Classification and biodiversity

Question 1

Distinguish between homologous and analogous structures and explain why analogous features are no considered evidence of common ancestry (3)

Answer 1

• analogous structures are different structures to perform a similar function
• homologous structures similar structure performing different functions
• analogous structures arise through convergent evolution

Question 2

State the diagram usually shown to show common ancestry (1)

Answer 2

phylogenetic tree

Question 3

Modern taxonomic classification combine cetacea and artiodactyle into a single order. Explain how this illustrates the tentative nature of biological classification (2)

Answer 3

• classification may change
• a more information becomes available

Question 4

State the environmentaal factor most likely to explain the distribtuion in marine mammal species (1)

Answer 4

temperature

Question 5

Explain why a curve shows bimodial distribution (1)

Answer 5

two peaks

Question 6

Describe a disease caused by prokaryota, protoctista and fungi (3)

Answer 6

• pokaryota - salmonella
• protoctista - malaria
• fungi - athletes foot/ringworm/thrush

Question 7

What is the term used to describe the variation in number of species in different places (1)

Answer 7

biodiversity

Question 8

Identify two habitats where you would expect to find a high number of species (2)

Answer 8

• rain forest
• coral reef

Question 9

Suggest why there is a decrease in number of species of thi type of butterfly in region covered by sahara deserts (2)

Answer 9

• very little water
• a low vareity of food

Question 10

State why these two human forms might be classified as seperate species despite having many common features (2)

Answer 10

• not able to interbreed
• to produce fertile offspring

Question 11

Name a biological technique to prove that two species are different (1)

Answer 11

• DNA hybridisation
• genetic or DNA fingerprinting
• electrophoresis

Question 12

State one characteristic common to all vertebrates (1)

Answer 12

• possess a backbone / spine / internal skeleton / brain with cranium

Question 13

Explain how result of DNA profiling tests could have been used to determine that these two species were closely related (1)

Answer 13

• they would have more bands in common compared to other species

Question 14

Define the term species (2)

Answer 14

• a group of organisms that can interbreed
• produce fertile offspring

Question 15

Decribe two major features of eukaryote which would allow you to distinguish from a prokaryote (1)

Answer 15

• have nucleus
• membrane bound organelle
• 80s riboome
• DNA associated in chromosomes