Topic 5.1: Evidence for evolution

Question 1

Definition of evolution

Answer 1

Cumulative change in the heritable characteristics of a population

Question 2

Are these traits acquired over a lifetime?

Answer 2

They are heritable traits of alleles in an organism’s DNA

Question 3

Evidences for evolution

Answer 3

a) Fossil record
b) Selective breeding
c) Comparative anatomy

Question 4

Definition of fossil

Answer 4

Preserved remains or traces of a past organism

a) Direct - Body fossils
b) Indirect - Trace fossils

Question 5

Definition of fossil record

Answer 5

Sum of all discovered and undiscovered fossils and their relative placement in rock.

Question 6

How does the fossil record provide evidence for evolution? (Strength / Limitation)

Answer 6

a) It shows that changes have occurred in organisms, so these changes have occurred in a consistent sequence of development
b) Not all organisms are fossilized, so there are gaps in the fossil record.

Question 7

Definition of selective breeding

Answer 7

Process where humans breed animals or plants for particular traits

Question 8

How does selective breeding occur? (2)

Answer 8

a) Individuals which show the most desirable traits are chosen to breed together
b) The next generation will have an increased frequency of the desired trait

Question 9

How does selective breeding provide evidence for evolution? (Strength / Limitation)

Answer 9

a) Targeted breeds show significant variation in a relatively short period of time.
b) This does not prove that evolution of species have actually occurred naturally.

Question 10

Definition of homologous structures

Answer 10

Anatomical features that share a common basic structure despite having different functions.

Question 11

Definition of adaptive radiation

Answer 11

Process whereby several new species rapidly diversify from an ancestral source, with each new species adapted to utilize a specific unoccupied niche.

Question 12

How does comparison of homologous structures provide evidence for evolution?

Answer 12

a) Evolution of homologous structures by adaptive radiation explains similarities in structure when there are differences in function.
b) Organisms adapt to different niches

Question 13

Example of homologous structure (different appendages, same bone structure)

Answer 13

Pentadactyl limb

Question 14

How is the pentadactyl limb present and used in the following organisms?

a) Humans
b) Horse
c) Whale
d) Bird

Answer 14

a) Hands - Tool manipulation
b) Hooves - Galloping
c) Fins - Swimming
d) Wings - Flying

Question 15

Definition of speciation

Answer 15

Process by which two unrelated species diverge into separate species

Question 16

Process of speciation (2)

Answer 16

1) If two populations of the same species become geographically separated, they will experience different ecological conditions
2) Over time the two populations will adapt to different environmental conditions and gradually diverge from one another

Question 17

Factors that affect the degree of divergence of a species

Answer 17

a) Extent of geographical separation

b) Amount of time since separation occurred

Question 18

To what extent will speciation occur?

Answer 18

When the the members of the two populations cannot longer interbreed and produce fertile offspring.

Question 19

What are the forms of peppered moths?

Answer 19

a) Light coloration

b) Dark melanic

Question 20

What are the environment conditions in unpolluted and polluted areas?

Answer 20

a) Unpolluted: Trees are covered by a pale-colored lichen, providing camouflage for the lighter moth.
b) Polluted: SO2 kills the lichen while soot blacken the bark, providing camouflage for the dark moth.

Question 21

What is the frequency of the two forms of peppered moths on the environment?

Answer 21

a) In polluted environments, there is a higher frequency of light peppered moths
b) In unpolluted environments, there is a higher frequency of dark peppered moths.