Question 1
1
The incidence of white syndrome, an infectious disease of coral, was investigated in a six-year study on Australia's Great Barrier Reef. The map shows disease conditions on coral reefs at six study sites.
13 marks
Question 1(a)
1(a)
2 marks
Question 1(a)(i)
1(a)(i)
Identify the site with the highest incidence of diseased colonies.
Easystructured1 marks
Answer
Capricorn and Bunkers group;
Question 1(a)(ii)
1(a)(ii)
Deduce whether there is a trend in the incidence of white syndrome over the north-south range of latitude.
Mediumstructured1 marks
Answer
there is no clear trend;
Question 1(b)
1(b)
Satellites were used to record sea surface temperatures. The temperatures each week above a reef were compared with mean temperatures for that week between 1985 and 2004. If the sea surface temperature was \(1^{\circ} \mathrm{C}\) or more above the mean, this was recorded as a weekly sea surface temperature anomaly (WSSTA). The number of WSSTAs was calculated for the twelve months preceding the date on which a reef was surveyed for white syndrome. On each reef, the number of cases of white syndrome in a \(1500 \mathrm{~m}^{2}\) sample area was surveyed once per year. The table shows these cases in relation to numbers of WSSTAs and coral cover on the reef. Low coral cover was 0-24 % and high coral cover was 50-75 %.
4 marks
Question 1(b)(i)
1(b)(i)
Describe the evidence that is provided by the data in the table for the harmful effects of rising sea temperatures on corals.
Mediumstructured2 marks
Answer
a. effects (generally) increase with temperature anomalies/WSSTA; b. effects increase for all different coral covers OR in the 25-49 cover there is an anomaly/is not an increasing trend; c. harmful effect is higher in coral covers between1 50-75\% / vice versa; 2 max
Question 1(b)(ii)
1(b)(ii)
The researchers concluded that there was a threshold coral cover percentage, below which infection rates tended to remain fairly low. Using the data in the table, identify this threshold level.
Mediumstructured1 marks
Answer
50\% / 25\% / 49\% OR 25-49\% (coral cover);
Question 1(b)(iii)
1(b)(iii)
Suggest a reason for a larger percentage of corals being infected with white syndrome on reefs with a higher cover of corals.
Mediumstructured1 marks
Answer
a. the closer the corals are (to each other) the easier the transmission; b. other organisms in the community may act as vectors/carriers / OWTTE; 1 max
Question 1(c)
1(c)
The graphs show the relationship between the weekly sea surface temperature anomalies (WSSTA) and coral cover during two twelve-month periods (1998-99 and 2002-03), which were the warmest in the six-year study. Each dot represents one studied reef.
3 marks
Question (i)
(i)
Compare and contrast the data for 1998-1999 and 2002-2003.
Mediumstructured2 marks
Answer
c i Similarities a. similar range of cover in both periods OR weak correlation/no correlation in either; Differences b. higher WSSTA range/more WSSTA in 1998-1999 than 2002-2003 OR positive (2002-3) versus negative correlation (98-99) OR more coral reefs with very low \% of coral cover (0-20\%) in 2002-2003; Must respond with one similarity and one difference for full marks 2 max
Question (ii)
(ii)
Suggest a reason for the correlation between coral cover and WSSTA in 1998-1999.
Mediumstructured1 marks
Answer
c ii coral cover lower on reefs with higher temperature;
Question 1(d)
1(d)
Some scientists predict that, if humans continue to produce carbon dioxide at the current rate, the pH of the oceans will become more acidic. Suggest possible effects on the coral reefs.
Mediumstructured3 marks
Answer
a. corals would not be able to maintain their skeletons; b. (if coral reefs are lost) habitat will be lost; c. some organisms/coral can decline if the water becomes too acidified; d. coral bleaching could occur/become worse OR coral could expel their mutualistic alga/zooxanthellae; e. enzymes could be denatured; 3 max e real environmental conditions / larger scale investigations / more variables studied;
Question 1
1
Rice (Oryza sativa) is usually intolerant to sustained submergence under water, although it grows rapidly in height for a few days before dying. This is true for one variety, Oryza sativa japonica. The variety Oryza sativa indica is much more tolerant to submergence. Three genetically modified forms of O. sativa japonica, GMFA, GMFB and GMFC, were made using different fragments of DNA taken from O. sativa indica. The plants were then submerged for a period of 11 days. The heights of all the plants were measured at the beginning and at the end of the submergence period.
