Date | November 2018 | Marks available | 3 | Reference code | 18N.1.SL.TZ0.10 |
Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
Command term | Explain | Question number | 10 | Adapted from | N/A |
Question
Figure 7(a): Fact file on North American beavers
- 1 family per square km of river.
- Live in family groups, with 2 adults and up to 3 young (kits) born each year between April and June.
- Mortality rates are high due to severe weather, lack of suitable habitats and predation.
- North American beaver population:
- estimated at 250 million before fur trade hunting
- today approximately 9 million.
- Feed off tree bark.
- Construct lodges from wood and mud:
- a safe place for eating, sleeping, and raising young
- remain in lodges during winter
- protect their own lodge from other beavers.
- Beavers are being reintroduced in Europe to help restore wetlands.
[Source: adapted from www.sbaa.ca, www.ecology.info, www.tobyhemenway.com and http://acs7.cortland.edu]
The resource booklet provides information on Algonquin Provincial Park in Canada. Use the resource booklet and your own studies to answer the following.
Figure 10(b): Algonquin wolf pack territories and protected areas
With reference to Figure 7(a), outline one reason why there are more beaver remains in wolf faeces during summer.
The number of wolves in Algonquin Provincial Park is estimated to be between 250 and 1000. Outline two reasons why it is so difficult to estimate the number of wolves accurately.
With reference to Figure 10(b), explain the threats to the future existence of a small and sustainable population of wolves as a result of their protection in limited area.
Markscheme
beavers remain in lodges in winter so they are unavailable as a food source / harder for wolves to catch them / easier to spot beavers in summer when they are out of their lodges;
other species (eg moose) are easier to catch in winter;
other prey of wolves like snowshoe hare or foxes may be harder to catch in summer;
young are out in summer and are more vulnerable/easily caught;
density of population higher in summer following breeding.
Do not accept only “beavers breed in the summer” or “beavers remain in lodges in winter”.
This question requires “Resource Booklet - Nov 2018 SL paper 1”, available under the "your tests" tab > supplemental materials.
remote wilderness areas so hard for scientists to spot them easily / densely wooded so not easily visible from the air;
large territorial range (35 km2)/highly mobile so hard to locate;
wolves are nocturnal/hunt at night/sleep during the day and therefore difficult to spot;
look very similar to coyotes so hard to identify accurately;
lack of long-term records to use as baseline data;
camouflaged so hard to see especially in winter;
seasonal fluctuations in numbers.
Do not accept “wolves are dangerous/predators/migrate”.
Do not accept “wolves are mobile so use of quadrat method is not effective” or “use of capture, mark, release, recapture method is not suitable (as it may harm the wolves)”.
Do not accept only “wolves look similar to coyotes / have large territorial range”.
This question requires “Resource Booklet - Nov 2018 SL paper 1”, available under the "your tests" tab > supplemental materials.
if the range overlaps with areas outside of Algonquin Provincial Park, ie not protected, the wolf is at risk of being hunted / may be mistaken as coyotes in the buffer zone and killed by accident;
genetic isolation may occur as there may be no mixing with wolf populations from outside of Algonquin Provincial Park;
restricted gene pool can lead to less resistance to diseases;
high population density increases risk of diseases spreading;
wolves may end up competing for territory/food with each other leading to higher mortality/limiting population growth / increase in intraspecific competition;
concentrated population is more prone to high losses during event of wildfires/natural disasters.
Examiners report
Many candidates gave responses that were too vague to be credited. For example, a common error was not to link beavers remaining in lodges to reduced predation by wolves during the winter.