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.

55 questions in this syllabus scope, with question parts counted together.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam analysis

HL · 2010–2025
Papers with this topic21 / 117in the analysed sample
Latest appearanceNovember 2025
Tagged question parts35
Paper types5

Most tested objectives

  1. A4.2.7—Conservation approaches16 papers
  2. A4.2.1—Biodiversity definition5 papers
  3. A4.2.4—Ecosystem loss causes4 papers
  4. A4.2.6—Causes of biodiversity crisis3 papers
  5. A4.2.2—Current vs. past biodiversity1 paper

Common question formats

  • Definition or recall
  • Calculation
  • Data analysis
  • Evaluation
  • Process explanation
  • Extended response

Recent exam appearances

November 2025Paper 1A HL · TZ3Q34[ 1 ]
May 2025Paper 2 HL · TZ2Q6(a), 6(b), 6(c)(i)[ 5 ]
May 2025Paper 2 HL · TZ1Q7(c)[ 2 ]

117 papers analysed · Tagging incomplete

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

Exam points

  • Identify ecosystem, species and genetic diversity as forms or levels of biodiversity.
  • Distinguish species richness from evenness when describing community diversity.
  • Calculate or interpret Simpson’s reciprocal index to compare species diversity between communities.

Question 1

[Maximum number: 1]

The Living Planet Index published by the World Wildlife Fund (WWF) tracks the state of global biodiversity by measuring the population sizes of thousands of vertebrate species around the world. The 2018 index shows an overall decline of 60 % in population size between 1970 and 2014. The chart shows the main threats to each taxonomic group in 2018.

Birds

Birds

Distinguish between species richness and evenness as components of biodiversity.

Exam points

  • State the estimate of about 9 million species and note that many remain undescribed.
  • Use fossils and radiometric dating as incomplete evidence of past biodiversity.
  • Compare current and past species diversity cautiously because fossil gaps make the result uncertain.

Question 1

[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.

Figure for Question 1 — IB Biology HL

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

Exam points

  • Explain how human activity contributes to the current sixth mass extinction.
  • Link hunting, habitat change or resource use to extinctions such as the North Island giant moa.
  • Explain how removing the Caribbean monk seal as a top predator can alter food webs.

Question 1

[Maximum number: 1]

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

Exam points

  • Explain how logging and oil palm plantations cause loss of Borneo forest habitat.
  • Explain how climate, pollution and fishing contribute to ecosystem loss on the Great Barrier Reef.

Question 1

[Maximum number: 2]

The map shows the distribution of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) on either side of the Congo River as it flows towards the Atlantic Ocean in the Democratic Republic of Congo. Bonobos occupy the dense wet forest south of the Congo River, whereas chimpanzees occupy a forested habitat north of the river. Both species are descended from a common ancestor.

Figure for Question 1 — IB Biology HL

The bonobo is classified as an endangered species. Explain how deforestation could contribute to the decline in the population size of bonobos.

Exam points

  • Link population growth to rising demand for food, housing, energy and land.
  • Identify overexploitation, urbanisation, deforestation, agriculture, mining and pollution.
  • Explain how invasive lionfish or water hyacinth can outcompete or disrupt native species.

Question 1

[Maximum number: 3]

The graph shows the total number of alien species in marine ecosystems estimated by the European Environment Agency.

Figure for Question 1 — IB Biology HL

Discuss the global impacts of invasive alien species.

Exam points

  • Choose in situ or ex situ conservation in response to species needs and threats.
  • Describe protected areas, reserve design, corridors, active management and rewilding.
  • Describe zoos, captive breeding, botanic gardens, seed banks and tissue banks as ex situ methods.

Question 1

[Maximum number: 3]

Outline how ex situ strategies are used in conservation.

Exam points

  • Use phylogenetic uniqueness and IUCN extinction risk to prioritise evolutionarily distinct, endangered species.
  • Explain how EDGE prioritisation helps prevent disproportionate loss of evolutionary history.

Question 1

[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.

Figure for Question 1 — IB Biology HL

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

Outline the importance of the EDGE of Existence programme.

Question 1

[Maximum number: 4]

The Living Planet Index published by the World Wildlife Fund (WWF) tracks the state of global biodiversity by measuring the population sizes of thousands of vertebrate species around the world. The 2018 index shows an overall decline of 60 % in population size between 1970 and 2014. The chart shows the main threats to each taxonomic group in 2018.

Birds

Birds

Question (a)

(a)

Suggest a reason for the loss of bird habitats.

[ 1 ]

Question (b)

(b)

Outline how in situ conservation may help preserve populations of amphibians.

[ 2 ]

Question (c)

(c)

Distinguish between species richness and evenness as components of biodiversity.

[ 1 ]

Question 2

[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 ]
All question bank results loaded