36 exam-style questions on Evolution and speciation — topic A4.1 of Unity and diversity in the IB Biology syllabus — with answers and explanations. Samples below; the full set is free with an account.
In the binomial name Homo sapiens, the first word (Homo) is the
Answer: genus
Binomial nomenclature gives genus (capitalised) then species (lower case); both are italicised.
Which of the following is the best example of evidence for evolution provided by biogeography?
Answer: Related marsupials found only in Australia
The distribution of unique yet related species on isolated landmasses reflects descent with modification following geographic isolation, the core of biogeographical evidence.
The pentadactyl limb of mammals, amphibians and reptiles shows the same underlying bone arrangement despite different functions. This is evidence for evolution because these limbs are:
Answer: Homologous, from a common ancestor
The same underlying bone arrangement adapted to different functions shows the limbs are homologous: inherited from a common ancestor and modified by divergent evolution. Analogous structures look alike through convergent evolution but have different origins.
A single population of finches becomes divided by a new mountain range and the two groups evolve into separate species unable to interbreed. This is an example of:
Answer: Allopatric speciation
Allopatric speciation results from a geographic barrier that splits a population, preventing gene flow so the isolated gene pools diverge.
During industrial melanism in the peppered moth, which selection pressure favoured dark moths in polluted areas?
Answer: Predation by birds on pale moths on darkened trees
On soot-darkened trees, pale moths were more visible and eaten by birds, so predation selected for the dark (melanic) phenotype.
Which condition is required for natural selection to lead to evolution in a population?
Answer: There must be heritable variation and differential reproductive success
Natural selection requires heritable variation and differences in survival/reproduction so that favourable alleles increase in frequency over generations.
That was 6 of 36 Evolution and speciation questions.
Practise all 36 freeOutlineAO2 · 1–4 marks
A brief account or summary: the main points in two or three sentences, no evaluation.
DistinguishAO2 · 1–4 marks
Make the difference clear for BOTH terms — a definition of one of them is only half an answer.
DefineAO1 · 1–2 marks
Give the precise meaning — one sentence, the key terms in it, no example needed unless asked.
36 Evolution and speciation questions — free with an account. Spaced repetition, streaks and full exam simulations included.
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