5.1 Evolution

Question 1

Define evolution.

Answer 1

The cumulative change in the heritable characteristic of a population.

Question 2

What is evolution a change in?

Answer 2

The allele frequency of a population’s gene pool over successive generations.

Question 3

Summarize Lamarck’s proposal.

Answer 3

He proposed that species change via habitual use and disuse.

Question 4

Name 3 of Lamarck’s key points in his theory (using a giraffe as an example)

Answer 4

1. A giraffe stretches it’s neck to reach leaves in tall trees
2. The neck becomes extended from constant use
3. The giraffe’s offspring inherit it’s long neck

Question 5

Why was Lamarck’s proposal rejected?

Answer 5

The acquired traits do not have a genetic basis, and therefore cannot be inherited.

Question 6

Summarize Darwin and Wallace’s proposal.

Answer 6

They proposed that species change via natural selection.

Question 7

Name 3 of Darwin and Wallace’s key points in his theory (using a giraffe as an example)

Answer 7

1. A giraffe with a longer neck can reach leaves in tall trees
2. The giraffe will get enough food to survive and reproduce
3. The giraffe has more offspring

Question 8

Name the 3 main mechanisms of change

Answer 8

1. Mutations
2. Sexual reproduction
3. Gene flow

Question 9

Define mutation as a mechanism of change.

Answer 9

Changes to a/the gene sequence.

Question 10

Define sexual reproduction as a mechanism of change.

Answer 10

Creates new gene combinations.

Question 11

Define gene flow as a mechanism of change.

Answer 11

Describes immigration and emigration.

Question 12

Name the two mechanisms by which population variety can be altered.

Answer 12

1. Random chance (genetic drift)

2. Directed intervention (natural or artificial selection)

Question 13

Fill in the blank. The impact of a change is greater if the population is _____.

Answer 13

Small

Question 14

What may happen when populations become isolated?

Answer 14

The level of genetic divergence gradually increases the longer the populations remain separated.

Question 15

When will speciation occur?

Answer 15

When populations diverge to the extent that they can no longer interbreed and produce fertile, viable offspring.

Question 16

Define fossil.

Answer 16

The preserved remain or trace of a past organism.

Question 17

What is the totality of all fossils called?

Answer 17

The fossil record.

Question 18

What does the fossil record show?

Answer 18

That changes have occurred in organisms and that these changes have occurred in a consistent sequence of development.

Question 19

What do transitional fossils represent?

Answer 19

Intermediary forms within the evolution of a genus and demonstrate species connections.

Question 20

Define selective breeding.

Answer 20

A process which involves the mating of animals with desired characteristics (a form of artificial selection)

Question 21

Name 2 examples of selective breeding.

Answer 21

1. Draft horses (breeded for power), VS racing horses (breeding for speed)
2. Large variation in types of dog breeds.

Question 22

Name a process which results in adaptive radiation.

Answer 22

The rapid diversification of an anatomical feature.

Question 23

Simply define adaptive radiation.

Answer 23

Organisms adapting to different niches.

Question 24

Name a prime example of a homologous structure.

Answer 24

The pentadactyl limb.

Question 25

What does the comparison of embryonic development in animals demonstrate?

Answer 25

It demonstrates similarities which suggest a common evolutionary pathway.

Question 26

What structures do some species show the prescence of?

Answer 26

Functionless or reduced remnants of organs which were once present in ancestors.

Question 27

Define biogeography.

Answer 27

The distribution of species across an area.

Question 28

What can explain exceptions in biogeography?

Answer 28

Continental drift.