IB ESS HL 3.002.1 Threats to Biodiversity Question Bank
Analyse habitat loss, overexploitation, pollution, climate change and other threats to biodiversity.
- Syllabus
- First assessment 2026
- Course
- ESS HL
- Level
- HL
Analyse habitat loss, overexploitation, pollution, climate change and other threats to biodiversity.

Figure:Global biodiversity extinction-risk categories

Figure:Changes in species extinction risk from 1980 to 2015
Outline two reasons why amphibians have the highest approximate percentage of threatened species, as shown in the extinction-risk chart shown above.
a. They require both aquatic and terrestrial habitats/specialised niches so more likely to be affected by habitat loss/limitations;
b. They have permeable/soft skin more vulnerable to disease/UV/pollution;
c. Few amphibians have great public/charismatic appeal attracting protection/conservation efforts;
d. They generally have very limited parental care so offspring more vulnerable / high mortality rate in offspring;
e. They often depend on small bodies of water that are particularly vulnerable to drought/global warming/human development of wetlands
Note: Only credit marks that are explicitly related to the vulnerability of amphibians. General factors such as habitat destruction, hunting or climate change alone are TV.
Outline three reasons why the trend for corals is different to the other categories shown in the species-extinction trend chart shown above.
corals ...
a. are sedentary/cannot migrate (to avoid pollution or other risks);
b. are r-selected species so high mortality rates (in planktonic phase);
c. (have delicate symbiotic relationship) highly sensitive to small changes in abiotic conditions;
d. are impacted worldwide through ocean acidification (causing bleaching);
e. are impacted worldwide by global warming/climate change /warmer waters (causing bleaching);
f. inhabit areas with high human polluting activity such as urban waste/agricultural run-off/oil spills/aquaculture;
g. have value as souvenirs/trophy/collectors' items;
h. are fragile/easily damaged unintentionally (by boats/nets/storms etc);
i. have very slow growth rates (in sedentary phase); j. have limited ranges/ocean depths/habitats where they can live;
Credit any response that is consistent with the increasing trend of extinction in corals.
Do not credit "pollution" alone there must be reference to a relevant source of pollutant as in MPf