3.1 Classification (Mark scheme points only)

Question 1

Which taxa has greatest variety of organisms

Answer 1

Kingdom

Question 2

Closely related genera are grouped together in a ?

Answer 2

Family

Question 3

Explain the evidence that lead to the three-domain system replacing the 5 kingdom model? (3)

Answer 3

• Scientists used methods of molecular phylogeny such as protein biochemistry
• Which found similarities and differences between archaea and bacteria
• Such as membrane structure and membrane bound organelles

Question 4

Give three methods scientists can used to share their findings amongst other scientists in the community

Answer 4

• Scientific conferences
• Peer reviewed journals
• Scientific journals

Question 5

Describe the information scientists can use to classify an organism as a new species (4)

Answer 5

• Compare morphology or physical characteristics
• Observe behaviour
• Use methods of molecular phylogeny such as GE, DNA profiling or bio informatics
• If they are unable to breed with other species and produce fertile offspring.

Question 6

Why may it be difficult to classify a newly discovered organism as a separate species

Answer 6

• Species are evolving over time
• There is variation within species such as sexual dimorphism