IB Biology HL A4.2 Conservation of biodiversity questions

Exam-style multiple choice and written questions with full markschemes. Check multiple choice answers straight away, or type, photograph or draw a written answer and get it marked.

Question 1

Multiple choiceMedium1 mark

A conservation team compares four candidate species. The tree shows their relationships and relative branch lengths; the status labels show whether each species is globally endangered. Which candidate best fits the EDGE programme’s conservation-prioritization rationale?

Species KNot globally endangeredSpecies LGlobally endangeredSpecies MGlobally endangeredSpecies NNot globally endangered012345678910Relative evolutionary history (units)
Show answer and explanation

Answer: B. EDGE prioritization considers both evolutionary distinctness and global endangerment. The tree shows that Species L has a longer branch not shared with close relatives than Species M: 5 units compared with 1 unit. Both are globally endangered, whereas Species K’s longer independent branch is labelled not globally endangered. Species L therefore fits both considerations.

A: selects the longest independent lineage but overlooks that Species K is not globally endangered.
C: uses the global-endangerment label but overlooks that Species M shares most of its recent lineage with Species N.
D: could result from misreading Species N’s status; it is not globally endangered and has only a short unshared branch.

Remember: EDGE combines evolutionary distinctness with global endangerment.

Question 2

Paper 2Hard16 marks

Ecologists surveyed the same twelve 1 ha woodland plots in 2012, 2018 and 2024. Expert teams used the same method, visited at the same time of year and spent the same amount of time surveying each plot. The table shows the numbers of individuals recorded for six native bird species. A zero indicates that no individuals of that species were recorded.

Species201220182024
A405070
B302412
C20144
D1072
E850
F200

A citizen-science portal also collected observations in the surrounding landscape. A record is one submitted sighting, not a count of unique species. The portal did not use fixed observer-hours or fixed locations, and sightings were not independently checked.

YearRecords submittedContributorsHabitat types sampled
20121 200803
20245 1006009

Other estimates for the same landscape were:

Measure20122024
Human population42 00059 000
Native woodland remaining / ha1 200780
Woodland converted to agriculture or settlement since 2012 / ha0420
Plots occupied by an invasive alien plant / 1217
(a)

Calculate the percentage change in recorded bird species richness between 2012 and 2024.

[2]
(b)

Describe how species richness and evenness changed in the bird survey between 2012 and 2024.

[3]
(c)

State one benefit of citizen-science observations and explain why the increase in portal records alone does not establish an increase in biodiversity.

[4]
(d)

A conservation group concludes that biodiversity in this landscape is recovering and that any decline in the bird survey was caused solely by human population growth. Evaluate whether the data support these conclusions.

[7]

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