks
Answer
a. global warming leads to climate / environmental change; eg temperature change / ice melting b. stable ice associated with stable population / no climate change; c. ice changes associated with population changes; d. changes in penguin population size can indicate climate change / global warming; e. example of how climate change can alter population; eg prey availability / habitat loss; f. not all species will be affected in the same way (so care needed in applying conclusions more widely) g. there is information on changes of population over the past 35000 years;
Question 1
1
The black-legged tick (lxodes scapularis) is an arthropod which sucks blood from humans and other mammals. It is encountered mainly in wooded and semi-wooded areas. Some ticks can be infected by the bacterium Borrelia burgdorferi. When a tick bites a human, the bacterium is often introduced, causing Lyme disease. Lyme disease is a public health problem in North America and, if left untreated, can cause important neurological impairment. The diagram represents the two-year life cycle of a tick.
13 marks
Question 1(c)
1(c)
Scientists fear that global warming will change the distribution range of ticks. The graphs show the developmental stages of ticks throughout seasons in a densely human-populated area of south-eastern Canada, surrounded by woods (circled on the map). Values are already established for 2000 and are predicted for 2080. Identify the month when small birds had the greatest chance of being infected by B. burgdorferi bacteria in the year 2000 and the month when they would be most likely to become infected according to the 2080 predictions. 2000: 2080:
Mediumstructured1 marks
Answer
«2000» August AND «2080» July Both required.
Question 1(d)
1(d)
Using the life cycle diagram and the graph for the year 2000, analyse the distribution of adult ticks throughout the different seasons.
Mediumstructured2 marks
Answer
\(а\) adults present through autumn and winter «according to the life cycle diagram» OR some adults «must» survive winter «despite graph suggesting zero» Each mark point, requires month or season. Jan - Mar = winter Apr - Jun = spring Jul - Sep = summer Oct - Dec = autumn = fall Do not accept that there are the lowest number or no adults in winter. 2 max b adults peak in October «& November»/in autumn/between September and December c adults die after laying eggs in winter/beginning of spring d smaller peak/10\% versus 55\% peak/smaller numbers of adults in April/spring e adults absent from June to September/summer
Question 1(e)
1(e)
Evaluate the effect of the change in distribution of the different life stages of ticks on the spread of Lyme disease in south-eastern Canada.
Hardstructured3 marks
Answer
\(а\) nymphs present through most of year/longer period/from March to November/through spring and summer «so more risk of infection» 3 max b more adults in winter/in January/February so more risk of infection then c infection will be possible through more/most months of/throughout the year d Lyme disease likely to/will increase
Question 1
1
PanI is a gene in cod fish that codes for an integral membrane protein called pantophysin. Two alleles of the gene, \(\operatorname{PanI}{ }^{\mathrm{A}}\) and \(\operatorname{PanI}{ }^{\mathrm{B}}\), code for versions of pantophysin, that differ by four amino acids in one region of the protein. Samples of cod fish were collected from 23 locations in the north Atlantic and were tested to find the proportions of PanI \({ }^{\mathrm{A}}\) and PanI \({ }^{\mathrm{B}}\) alleles in each population. The results are shown in pie charts, numbered 1-23, on the map below. The proportions of alleles in a population are called the allele frequencies. The frequency of an allele can vary from 0.0 to 1.0 . The light grey sectors of the pie charts show the allele frequency of PanI \({ }^{\mathrm{A}}\) and the black sectors show the allele frequency of PanI \({ }^{\mathrm{B}}\).
10 marks
Question 1(f)
1(f)
Using the data in this question, predict the effects of global warming on cod fish populations.
Hardstructured2 marks
Answer
\(\quad \operatorname{PanI} \mathrm{I}^{\mathrm{A}} \operatorname{PanI} \mathrm{I}^{\mathrm{A}}(\operatorname{cod})\) may spread further north / PanI \(\mathrm{I}^{\mathrm{B}} \operatorname{PanI} \mathrm{I}^{\mathrm{B}}(\operatorname{cod})\) may move/retreat further north; numbers of \(\operatorname{PanI} \mathrm{I}^{\mathrm{A}} \operatorname{PanI} \mathrm{I}^{\mathrm{A}}(\operatorname{cod})\) may increase / frequency of \(\operatorname{PanI} \mathrm{I}^{\mathrm{A}}\) allele may increase; PanI \(^{\mathrm{B}}\) PanI \(^{\mathrm{B}}(\operatorname{cod})\) may become extinct / frequency of PanI \(^{\mathrm{B}}\) allele may decrease;
Question 1
1
Bottlenose dolphins (Tursiops truncatus) inhabit almost all tropical and temperate oceans between \(45^{\circ} \mathrm{N}\) and \(45^{\circ} \mathrm{S}\). Over a two-year period, aerial surveys were carried out to investigate the seasonal distribution of these animals along the mid-Atlantic and eastern coastal waters of the USA. Sightings were recorded using a global positioning system (GPS) while flying parallel to the coast approximately 500 m offshore. The diagram below shows a map of the section of coast surveyed. The bar graph shows the seasonal data for summer and winter at the corresponding latitudes ( \({ }^{\circ} \mathrm{N}\) ). A total of 5431 bottlenose dolphins were sighted during these surveys.
11 marks
Question 1(f)
1(f)
Explain how an increase in water temperature due to global warming could affect the distribution of bottlenose dolphins along the eastern coast of the USA.
