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3.4.5 Species and taxonomy

AQA A-level Biology 3.4.5 practice on Species and taxonomy, with free MCQs, clues and worked explanations drawn from the Genetic information, variation and relationships between organisms section of specification 7402.

Specification route
3.4.5
Question bank
25 questions
Course stage
AS / Year 12

Sample questions

QUESTION 1 · 3.4.5 · LEVEL 1

What is the universally accepted biological definition of two organisms belonging to the same species?

  • They are able to interbreed to produce fertile offspring.
  • They share identical physical characteristics and habitats.
  • They have the exact same chromosome number and DNA sequence.
  • They occupy the same niche within a single ecosystem.
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A horse and a donkey can produce a mule, but a mule is sterile, so they are not the same species.

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Answer: They are able to interbreed to produce fertile offspring.

Two organisms belong to the same species if they are able to produce fertile offspring.

QUESTION 2 · 3.4.5 · LEVEL 2

What is the essential role of courtship behaviour in animal reproduction?

  • It is a necessary precursor to successful mating and aids in species recognition.
  • It actively triggers the random mutation of alleles to increase genetic diversity.
  • It prevents the independent segregation of homologous chromosomes.
  • It guarantees that offspring will be fertile by aligning chromosomes.
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Courtship ensures that individuals mate with members of their own species, avoiding wasted energy.

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Answer: It is a necessary precursor to successful mating and aids in species recognition.

Courtship behaviour as a necessary precursor to successful mating. The role of courtship in species recognition.

QUESTION 3 · 3.4.5 · LEVEL 2

A phylogenetic classification system attempts to arrange species into groups based on what criteria?

  • Their evolutionary origins and relationships.
  • Their physical similarities and anatomical features alone.
  • Their geographical location and habitat preferences.
  • Their current population size and species richness.
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Phylogeny looks at the evolutionary history and common ancestors.

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Answer: Their evolutionary origins and relationships.

A phylogenetic classification system attempts to arrange species into groups based on their evolutionary origins and relationships.

QUESTION 4 · 3.4.5 · LEVEL 2

Which statement correctly describes the hierarchy used in a phylogenetic classification system?

  • Smaller groups are placed within larger groups, with no overlap between groups.
  • Larger groups overlap to account for species that share characteristics of multiple taxa.
  • Species are arranged in a continuous spectrum based on their genetic diversity.
  • Groups are categorized chronologically based on when they evolved, allowing for extensive overlap.
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Think of a set of nested boxes; an item cannot be in two different small boxes at the same time.

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Answer: Smaller groups are placed within larger groups, with no overlap between groups.

It uses a hierarchy in which smaller groups are placed within larger groups, with no overlap between groups.

QUESTION 5 · 3.4.5 · LEVEL 1

In the standard taxonomic hierarchy, which list of taxa is in the correct order from largest to smallest?

  • Domain, kingdom, phylum, class, order, family, genus, species.
  • Kingdom, domain, class, phylum, family, order, genus, species.
  • Domain, kingdom, class, order, phylum, family, species, genus.
  • Phylum, kingdom, domain, order, class, genus, family, species.
Show clue

Use a mnemonic like 'Dear King Philip Came Over For Good Soup'.

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Answer: Domain, kingdom, phylum, class, order, family, genus, species.

One hierarchy comprises the taxa: domain, kingdom, phylum, class, order, family, genus and species.

QUESTION 6 · 3.4.5 · LEVEL 1

According to the binomial naming system, how is each species universally identified?

  • By a binomial consisting of the name of its genus and species.
  • By a binomial consisting of the name of its family and genus.
  • By its common name translated into Latin.
  • By its domain, kingdom, and specific identifying number.
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For example, *Homo sapiens*.

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Answer: By a binomial consisting of the name of its genus and species.

Each species is universally identified by a binomial consisting of the name of its genus and species.

QUESTION 7 · 3.4.5 · LEVEL 3

Why do closely related species often exhibit very similar courtship behaviours?

  • Courtship behaviours are genetically determined and have evolved from a common ancestor.
  • They learn the behaviours by observing other species in their shared habitat.
  • Courtship behaviours are identical across all members of a single Kingdom.
  • Similar environments cause unrelated species to spontaneously develop identical mating dances.
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Like physical traits, these actions are coded in the DNA inherited from evolutionary predecessors.

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Answer: Courtship behaviours are genetically determined and have evolved from a common ancestor.

The role of courtship in species recognition. Courtship is genetically determined; closely related species share recent common ancestors and thus share similar (though usually distinct enough to prevent interbreeding) genes for these behaviours.

QUESTION 8 · 3.4.5 · LEVEL 2

In the binomial naming system, the wolf is known as *Canis lupus* and the domestic dog is known as *Canis familiaris*. What does this indicate about their classification?

  • They belong to the same genus but are different species.
  • They belong to the same species but are from different genera.
  • They belong to the same family but have no other taxonomic connection.
  • They are identical species with different common names.
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The first word is the generic name, and the second is the specific name.

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Answer: They belong to the same genus but are different species.

Each species is universally identified by a binomial consisting of the name of its genus and species. Both share the genus *Canis*, but have different species names (*lupus* vs *familiaris*).

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