Biodiversity and conservationIB Environmental Systems and Societies SL: Topic test

20 questions, 54 marks

IB Environmental Systems and Societies SL

Biodiversity and conservation topic test

Total 54 marks

Name

Class

Date

1
In the 1840s most peppered moths (Biston betularia) in the industrial city of Manchester, England, were pale with dark speckles. Soot from factories then darkened tree trunks and killed the pale lichens growing on them. By 1895 about 98% of the moths in Manchester were the dark form. Birds hunt the moths by sight, and experiments showed that moths resting on a background that matches their colour are eaten less often. After clean air laws reduced soot in the 1950s, the pale form became common again.
(a)
Which feature of the peppered moth population provides the raw material for natural selection?
[1 mark]
AAll the moths are the same colour
BMoths vary in colour from one individual to another
CBirds hunt the moths by sight
DThe moths live in a city
(b)
Which statement best explains why the dark form became more common in Manchester?
[1 mark]
AMoths changed colour during their lives to match the trunks
BDark moths survived and reproduced more often, passing on the trait
CSoot caused the moths to produce dark offspring
DPale moths migrated out of the city
(c)
Explain how overproduction and competition contributed to the change in the moth population.
[2 marks]
Total for question 1: 4 marks
2
Two meadows in the Swiss Alps were each sampled with the same number of quadrats. Each sample contained 100 flowering plants belonging to four species. In Meadow A there were 25 plants of each of the four species. In Meadow B there were 85 plants of one species and 5 plants of each of the other three species. Both meadows are grazed lightly by cattle in summer.
(a)
How does the species richness of Meadow A compare with Meadow B?
[1 mark]
AMeadow A is higher
BMeadow B is higher
CThe two meadows are not comparable
DThe two meadows are the same
(b)
Which statement about the meadows is correct?
[1 mark]
AMeadow B has the higher evenness and the higher Simpson's reciprocal index
BMeadow A has the higher evenness and the higher Simpson's reciprocal index
CMeadow A has the higher evenness but the lower Simpson's reciprocal index
DThe two meadows have the same evenness
(c)
Explain why the greater diversity of Meadow A may make it more resilient to disturbance.
[2 marks]
Total for question 2: 4 marks
3
A student sampled invertebrates on the floor of a mixed woodland in Poland by using five pitfall traps. The total catch of each species was: species P 6 individuals, species Q 4, species R 3, species S 2 and species T 1. The student used Simpson's reciprocal index, D = N(N − 1) ÷ Σn(n − 1), where N is the total number of individuals and n is the number of individuals of each species. A year later part of the woodland was thinned for timber and the student repeated the survey in the thinned area using the same method.
(a)
Calculate Simpson's reciprocal index for the first sample. Show your working.
[3 marks]
(b)
Explain how the index could be used to assess the effect of the thinning, and state two limitations of the index.
[4 marks]
Total for question 3: 7 marks
4
The vaquita (Phocoena sinus) is a small porpoise found only in the northern Gulf of California, Mexico. Its population fell from about 600 in 1997 to roughly 10 individuals in recent surveys, and the IUCN lists it as critically endangered. Vaquitas drown when they are caught in gillnets set to catch the totoaba, a large fish whose swim bladders are sold illegally for high prices in Asia. Mexico banned gillnets in the vaquita's range, but illegal fishing continues. Local fishing communities have few other sources of income.
(a)
Explain how direct and indirect human influences have led to the decline of the vaquita.
[6 marks]
(b)
Evaluate the usefulness of assigning the vaquita a global conservation status of critically endangered.
[6 marks]
Total for question 4: 12 marks
5
The Hawaiian crow, or ʻalalā (Corvus hawaiiensis), became extinct in the wild in 2002. The last wild birds lived in forest on the island of Hawaiʻi that had been cleared for grazing, and they were affected by introduced predators such as cats and mongooses and by avian diseases. A captive breeding programme has raised the population in zoos to over 100 birds. Since 2016 captive-bred birds have been released into a protected forest reserve where rats, cats and mongooses are trapped.
(a)
Which term describes the captive breeding of the ʻalalā?
[1 mark]
AIn situ conservation
BEx situ conservation
CHabitat-based conservation
DRewilding
(b)
Which action in the reserve is an example of active management of a habitat?
[1 mark]
ABreeding birds in a zoo
BMaking a captive birds register
CKeeping a gene bank of frozen cells
DTrapping introduced predators in the forest
(c)
Explain one advantage and one disadvantage of ex situ conservation for a species such as the ʻalalā.
[2 marks]
Total for question 5: 4 marks
6
A conservation agency in Kenya is planning to link two neighbouring savanna reserves for elephants. Each reserve is a roughly round area of 800 square kilometres with the two separated by 25 km of farmland. Elephants need large home ranges, and in each reserve a growing population is damaging the trees. Around the edge of each reserve, elephants raid farmers' crops. Planners propose a strip of protected land, a wildlife corridor, between the reserves.
(a)
Which shape of reserve is generally best for conserving species with large ranges?
[1 mark]
AA large, compact reserve with a low edge-to-area ratio
BA large reserve with a high edge-to-area ratio
CA small, elongated reserve
DSeveral tiny reserves far apart
(b)
What is the main ecological benefit of a wildlife corridor between the reserves?
[1 mark]
AIt reduces the area available to elephants
BIt stops elephants moving into farmland
CIt allows animals to move between populations, increasing gene flow
DIt removes the need to understand the species' biology
(c)
Explain why the size of a nature reserve affects its ability to conserve large mammals.
[2 marks]
Total for question 6: 4 marks
7
The mountain gorilla (Gorilla beringei beringei) lives in the Virunga mountains of Rwanda, Uganda and the Democratic Republic of the Congo. A census in 1981 counted 254 gorillas in the Virunga massif, and the census in 2016 counted 604. The IUCN listed the subspecies as critically endangered until 2018, when it was reclassified as endangered. Conservation includes armed ranger patrols against poachers, veterinary care for sick animals, and regulated gorilla tourism, with permits that fund the parks and local communities. Rangers have been killed in the area by armed groups.
(a)
Calculate the percentage increase in the number of gorillas in the Virunga massif between 1981 and 2016. Give your answer to one decimal place.
[3 marks]
(b)
Explain how conservation status helps conservation, and discuss why the gorilla's recovery may not be secure.
[4 marks]
Total for question 7: 7 marks
8
Yellowstone National Park in the United States lost its wolves in the 1920s after hunting. In 1995 and 1996, 31 wolves from Canada were released into the park. Elk numbers, which had risen in the absence of predators, fell and elk changed where they grazed. Young willow and aspen trees began to recover along rivers, beavers returned to some streams and songbirds increased. Wolf watching now brings many visitors to the park. Some ranchers outside the park have lost livestock to wolves and have campaigned against the reintroduction.
(a)
Explain how the reintroduction of wolves is an example of rewilding.
[6 marks]
(b)
Discuss how different environmental perspectives and value systems could influence views on the reintroduction of wolves to Yellowstone.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).