Species and Taxonomy: AQA A Level Biology Exam Questions by Topic

AQASpecies and TaxonomyExam Questions
Written by Tom Whitburn

Species and taxonomy (AQA 3.4.5) is a short section, but it turns up on both Year 12 and A-level papers, often as quick one- and two-mark parts that are easy to drop. You need to define a species by fertile offspring, explain why courtship is needed before mating and how it lets animals recognise their own species, describe a phylogenetic classification as a hierarchy of groups based on evolutionary relationships, list the taxa from domain to species, use binomial names, and appreciate how genome sequencing and immunology clarify how organisms are related.

The examiners' reports point to the same slips each year. Students leave 'fertile' out of the species definition, describe groups within groups without saying there's no overlap, spot a family on a diagram but don't write the word, say courtship songs are 'different' without giving the difference, and write about 'comparing DNA' or 'new technology' instead of base sequences.

Start with species and courtship, then the hierarchy and the taxa, then binomial names, and finish with how molecular evidence clarifies relationships. Answer each question on paper before you open the mark scheme. If you'd like help with this topic, my AQA masterclasses run online on Tuesdays at 5.15pm for Year 12 and on Wednesdays or Thursdays at 6.30pm for Year 13.

What you need from GCSE and Year 12

Each question on this page assumes you're secure on these GCSE and Year 12 ideas. If any of them feels shaky, revise it before you start.

  • GCSE: a species is a group of organisms that can breed together to produce fertile offspring.
  • GCSE: Linnaeus classified living things into kingdom, phylum, class, order, family, genus and species, and named each species with a binomial: genus then species.
  • GCSE: evolutionary trees show how closely related organisms are, and new evidence from chemical analysis changed how organisms are classified.
  • Year 12 (AQA 3.4.4): natural selection results in species that are better adapted to their environment, and adaptations may be behavioural.
  • Year 12 (AQA 3.4.1): a gene is a base sequence of DNA that codes for the amino acid sequence of a polypeptide or for a functional RNA, such as ribosomal RNA.

Key terms

These words come up in the questions and mark schemes. Examiners expect you to use them exactly.

  • Species: a group of organisms that are able to produce fertile offspring.
  • Courtship behaviour: behaviour that is a necessary precursor to successful mating; it lets individuals recognise members of their own species and stimulates mating.
  • Phylogenetic classification: arranging species into groups based on their evolutionary origins and relationships.
  • Hierarchy: smaller groups placed within larger groups, with no overlap between groups.
  • Taxon: each group in a classification hierarchy (plural taxa).
  • The taxa, in order: domain, kingdom, phylum, class, order, family, genus and species.
  • Genus: the taxon above species; its name is the first word of a binomial, and species in the same genus are closely related.
  • Binomial: the universal two-part name of a species: the genus name followed by the species name, eg Homo sapiens.
  • Common ancestor: the ancestral species from which two or more species evolved; more closely related species share a more recent common ancestor.
  • Genome sequencing: finding the base sequence of DNA; the more similar the base sequences, the more closely related the species.

What these questions cover (AQA 3.4.5)

The questions test these statements from the AQA AS and A-level Biology specification (7401/7402):

  • Species and courtship: Two organisms belong to the same species if they are able to produce fertile offspring. Courtship behaviour as a necessary precursor to successful mating. The role of courtship in species recognition.
  • Phylogenetic classification: A phylogenetic classification system attempts to arrange species into groups based on their evolutionary origins and relationships. It uses a hierarchy in which smaller groups are placed within larger groups, with no overlap between groups. Each group is called a taxon (plural taxa).
  • The taxa: One hierarchy comprises the taxa: domain, kingdom, phylum, class, order, family, genus and species.
  • Binomial names: Each species is universally identified by a binomial consisting of the name of its genus and species, eg, Homo sapiens.
  • Immunology and genome sequencing: Students should be able to appreciate that advances in immunology and genome sequencing help to clarify evolutionary relationships between organisms. (both questions here are about sequencing; none of the written questions available asks about immunological comparisons)

How to use this page

Write your answer on paper before you open the mark scheme. Allow about 1.3 minutes per mark: the 18 questions are worth 27 marks, so about 35 minutes in total. Then mark your answer strictly against the mark scheme and read the examiners' tip underneath it. If you'd rather print the questions, download the PDF pack.

Species and courtship (3.4.5)

Question 1

AS Paper 1 · June 2017 · Q09.1 · 2 marks

Define the terms species and species richness.

Question text: define each of the following terms: species; species richness, 2 marks.
Show the mark scheme Mark scheme: species, a group of organisms that are able to produce fertile offspring; species richness, the number of different species in a community. Accept habitat, ecosystem or area; reject population.

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From the examiners' report: Most defined a species, but 'can make offspring' isn't enough: it must be fertile offspring. Species richness is the number of species in a community, not a population.

