Evolution

Question 1

Explain ecological isolation as a reproductive isolating mechanism.

Answer 1

Organisms live in different habitats within a region.

Question 2

Explain mechanical isolation as a reproductive isolating mechanism.

Answer 2

Organisms have differences in morphological features, such as genitalia unsuitable for one another.

Question 3

Describe and give an example of adaptive radiation.

Answer 3

Adaptive radiation is the relatively rapid evolution of a single species into many species, filling a variety of formerly empty ecological niches. ie. Darwin’s finches

Question 4

List the five types of prezygotic reproductive isolating mechanisms.

Answer 4

Ecological isolation, behavioural isolation, temporal isolation, mechanical isolation, and gametic isolation.

Question 5

Describe convergent evolution.

Answer 5

The evolution of similar traits in unrelated species that occupy similar environments in different areas in the world.

Question 6

Describe sympatric speciation.

Answer 6

The evolution of populations within the same geographic area into separate species.

Question 7

Describe allopatric speciation.

Answer 7

The formation of a new species as a result of evolutionary changes following a period of genetic isolation.

Question 8

Explain zygote mortality as a reproductive isolating mechanism.

Answer 8

The zygote produced is unable to survive.

Question 9

Describe and give an example of divergent evolution.

Answer 9

Divergent evolution is large-scale evolution of a group into many different forms, adaptive radiation on a larger scale. ie. homologous structures

Question 10

Name the four main types of natural selection.

Answer 10

Directional selection, stabilizing selection, disruptive selection, and sexual selection.

Question 11

What is the founder effect?

Answer 11

Genetic drift that occurs when a small number of individuals separate from their original population to start a new population.

Question 12

What are vestigial features?

Answer 12

Structures that serve no useful function but are homologous with larger, useful structures found in other living organisms or ancestral forms. ie. appendix, and goosebumps.

Question 13

Explain hybrid infertility as a reproductive isolating technique.

Answer 13

Offspring survive, but are sterile and cannot reproduce.

Question 14

What is a genetic bottleneck?

Answer 14

A dramatic, often temporary, reduction in population size.

Question 15

Genetic drift can occur from which two things?

Answer 15

Genetic bottleneck and founder effect.

Question 16

Explain hybrid inviability as a reproductive isolating technique.

Answer 16

The offspring develops, but dies before birth or before it reaches maturity.

Question 17

Describe sexual selection.

Answer 17

It favours the selection of traits that influence mating success.

Question 18

Name the two main categories of reproductive isolating mechanisms.

Answer 18

Prezygotic and post zygotic.

Question 19

Explain temporal isolation as a reproductive isolating mechanism.

Answer 19

Organisms breed at different times of the year.

Question 20

List the three types of post zygotic reproductive isolating mechanisms.

Answer 20

Zygote mortality, hybrid inviability, and hybrid infertility.

Question 21

What are analogous features?

Answer 21

Structures that perform the same function as another, but are not similar in origin. ie. bird and insect wings.

Question 22

Explain reproductive isolating mechanisms.

Answer 22

Any behavioural, structural, or biochemical factor that prevents individuals of different species from successfully reproducing.

Question 23

Define biogeography.

Answer 23

The scientific study of the geographic distribution of organisms on both living species and fossils.

Question 24

Describe disruptive selection.

Answer 24

The environment favours two or more variations at opposite extremes from the population average.

Question 25

Describe stabilizing selection.

Answer 25

One species becomes well adapted to their environment, and selection pressures keep them from changing.

Question 26

Explain natural selection.

Answer 26

Natural selection is the way in which nature favours the reproductive success of some individuals over others in a population.

Question 27

What is genetic drift?

Answer 27

Changes to allele frequency as a result of chance, which have a larger effect on a smaller population.

Question 28

Describe coevolution.

Answer 28

One species evolves in response to the evolution of another species.

Question 29

Define macroevolution.

Answer 29

Changes in allele frequencies and phenotypic traits within a population and species.

Question 30

Explain gametic isolation as a reproductive isolating mechanism.

Answer 30

Sperm cannot reach or fertilize the egg.

Question 31

Explain behavioural isolation as a reproductive isolating mechanism.

Answer 31

Organisms use different courtship/mating clues to attract mates.

Question 32

What are homologous features?

Answer 32

Structures similar in anatomy, but differ in function. Organisms that have structural similarities may have evolved from a common ancestor. ie. the forelimbs of humans, cats, whales, and bats.

Question 33

Describe directional selection.

Answer 33

It occurs when the environment favours individuals with more extreme variations of a trait than the population average.