14 marks
Question 1(g)
1(g)
Evaluate, using all the data, how modified varieties of rice could be used to overcome food shortages in some countries.
Hardessay2 marks
Answer
genetically modified rice/rice with Sub1A is more tolerant to submersion; can withstand seasonal flooding/torrential rain; GMF/tolerant rice ensures greater harvest/provides more food during flooding;
Question 1
1
Ebola virus disease (EVD) is the disease in humans and other primates that is caused by the Ebola virus. Fruit bats are the reservoir for the virus and are able to spread the disease without being affected. Humans can become infected by contact with fruit bats or with people infected by the virus, their body fluids or equipment used to treat them. The table shows data for four African countries that were affected by the 2014-2015 Ebola outbreak.
12 marks
Question 1(b)
1(b)
Analysis of the data suggests that the number of deaths from EVD is not related to the total population size. State one piece of evidence from the data that would support this analysis.
Mediumstructured1 marks
Answer
country with biggest population/Mali has lowest number of deaths OR country with smallest population/Liberia has biggest number of deaths OWTTE
Question 3
3
0 marks
Question 3(a)
3(a)
Describe the role of the EDGE of Existence programme. Chimpanzees and bonobos are different species of primate. It is thought that neither species can swim. The map shows the relative locations of chimpanzees and bonobos in Africa. Evidence suggests that the level of the Congo River was lower during one period in the past. At this time, chimpanzees could have migrated across.
Easystructured2 marks
Answer
a. prioritizes globally endangered species for conservation; b. identifies species that have few close relatives/evolutionarily distinct; c. species recognised at a grassroots level/ program is run at a local level WTTE/Important for maintaining biodiversity; d. named relevant example of a species or EDGE program; d. Examples may include Chinese Giant Salamander (Andrias davidianus)/Pangolins (e.g., Sunda Pangolin Manis javanica)/ Aye-aye (Daubentonia madagascariensis) But any other correct and verified example is allowed 2 max
Question 4
4
Beavers (Castor fiber) have been reintroduced into many European countries. They cut down trees and use them as a source of food as well as for building their homes and dams.
structured0 marks
Question 4(b)
4(b)
Studies show that species richness of large invertebrates increases in the presence of beavers. Suggest reasons why biodiversity is important in an ecosystem.
Mediumstructured2 marks
Answer
a. high biodiversity provides more complex food webs/increased food sources OR low biodiversity leads to less complex food webs and reduced food sources; b. high biodiversity leads to a more stable ecosystem / more adaptability/sustainability OR low biodiversity leads to a less stable ecosystem / less adaptability/sustainability; c. high biodiversity leads to more resistance to change/damage OR low biodiversity leads to less resistance to change/damage; 2 max
Question 22
22
The dark areas of the map show the distribution of some species included in the EDGE of Existence programme. What is the reason these species have been included in the EDGE of Existence programme? They occupy similar niches threatened by invasive species. Their risk of extinction is higher as they live at the edge of ecosystems. Their populations are decreasing and there are few or no closely related species. They are keystone species in their ecosystems.
Easymcq1 marks
Answer
C
Question 23
23
The North Island giant moa (Dinornis novaezealandiae) went extinct some time between the arrival of humans in New Zealand and the 1800s. What do scientists believe to be the cause of this extinction? Deforestation New diseases Competition with other megafauna Overhunting
Easymcq1 marks
Answer
D
Question 23
23
What are causes for a global reduction in biodiversity? I. Increase in size of towns and cities II. Reclamation of degraded ecosystems III. Clearance of land for agriculture I and II only I and III only II and III only I, II and III
Easymcq1 marks
Answer
B
Question 23
23
What could minimize the loss of biodiversity? Increase the rate of deforestation Introduce species into new environments to control predation Reduce the use of renewable energy Rewilding of degraded ecosystems
Easymcq1 marks
Answer
D
Question 6
6
Insect pollinators are vital to maintaining the biodiversity of ecosystems, but they are threatened by some human actions. Some pollinators, such as honey bees (Apis mellifera), produce honey, which is rich in glucose.
structured0 marks
Question 6(b)
6(b)
List human actions that could threaten populations of insect pollinators such as bees.
Easystructured3 marks
Answer
a. use of pesticides/insecticides (which may kill/harm pollinators); b. urbanization; c. loss of habitat/change of land use (monocultural/intensive farming practices); d. use of herbicide or removal of "weeds" reducing food sources; e. introduction of alien species; For a. or d. the mention of a specific pesticide or herbicide would be ok. 3 max