Question 2

A level Paper 1 · June 2019 · Q07.3 · 2 marks

Suggest and explain why successful reproduction between two species of Ulva doesn't happen.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Earlier part of the same exam question, giving the information this part uses. Figure 6: diagram of the seaweed Ulva lactuca with its thallus and holdfast labelled. Figure 7: life cycle of U. lactuca, alternating between a diploid alga and a haploid alga via haploid mobile single cells and a diploid zygote. Question: U. prolifera also makes haploid mobile cells; explain why it can't reproduce successfully with U. lactuca, 2 marks.
Show the mark scheme Mark scheme: they are different species; so if the cells fused they would not produce fertile offspring, or they have characteristics that make them reproductively isolated, such as cells not fusing, being produced at different times, or geographical isolation.

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From the examiners' report: No examiners' report for this part. Say they are different species, then explain: even if the cells fused they wouldn't produce fertile offspring. A reason for reproductive isolation also scores.

Question 3

AS Paper 2 · June 2022 · Q08.1 · 1 mark · Medium

Suggest which type of guppy behaviour could be affected by brightly coloured stones in the tank.

Figure 9: mean number of spots per guppy rising over the generations in a tank containing brightly coloured stones. Question: the guppies weren't aggressive and their feeding didn't change; suggest one type of guppy behaviour the stones could affect, 1 mark.
Show the mark scheme Mark scheme: mating, courtship or sexual behaviour. Ignore breeding or reproduction.

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From the examiners' report: 50% said mating or courtship. Swimming, being happier or playful, or less aggressive didn't score; the stem has already ruled out aggression and feeding.

Question 4

A level Paper 2 · June 2017 · Q02.3 · 1 mark · Hard

Suggest why releasing radiation-sterilised male mosquitoes hasn't controlled dengue well.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Passage: dengue is caused by a virus carried by the mosquito Aedes aegypti; the Sterile Insect Technique releases large numbers of male A. aegypti made infertile by radiation. Question: suggest one reason why this hasn't been very successful, 1 mark.
Show the mark scheme Mark scheme: radiation affects the males' attractiveness, courtship, survival or life span. Accept die or less likely to survive due to radiation; accept disease transmitted by other means.

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From the examiners' report: Very few scored. Credited answers said the radiation shortened the males' lives or made them less attractive to females. 'Sterile mosquitoes still carry the virus' didn't score.

Question 5

AS Paper 1 · June 2018 · Q06.3 · 2 marks · Easy

Describe evidence from courtship song recordings that two fruit flies are closely related but different species.

Figure 6: recordings of the courtship songs of male D. erecta, male D. willistoni and female D. willistoni over the same time, each with a continuous sine song followed by a pulse song with louder peaks; the peaks differ in number and position between the two males.
Show the mark scheme Mark scheme: the sine song is very similar or the same length for both, so closely related; but the pulse songs have different peaks or pulses. Must give a difference, such as number, length, amplitude or interval.

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From the examiners' report: 85.8% scored at least 1. Use Figure 6: the sine songs are similar, then give an actual difference in the pulse song, such as the number of peaks, not just 'they're different'.

Question 6

AS Paper 1 · June 2018 · Q06.4 · 2 marks · Hard

Use the song recordings to suggest why two female fruit flies didn't attempt to mate.

Question text: with females as the visual stimulus, a male and female D. willistoni sang and then mated, but two female D. willistoni together did not attempt to mate; use Figure 6 to suggest why, 2 marks.
Show the mark scheme Mark scheme: the peaks in the pulse song occur at the same time, or the songs are identical, or male peaks are different; therefore no male song to stimulate or cause mating.

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From the examiners' report: Only 3.4% got both. Use Figure 6 to show the two female songs match, then say there's no male song to stimulate mating. 'The female knew it was another female' doesn't score.

Phylogenetic classification and taxa (3.4.5)

Question 7

AS Paper 2 · June 2022 · Q05.1 · 2 marks · Hard

Describe how organisms are grouped in a phylogenetic classification system.

Question text: describe how organisms are grouped in a phylogenetic classification system, 2 marks.
Show the mark scheme Mark scheme: a hierarchy with no overlaps, or smaller groups within larger groups with no overlaps; grouped according to evolutionary origins, relationships or history. Accept common ancestry.

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From the examiners' report: Just over 40% got 1 mark and only 5% got 2. Groups within groups isn't enough: say there's no overlap, and that grouping is by evolutionary relationships.

Question 8

AS Paper 1 · June 2018 · Q06.1 · 2 marks · Hard

Explain how a diagram of the classification of four fruit fly species shows a hierarchy.

