Explain how habitat loss, overexploitation, pollution, invasive species and climate change reduce populations and increase extinction risk in Cambridge A Level Biology questions.
Measurements of the surface temperature of land and oceans can be taken from locations around the world. The mean global surface temperature for land and ocean combined can be calculated for a fixed time period.
Scientists calculated:
- the mean global temperature for the twentieth century
- the mean global temperature for each decade (ten years) from 1880 to 2020.
The mean temperature for each decade was compared to the mean for the twentieth century. For each decade, the difference in temperature was calculated.
The calculated differences are shown in Fig. 10.2.
Fig. 10.2
Moose populations have decreased in North America since 1980.
Suggest and explain reasons for the decrease in moose populations.