Question 1(d)
[Maximum number: 3]
Many species of spider are thought to be endangered.
State three reasons why animal species such as spiders become endangered.
1
2
3
IGCSE Biology Extended 20.4.3—Organisms become endangered or extinct Topic Practice
20.4.3—Organisms become endangered or extinct
• Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced species
Question 3(c)(i)
[Maximum number: 3]
Cheetahs, Acinonyx jubatus, are carnivores found in the dry grasslands and woodlands of southern Africa. Cheetahs hunt for food during the day. They eat deer and antelope.
The cheetah is the fastest mammal on land but can only run at high speed (sprint) over a short distance. Its hunting strategy is to creep up on prey and then sprint to catch them.
Fig. 3.1 is a photograph of a cheetah in its natural habitat.
Fig. 3.1
Cheetahs are at risk of becoming endangered.
Suggest why the cheetah is at risk of becoming endangered.
Question 4(a)(i)
[Maximum number: 3]
Climate change is one reason why a plant species could become endangered.
State other reasons why a plant species could become endangered.
Question 5(b)
[Maximum number: 3]
The giant quiver tree, Aloe pillansii, shown in Fig. 5.1, is an endangered species.
These long-lived trees grow in harsh environments. Some populations of A. pillansii are found within the Richtersveld National Park, but one population is found just outside on a mountain called Cornell's Kop in southern Africa.
Fig. 5.1
Suggest three reasons why the giant quiver tree is an endangered species.
1
2
3
Question 4(a)
[Maximum number: 5]
There are three species of rhinoceros in Asia. Fig. 4.1 shows an Indian rhinoceros, Rhinoceros unicornis, in a national park being observed by tourists who are riding on an elephant.
Fig. 4.1
The International Union for Conservation of Nature (IUCN) collects data on animal species and places them into categories based on estimated numbers.
Table 4.1 summarises the conservation status of the three species of rhinoceros, as available in 2020.
Table 4.1
Outline the reasons why large mammals, such as some species of rhinoceros, are endangered.
Question 39
[Maximum number: 1]
What are reasons why species become endangered?
A
habitat destruction, hunting and introduced species
B
habitat protection, introduced species and monitoring
C
habitat destruction, hunting and captive breeding programmes
D
hunting, pollution and seed banks
Question 39
[Maximum number: 1]
What are two reasons for organisms becoming endangered?
1 habitat destruction
2 monitoring
3 education
4 pollution
5 captive breeding programmes
A
1 and 4
B
1 and 5
C
2 and 3
D
3 and 4
Question 6(b)
[Maximum number: 2]
Fig. 6.1 shows a boreal toad, Anaxyrus boreas. This toad is listed as an endangered species.
Fig. 6.1
One reason for the boreal toad's recent decrease in population is a disease caused by chytrid fungus.
State two reasons other than disease that could cause the boreal toad to become endangered.
1
2
Question 6(d)
[Maximum number: 2]
There are xerophytic forests which are threatened by human overexploitation. Suggest reasons why it is important to conserve xerophytic ecosystems.