Figure 5: nested ovals; Drosophilidae contains two ovals, Zaprionus (with neglectus and sexvittatus) and Drosophila (with erecta and willistoni). Question: explain how Figure 5 shows a hierarchy, 2 marks.
Show the mark scheme Mark scheme: smaller groups within larger groups, or larger groups containing smaller groups; with no overlap between groups.

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From the examiners' report: Just under 60% scored zero: students had either learned what a hierarchy is or they hadn't. Say smaller groups sit inside larger groups, with no overlap.

Question 9

AS Paper 1 · June 2018 · Q06.2 · 1 mark

Name the taxon to which Drosophilidae belongs.

Question text: name the taxon to which Drosophilidae belongs, using Figure 5, 1 mark.
Show the mark scheme Mark scheme: family. Accept phonetic spellings.

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From the examiners' report: About half got it. Many spotted the levels on the diagram but didn't turn them into a taxon name: the answer is family.

Question 10

AS Paper 2 · June 2022 · Q05.2 · 1 mark · Easy

Use a table of taxa to give the scientific name of a taxon labelled on a diagram of two rhinoceros species.

Table 1: taxa of a rhinoceros: class Mammalia, order Perissodactyla, family Rhinocerotidae, genus Rhinoceros, species unicornis. Figure 4: nested ovals; the outer oval B contains a middle oval, which contains the genera Rhinoceros (with unicornis) and Dicerorhinus (with sumatrensis).
Show the mark scheme Mark scheme: Perissodactyla. Accept incorrect spellings close to Perissodactyla; accept 'order'.

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From the examiners' report: 72% got it. Count outwards from the genus ovals: the next oval is the family, so B is the order, Perissodactyla.

Question 11

AS Paper 2 · June 2023 · Q09.4 · 2 marks · Easy

Complete a table of the phylogenetic classification of two fish species.

Table 6: classification of Opsanus tau and Trachurus trachurus with gaps to fill; given are Animalia, Chordata, class Actinopterygii, Batrachoidiformes and Carangiformes, family Batrachoididae and Carangidae, and species tau and trachurus.
Show the mark scheme Mark scheme: 1 mark for the first column: kingdom, phylum, order, genus; 1 mark for the second and third columns: Animalia, Chordata, Opsanus, Trachurus.

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From the examiners' report: About 50% got full marks. Learn the order of the taxa, and take the genus from the first word of each binomial: Opsanus and Trachurus.

Binomial names (3.4.5)

Question 12

AS Paper 2 · November 2021 · Q03.1 · 1 mark

Name the system of identifying an organism by its genus and species names.

Question text: in taxonomy an organism is identified by its species name and genus name; what term describes this method of naming organisms, 1 mark.
Show the mark scheme Mark scheme: binomial.

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From the examiners' report: No examiners' report for this part. The answer is binomial: the genus name followed by the species name, as in Homo sapiens.

Question 13

AS Paper 2 · November 2020 · Q01.3 · 1 mark

Name the taxa represented by Littorina and littorea.

Question text: name the taxon in the hierarchy of classification represented by 1, Littorina, and 2, littorea, 1 mark.
Show the mark scheme Mark scheme: Littorina, genus, and littorea, species. Accept phonetic spelling; accept genera.

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From the examiners' report: Most got this. In a binomial the first word is the genus and the second is the species; you need both for the mark.

Question 14

A level Paper 1 · June 2017 · Q08.3 · 1 mark

Name the taxon scientists disagree about when one snake is called Liasis papuana or Apodora papuana.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Figure 3: two classifications, X based on observable characteristics and Y on genetic comparisons, of three Python species: Liasis mackloti, Liasis olivaceus and Liasis papuana. Question: some scientists call one species Liasis papuana and others Apodora papuana; name the taxon they disagree about, 1 mark.
Show the mark scheme Mark scheme: genus or genera. Two answers score no mark.

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From the examiners' report: No examiners' report for this part. Only the first word of the binomial changes, so the disagreement is about the genus. Give one answer only: two answers score zero.

Question 15

A level Paper 1 · June 2018 · Q03.5 · 2 marks · Easy

Explain what the names of three bee species suggest about their evolutionary relationships.

Question text: three bee species from farmland were Peponapis pruinosa, Andrena chlorogaster and Andrena piperi; what do these names suggest about their evolutionary relationships, 2 marks.
Show the mark scheme Mark scheme: A. chlorogaster and A. piperi are more closely related to each other than to P. pruinosa, or share a more recent common ancestor; because they are in the same genus. Must be comparative.

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From the examiners' report: 62.1% scored. Make it comparative: the two Andrena species are more closely related because they share a genus. Don't say they're unrelated to P. pruinosa.

Question 16

A level Paper 3 · June 2025 · Q03.1 · 1 mark · Medium

Count the different genera of beetles named in a passage about tansy beetles.

