IB Biology SL A4.2 Conservation of Biodiversity Questions

Practise IB Biology SL A4.2 with questions on biodiversity, conservation priorities, threats, ecosystem change and sustainable decisions.

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, using quadrats or transects and counts to quantify biodiversity change over time.
Identify a named anthropogenic extinction cause and explain how habitat conversion removes food, shelter and breeding sites.
Explain how forest fragmentation and environmental pressure such as temperature change biodiversity and reef or community condition.
Identify urbanisation, land clearance, agriculture, pollution and overexploitation as human drivers of biodiversity loss.
Compare in situ and ex situ conservation using reserves, zoos, captive breeding, botanical gardens and seed banks.
Explain protected-area management, threat control and reintroduction as in situ conservation actions.
Evaluate biological control by naming target and control organisms and weighing selectivity, food-web risk and spread.
Explain how EDGE combines evolutionary distinctiveness with extinction risk to justify conservation priorities.

Covered syllabus points

A4.2.1—Biodiversity definition A4.2.2—Current vs. past biodiversity A4.2.3—Anthropogenic species extinction A4.2.4—Ecosystem loss causes A4.2.5—Evidence for biodiversity crisis A4.2.6—Causes of biodiversity crisis A4.2.7—Conservation approaches A4.2.8—EDGE of Existence programme

[Maximum number: 2]

The tundra ecosystem in Finnish Lapland has a short growing season and a mean temperature of $-2.0^{\circ} \mathrm{C}$ . It is also naturally grazed by herbivores such as reindeer (Rangifer tarandus). Different quadrats were set up to include and exclude the reindeer in both normal and warmed temperatures. Open-topped warming chambers were used to heat both the soil and air in the warmed quadrats. The graph shows the changes in plant richness over five years.

(a)

State what is meant by species richness.

[ 1 ]

(b)

Suggest how the results of this experiment can be used in the planning of in situ conservation programmes for tundra plant species.

[ 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.

Key: ○ 1977 to 1989 (early period) - 1997 to 2002 (late period)

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

No evidence that there are fewer species.
Difficult to compare as more trawls in the early period / early period of longer duration than late period.
Diversity may have increased from around $2000\mathrm{~m}$ to $4000\mathrm{~m}$ / outliers for greater species diversity are all late period.
Not enough details about time of year/duration of trawls.
Accept any other valid argument.
Do not accept answers stating only "not enough data".

[Maximum number: 1]

The North Island giant moa (Dinornis novaezealandiae) went extinct some time between the arrival of humans in New Zealand and the 1800s.

What do scientists believe to be the cause of this extinction?

Deforestation

New diseases

Competition with other megafauna

Overhunting

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Covered syllabus points

Question 1

Question (a)

Question (b)

Question 2

Question 3