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CAIE A-Level Biology A2 18.1 Classification Questions

Practise classification questions by applying species concepts, comparing domains and kingdoms, and completing taxonomic ranks from organism evidence.

Syllabus
2028–2030
Course
Biology 9700
Level
A2

Exam points

  • apply biological, morphological or ecological species concepts to organism evidence
  • compare Archaea, Bacteria and Eukarya using rRNA, membrane lipids and cell walls
  • complete taxonomic ranks or kingdom features for animals, plants, fungi and protoctists

Covered syllabus points

18.1.1—Species concepts18.1.2—Three domains18.1.3—Archaea and Bacteria as prokaryotes18.1.4—Eukarya domain taxonomic hierarchy18.1.5—Characteristic features of kingdoms18.1.6—Virus classification

Question 1

[Maximum number: 3]

The sea blush, Plectritis congesta, is a flowering plant that grows on the west coast of North America.

Individual sea blush plants produce fruit that is either winged or wingless. Investigations have shown that this characteristic is controlled by a single gene with two alleles:
- a dominant winged fruit allele
- a recessive wingless fruit allele.

Fig. 3.1 shows the difference in structure between winged fruit and wingless fruit phenotypes.

Fig. 3.1

Fig. 3.1

Early taxonomists classified sea blush plants with winged fruits as a different species to sea blush plants with wingless fruits.

Since this time, evidence from observations and experiments has confirmed that the plants belong to the same species.

Suggest three examples of the evidence obtained that helped to confirm that these sea blush plants belong to the same species.

Question 2

[Maximum number: 1]

The aye-aye, Daubentonia madagascariensis, is a mammal, native to Madagascar. Aye-ayes are active at night and make their nests high up in trees. They feed on insect larvae in the trunks of trees.

Fig. 1.1 shows an aye-aye.

Fig. 1.1

Fig. 1.1

The International Union for Conservation of Nature (IUCN) categorises the aye-aye as endangered. This means that the aye-aye has a very high risk of becoming extinct in the wild.

Name the domain to which the aye-aye belongs.

Question 3

[Maximum number: 8]

Question (a)

(a)

Most organisms are classified according to a taxonomic hierarchy.
The hierarchy is shown in Fig. 8.1 but the group names are not in the correct order.
1 - kingdom
2 - order

3 -genus
4 - family
5 - domain

6 - class

7 - species
8 - phylum
Fig. 8.1
Complete Table 8.1 by writing the numbers in the correct order.

Table 8.1

Table 8.1

[ 2 ]

Question (b)

(b)

Members of the Eukarya domain share similar features but will also have several differences.

Complete Table 8.2 by stating the differences between the kingdoms Fungi and Plantae.

Table 8.2

Table 8.2

[ 3 ]

Question (c)

(c)

Name the domain that contains organisms with a peptidoglycan cell wall.

[ 1 ]

Question (d)

(d)

Viruses are not included in the three domain classification.
Outline how viruses are classified.

[ 2 ]
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