Hardstructured2 marks
Answer
a. may migrate/move range further north; b. migrate to area with cooler/suitable water temperature; c. ocean currents may change; d. most productive waters/food supply may be further north; e. distribution more spread out (due to warmer waters in more areas);
Question 2
2
Average human internal (core) body temperature is \(36.4^{\circ} \mathrm{C}\), with slight variations between day and night. The average surface temperature of the Earth in the 20th century was \(13.9^{\circ} \mathrm{C}\). It has now risen to \(14.8^{\circ} \mathrm{C}\).
structured0 marks
Question 2(b)
2(b)
Explain how the burning of fossil fuels has contributed to the increase in the Earth's temperature.
Mediumstructured2 marks
Answer
a. \(\quad \mathrm{CO}_{2}\) is released/is a greenhouse gas; b. long wave radiation/heat/infrared (emitted by the Earth) trapped/absorbed by \(\mathrm{CO}_{2}\); c. (so) heat retained in atmosphere; Do not award a mark for 'Earth's temperature is increased' as this is in the question. b. Do not accept 'reflected back' instead of trapped or absorbed and do not accept absorption of any type of radiation from the sun. The word 'heat' can be used for both marking points b. and c. but in b. the idea is heat retained by \(\mathrm{CO}_{2}\) the whereas the idea in c. is heat retention in the atmosphere. 2 max
Question 2(c)
2(c)
Melting polar ice due to global warming is reducing reflection of sunlight from the Earth. Identify with a reason whether this will result in positive or negative feedback.
Mediumstructured1 marks
Answer
a. positive feedback because warming causes melting of polar ice; b. positive feedback because less ice means less sunlight is reflected (lower albedo); c. positive feedback because more heat is absorbed by the Earth's surface which becomes warmer; 1 max
Question E1
E1
E1. European robins (Erithacus rubecula) migrate South in the autumn (fall) and North in the spring. They orient their direction of flight using the local magnetic field, which they detect through magnetoreceptors in the upper beak. The orientation of the birds in a captive environment was studied in spring and autumn, which are the times of year when the birds normally migrate. The response of the birds to green light, red light and total darkness was investigated. Triangles on the edge of circles indicate the mean direction flown by individual birds while the arrows indicate the overall mean direction of flight.
0 marks
Question E1(a)
E1(a)
Identify the season and light conditions which result in the strongest northerly direction flown by the robins. Season: Light conditions:
Harddata_response1 marks
Answer
E1. (a) spring, green light ..... [1] Both required for [1].
Question E1(b)
E1(b)
Distinguish between the effect of red light and green light on the behaviour of the robins in spring and autumn (fall).
Harddata_response2 marks
Answer
in green light birds migrate North in spring but South in autumn; in red light birds orientate (North) West in both autumn and spring; ..... [2]
Question E1(c)
E1(c)
Based on the results of these experiments, suggest one possible conclusion that could be drawn regarding the effect of red light on the behaviour of robins.
Harddata_response1 marks
Answer
in red light birds do not migrate in the normal pattern/direction; red light disorientates the birds/interferes with the functioning of magnetoreceptors; red light has (almost) the same effect as total darkness / birds do not see in red light;
Question E1(d)
E1(d)
Using the data in the diagram, deduce with a reason, whether European robins migrate during the daytime or at night.
Harddata_response2 marks
Answer
during daytime; direction of migration is not normal/wrong orientation in darkness; ..... [2]
Question E1(e)
E1(e)
Scientists anesthetized the beaks of some robins in order to deactivate the magnetoreceptors. Predict how this would affect their orientation in red light.
Harddata_response1 marks
Answer
no effect; may become (even) more random; ..... [1 max]
Question 3
3
11 marks
Question 3(a)
3(a)
Explain how the following influence the enhanced greenhouse effect.
3 marks
Question 3(a)(i)
3(a)(i)
Reforestation of desert
Easystructured1 marks
Answer
decreases \(\mathrm{CO}_{2}\) concentration lowering greenhouse effect as trees/plants act as a carbon sink/photosynthesis absorbs \(\mathrm{CO}_{2}\) / OWTTE
Question 3(a)(ii)
3(a)(ii)
Change in energy source from fossil fuels to solar energy
Easystructured1 marks
Answer
solar energy reduces greenhouse gas emissions as fossil fuels are not burned lowering the effect / OWTTE
Question 3(a)(iii)
3(a)(iii)
Increase in the production of methane
Easystructured1 marks
Answer
(through its release/pollution by) methane can enhance the greenhouse effect since it is a greenhouse gas / other valid answer
Question 2
2
The graph shows the mean annual changes in global temperatures between 1880 and 2014. The mean temperature from 1951 to 1980 was used as the value of zero change in temperature.
0 marks
Question 2(c)
2(c)
Explain how increased carbon dioxide in the air leads to the greenhouse effect.
Mediumstructured3 marks
Answer
a. short wave radiation from sun passes through atmosphere/is not absorbed by \(\mathrm{CO}_{2}\); b. infrared/long wave (radiation)/heat emitted from/released from (surface of) Earth; c. \(\mathrm{CO}_{2}\) in the atmosphere absorbs infrared/long wave (radiation) / heat cannot pass through the greenhouse gases; d. this results in warm/increased temperatures on Earth/global warming; 3 max
Question 15
15
How do greenhouse gases contribute to global warming? A. They destroy the ozone layer, allowing radiation to reach the Earth's surface. B. They prevent radiation from the Earth escaping into space. C. They trap short wavelength radiation in the atmosphere. D. They are a product of combustion, which generates heat.
Easymcq1 marks
Answer
B