natural selection and genetic modification sample exam questions and answers

Question 1

Which naturalist worked alongside Darwin and is famous for his work on speciation?

Answer 1

wallace

Question 2

What is MRSA?

Answer 2

Antibiotic-resistant bacteria

Question 3

What name was given to the human-like skeleton that walked upright but had a small skull?

Answer 3

Lucy

Question 4

Which of these is a domain in the three-domain system developed by Woese?

Answer 4

Archaea

Question 5

Describe why Darwin was reluctant to publish his findings when he returned from his voyage to the Galapagos Islands. [2 marks]

Answer 5

Answer (two from):

• his idea challenged that of the Church
• the Church was very powerful at the time
• he did not want to challenge God

Question 6

What does natural selection mean? [2 marks]

Answer 6

• the best adapted organisms in a population are most likely to survive
• and reproduce

Question 7

What are fossils? [2 marks]

Answer 7

• they are the imprints or remains of organisms

- which were alive millions of years ago

Question 8

Describe how the binomial system is used to name organisms. [2 marks]

Answer 8

Answer (two from):

• a two part name is given to every organism
• the first part of the name is the organism’s genus
• it may share this with other very closely related species
• the second part is the organism’s species
• this is unique to it

Question 9

Explain why there are gaps in the fossil record. [3 marks]

Answer 9

• not all fossils have been found yet
• not all parts of organisms become fossils
• some fossils have been destroyed in the rock cycle

Question 10

Explain how the changes in horse’s feet are evidence for evolution. [4 marks]

Answer 10

• the ground horses walked on was originally marshy
• smaller horses with bigger feet had the evolutionary advantage because they did not sink into the marshy ground
• the ground slowly dried up
• horses with smaller feet now had the evolutionary advantage because they could run away faster from predators

Question 11

Describe the evidence for human evolution. [6 marks]

Answer 11

• stone tools show increasing sophistication
• these began with simple hand axes (or other suitable example)
• then arrowheads and needle bones (or other suitable examples)
• many vertebrates including humans have the pentadactyl limb
• this suggests we evolved from a common ancestor
• Ardi is a female human-like fossilised skeleton that dates from 4.4 million years ago
• Ardi’s feet suggest that humans and chimpanzees evolved separately
• Lucy is a female human-like fossilised skeleton, and dates from 3.2 million years ago
• Lucy’s bones suggest that she walked in an upright position, like a human, but possessed a relatively small ape-like skull

Question 12

Describe how vertebrates are classified in the Linnaean system of classification. [6 marks]

Answer 12

• vertebrates are classified into five groups, each with different characteristics.
• mammals are warm-blooded, have hair or fur and breathe with lungs (or other suitable example)
• reptiles are cold-blooded, have dry scales and lay leathery eggs (or other suitable example)
• amphibians are cold-blooded, lay eggs and have soft permeable skin (or other suitable example)
• birds are warm blooded, have feathers and a beak and many can fly (or other suitable example)
• fish are cold-blooded, breathe through gills and lay many eggs (or other suitable example)

Question 13

Describe how the pentadactyl limb provides evidence for evolution. Give two examples in your answer and for each explain how their limbs are adapted to their function. [6 marks]

Answer 13

• many vertebrates including humans have the pentadactyl limb
• this is a five fingered limb structure
• this suggests they evolved from a common ancestor
• the bat has evolved a very long and thin pentadactyl limb with skin that has stretched across it to form wings (or other suitable example and adaptation for two marks)
• the whale has evolved a shorter pentadactyl limb within a flipper that allows it to swim (or other suitable example and adaptation for two marks)

Question 14

Doctors are now prescribing fewer antibiotics to reduce the evolution of antibiotic resistant bacteria. Describe the process of evolution of antibiotic bacteria. [5 marks]

Answer 14

Answer (five from):

• in every population there is variation, so some bacteria are resistant whilst others aren’t.
• the individuals (in this example, the bacteria) with the most advantageous characteristics are more likely to survive and reproduce
• so those that have the gene for resistance have an advantage
• this is survival of the fittest
• because of inheritance, the offspring of those with the advantageous characteristic are more likely to have it
• this process is repeated over many generations until a new species is produced

Question 15

How is natural selection different from selective breeding? [5 marks]

Answer 15

Answer (five from):

• Natural selection occurs when the best adapted organisms in a population are most likely to survive [1 mark] and reproduce
• the offspring of these organisms are likely these adaptations
• this will lead to evolution
• all organisms are evolving [1 mark] - award a mark for any named example
• selective breeding is artificial selection
• this occurs when people specifically choose organisms to reproduce because of desirable characteristics
• the offspring of these organisms are likely to have these characteristics
• cows, dogs and crop plants have been selectively bred/any named example

Question 16

Describe how DNA analysis has helped the process of classification. [4 marks]

Answer 16

Answer (four from):

• classification was originally based on the way different species looked
• DNA analysis involves mapping the genomes of organisms
• this is the sequence of DNA base pairs that make up an organism
• comparisons between genomes of organisms in different species lets scientists see how close they are genetically
• this is a more accurate way of classifying organisms than the way they look
• many scientists now believe in three domains not five kingdoms