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IB Biology HL A4.2 Conservation of Biodiversity Questions

Practise IB Biology HL A4.2 with evidence-led questions on biodiversity loss, conservation priorities, ecosystem threats, restoration and sustainability.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Distinguish species richness from evenness and calculate Simpson’s reciprocal diversity index from community counts, showing the working.
  • Interpret Simpson’s reciprocal index together with richness and evenness to compare biodiversity between communities or sampling periods.
  • Explain how human activity causes biodiversity loss through named species extinction and habitat conversion that removes food, shelter and breeding sites.
  • Identify human drivers of biodiversity loss and explain how a named invasive alien species can outcompete or disrupt native species.
  • Compare in situ and ex situ conservation, including reserves, zoos, captive breeding, botanical gardens, seed banks and reintroduction.
  • Explain active in situ management through protected areas, monitoring, anti-poaching, threat control and reintroduction.
  • Evaluate biological control using a named target and control organism, including selectivity, ecosystem risk and containment.
  • Explain reserve biogeography and wildlife corridors using area, edge effects, connectivity, movement and genetic exchange.
  • Explain how EDGE combines evolutionary distinctiveness with extinction risk to justify conservation priorities.

Covered syllabus points

A4.2.1—Biodiversity definitionA4.2.2—Current vs. past biodiversityA4.2.3—Anthropogenic species extinctionA4.2.4—Ecosystem loss causesA4.2.5—Evidence for biodiversity crisisA4.2.6—Causes of biodiversity crisisA4.2.7—Conservation approachesA4.2.8—EDGE of Existence programme

Question 1

[Maximum number: 3]

Question (a)

(a)

Distinguish between in situ and ex situ conservation.

[ 1 ]

Question (b)

(b)

Outline one reason for the extinction of a named animal species.

[ 1 ]

Question (c)

(c)

State one use of the Simpson index in ecology.

[ 1 ]

Question 2

[Maximum number: 2]

Knowledge of deep-water fish is important for fisheries and marine reserve management. Scientists analysed data from scientific trawls made from 1977 to 1989 (early period) and from 1997 to 2002 (late period). These were at depths from 800 m to 4800 m in the Porcupine Seabight and Porcupine Abyssal Plain area southwest of Ireland. The graphs represent the abundance of fish and the number of species for each of these trawls.

Two scatter plots against trawl depth, approximately 800–4800 m: fish abundance in thousands per square kilometre and number of species per trawl. Open circles represent 1977–1989 and crosses represent 1997–2002.

Discuss the evidence in these data for a decline in the biodiversity of fish between the early period and the late period.

Question 3

[Maximum number: 1]

The satellite images show changes in the area covered by forest, much of which is mixed dipterocarp forest, on the island of Borneo in Southeast Asia.

Figure for Question 3 — IB Biology HL

Which human activities are most likely to have caused the changes shown in the map?

A

Logging and palm oil plantation

B

Logging and rewilding

C

Mining and afforestation

D

Afforestation and palm oil plantation

Question 4

[Maximum number: 1]

State one use of the Simpson index in ecology.

Question 5

[Maximum number: 1]

Outline one reason for the extinction of a named animal species.

Question 6

[Maximum number: 1]

The graph shows the change in forest area in Greater Mekong countries in Southeast Asia between 1973 and 2009. This was mainly due to deforestation.

Forest area in thousands of hectares plotted from 1973 to 2009 for Myanmar, Thailand, Laos and Cambodia, with distinct line styles for each country.

State one cause of the current biodiversity crisis, other than deforestation.

Question 7

[Maximum number: 1]

Distinguish between in situ and ex situ conservation.

Question 8

[Maximum number: 2]

The graph shows the change in forest area in Greater Mekong countries in Southeast Asia between 1973 and 2009. This was mainly due to deforestation.

Forest area in thousands of hectares plotted from 1973 to 2009 for Myanmar, Thailand, Laos and Cambodia, with distinct line styles for each country.

The EDGE of Existence programme measures Evolutionary Distinctness (ED) and Globally Endangered status (GE).

Outline the importance of the EDGE of Existence programme.

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