Classification and phylogenyAQA A-Level Biology: Subtopic test

1. 1
   A zoologist is classifying big cats. She records the lion as Panthera leo, the tiger as Panthera tigris and the domestic cat as Felis catus. Each of these three species has been placed in a hierarchy of taxa.

   (a)

   Which statement about the names of the three cats is correct?

   [1 mark]

   • APanthera is the species name of the lion and the tiger
   • BLeo and tigris are the genus names of the lion and the tiger
   • CFelis catus shows that the domestic cat is in the same genus as the lion
   • DThe lion and tiger are in the same genus, but the domestic cat is in a different genus

   (b)

   Which list gives the taxa in the hierarchy in order from largest to smallest?

   [1 mark]

   • AKingdom, domain, phylum, class, order, family, genus, species
   • BDomain, kingdom, phylum, class, order, family, genus, species
   • CDomain, kingdom, class, phylum, order, family, genus, species
   • DDomain, kingdom, phylum, class, family, order, genus, species

   (c)

   Suggest what the classification tells you about the evolutionary relationships between the lion, the tiger and the domestic cat.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A zoologist is cataloguing mammals from several countries. The common names of the same animal differ between languages. For example, the grey wolf is called 'wolf' in English, 'Wolf' in German and 'loup' in French, but all scientists refer to it as Canis lupus.

   (a)

   Which is the correct way to write the binomial for humans?

   [1 mark]

   • Ahomo sapiens
   • BHomo Sapiens
   • CHomo sapiens
   • DSapiens homo

   (b)

   What is the main advantage of using the binomial Canis lupus?

   [1 mark]

   • AScientists in every country can identify the same species
   • BIt describes the habitat of the species
   • CIt shows how many chromosomes the species has
   • DIt shows the species is a mammal

   (c)

   State the genus and the species of the grey wolf, and explain why a species cannot be placed in two different genera in the hierarchy.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Three species of beetle, P, Q and R, are placed in a phylogenetic classification. P and Q are in the same family but in different genera. R is in the same order as P and Q, but in a different family. A fourth species, S, is placed in the same genus as P.

   (a)

   Of the three species P, Q and R only, use the information to deduce which two are the most closely related and which is the least closely related to the other two, and explain your answer.

   [3 marks]

   (b)

   Explain why species S is more closely related to species P than species Q is to species P.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Four species of mammal, A, B, C and D, were compared. One gene was sequenced in each, and the base sequences of B, C and D were compared with that of A. The sequence of B was 98% identical to A, that of C was 91% identical and that of D was 76% identical. Antibodies were also made against the blood protein albumin from species A. The strength of the antibody reaction with albumin from each species was scored, with species A scoring 100: B scored 95, C scored 80 and D scored 35.

   (a)

   Explain how advances in genome sequencing and in immunology help to clarify evolutionary relationships between organisms.

   [6 marks]

   (b)

   Use the data to evaluate which species is most closely related to species A and which is least closely related. Comment on how confident you can be.

   [6 marks]

   Total for question 4: 12 marks

End of questions