Passage: the tansy beetle Chrysolina graminis lives on tansy, Tanacetum vulgare; two other green beetles share the habitat, the dock beetle Gastrophysa viridula and the mint leaf beetle Chrysolina herbacea. Figure 2: the beetle's yearly life cycle. Question: how many different genera of beetles are there, 1 mark.
Show the mark scheme Mark scheme: 2. If no number is given, accept Gastrophysa and Chrysolina.

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From the examiners' report: Just over half got it. Look at the first word of each beetle's binomial: the answer is 2. 3 is the number of beetle species, and 4 the number of all species.

Clarifying evolutionary relationships (3.4.5)

Question 17

AS Paper 2 · June 2024 · Q05.1 · 2 marks

Explain how analysing ribosomal RNA genes let scientists work out phylogenetic relationships between orchids.

Question text: orchids form a large family of flowering plants; scientists analysed genes coding for ribosomal RNA; explain how this analysis allowed them to determine phylogenetic relationships between orchid species, 2 marks.
Show the mark scheme Mark scheme: compare the DNA base or nucleotide sequence; the more similar the genes or DNA, the more closely related the species. Accept more recent common ancestor.

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From the examiners' report: Vague answers about 'comparing the DNA' or the 'genetic code' missed the first mark: compare base sequences. Then say more similar sequences mean more closely related species.

Question 18

A level Paper 1 · June 2023 · Q06.3 · 1 mark

Suggest why several bacterial species have been renamed in recent years.

Information from earlier in this question:

Earlier part of the same exam question, giving the information this part uses. Passage: in the early 20th century, bacteria were classified by the position, shape and number of flagella seen with an optical microscope; these features may be shared by species in a genus, and flagella are fragile and hard to stain. Question: suggest why several bacterial species have been renamed, 1 mark.
Show the mark scheme Mark scheme, one of: DNA, mRNA or RNA base sequencing; amino acid sequencing; electron microscopes with greater resolution; electron microscopes with improved staining or preparation. Accept genome sequencing.

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From the examiners' report: 'New technology' didn't score, and the bacteria hadn't evolved or mutated. Name a technique: DNA base sequencing, amino acid sequencing, or electron microscopes with greater resolution.

Where students lose marks (from AQA examiners' reports and mark schemes)

Each point below is followed by wording that gained marks.

  • Fertile offspring, not just offspring: Most students could define a species, but simpler answers just said organisms 'can make offspring'. In the same question, many gave species richness as the number of species in a population.

    ✔ Gains credit: "A group of organisms that are able to produce fertile offspring."

  • Groups within groups, with no overlap: On describing a phylogenetic classification, just over 40% got 1 mark and only 5% got 2; the common error was writing about groups within groups without the lack of overlap. On explaining the hierarchy in Figure 5, just under 60% scored zero.

    ✔ Gains credit: "Smaller groups within larger groups with no overlaps"; "grouped according to evolutionary origins / relationships".

  • Turn the letter into the taxon name: Only about half named the taxon Drosophilidae belongs to. Many identified the taxonomic groups using the letters f, g and s on the diagram, but didn't convert the 'f' into family.

    ✔ Gains credit: "Family."

  • Courtship stimulates mating: Only 3.4% scored both marks on why two female fruit flies didn't attempt to mate. Few used Figure 6 or understood that courtship is a behaviour that stimulates mating; most said the female 'knew' it was another female.

    ✔ Gains credit: "The peaks in the songs are identical (both female)"; "so there is no male song to stimulate mating".

  • Name a difference you can see in the song: 85.8% scored at least 1 mark on the fruit fly songs. Marks were lost by not using Figure 6, by saying the songs were different without giving a difference, and by confusing frequency with amplitude.

    ✔ Gains credit: "The sine songs are very similar"; "but the pulse songs have different peaks (number, length, amplitude or interval)".

  • Compare base sequences, not 'the DNA': On the orchid ribosomal RNA genes question, too many missed the first mark with vague references to 'comparing the DNA' or the 'genetic code', and then missed the second by only writing about comparing the DNA.

    ✔ Gains credit: "Compare the DNA base / nucleotide sequence"; "the more similar the DNA, the more closely related the species".

  • Name the technique, not 'new technology': On why bacteria have been renamed, many answers said only 'new technology' or 'scientists are better at classification', or thought the bacteria had evolved or mutated. Some left 'base' out of DNA sequencing, or named a microscope without its resolution.

    ✔ Gains credit: "DNA / RNA base sequencing", "amino acid sequencing" or "electron microscopes with greater resolution".

  • Count genera, not species: Just over half got the number of beetle genera right. The common wrong answers were 3, the number of beetle species, and 4, the number of all the species in the information.

    ✔ Gains credit: "2" (Gastrophysa and Chrysolina).

Download the questions

Download the PDF pack (18 questions, mark schemes at the end)

Keep practising

Questions, mark schemes and examiners' report extracts © AQA.

Tom Whitburn
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