36 exam-style questions on Diversity of organisms — topic A3.1 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.
Define the biological species concept by selecting the correct statement.
Answer: Organisms that interbreed to produce fertile offspring
The biological species concept defines a species as a group whose members can interbreed and produce fertile offspring, so they share a gene pool.
State the correct sequence of the taxonomic hierarchy from broadest to most specific.
Answer: Domain → kingdom → phylum → class → order → family → genus → species
The Linnaean hierarchy runs domain, kingdom, phylum, class, order, family, genus, species from most inclusive to least inclusive.
In the binomial name Homo sapiens, determine what the word sapiens represents.
Answer: The specific epithet
In binomial nomenclature the first word is the genus (Homo, capitalised) and the second is the specific epithet identifying the species (sapiens, lower case).
Identify the three domains into which all cellular organisms are currently classified.
Answer: Bacteria, Archaea, Eukarya
The three-domain system based on ribosomal RNA sequences recognises Bacteria, Archaea and Eukarya as the highest-ranking groups.
Suggest the best reason why natural classification should be based on shared evolutionary ancestry rather than on overall physical similarity.
Answer: Convergent evolution can make appearance misleading
Convergent evolution produces analogous features in unrelated organisms, so classification by ancestry (using shared derived traits and molecular data) better reflects true relationships.
That was 6 of 36 Diversity of organisms questions.
Practise all 36 freeStateAO1 · 1–2 marks
One word or one short sentence. No explanation, no working: the mark is for the fact itself.
DefineAO1 · 1–2 marks
Give the precise meaning — one sentence, the key terms in it, no example needed unless asked.
SuggestAO3 · 3–8 marks
Propose a plausible solution, hypothesis or answer; there may be no single right one, but it must be reasoned.
36 Diversity of organisms questions — free with an account. Spaced repetition, streaks and full exam simulations included.
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