Chapter 14: Speciation and Macroevolution

Question 1

What is speciation?

Answer 1

The evolution of one or more new species from an ancestral species

Question 2

What are the three broad processes that work together in the evolution of diversity?

Answer 2

• Natural selection cause populations to change over time as their gene pools accumulate small changes in response (microevolution
• Eventually a population accumulates so many changes that a new species can be identified
• Sometimes a rapid series of speciation events lead to the development of a collection of new species, genera, families, or higher classification groups (macroevolution)

Question 3

What are the different mechanisms of isolation?

Answer 3

Geograhpic, reproductive, spatial, and temporal

Question 4

What is reproductive isolation?

Answer 4

The separation of populations that are unable to interbreed because of changes that produce physical, biological or behavioural barriers

Question 5

What are pre-reproductive isolating mechanism?

Answer 5

A mechanism that prevents organisms from being able to interact to reproduce

Question 6

What are some pre-reproductive mechanisms?

Answer 6

-Geographical, temporal, behavioural and morphological mechanisms

Question 7

How can mechanisms of isolation impact gene flow?

Answer 7

Refer to figure 14.2.1 pg 260 for diagram

Question 8

What are post-reproductive isolation mechanisms?

Answer 8

A mechanism that prevents fertilisation occurring or an embryo developing into viable offspring if fertilisation does occur

Question 9

What are some examples of post-reproductive isolating mechanisms?

Answer 9

• Gamete mortality
• Zygote mortality
• Hybrid sterility

Question 10

What is allopatric speciation?

Answer 10

The speciation that is due to physical or geographic isolation

Question 11

What is geographic isolation?

Answer 11

When populations of the same species are separated by a type of physical barrier

Question 12

How can allopatric speciation occur?

Answer 12

Water (for terrestrial organisms), land (for aquatic organisms), mountains, continental drift, rising sea levels, and climate change

Question 13

What is sympatric speciation?

Answer 13

The speciation that occurs without physical or geographic isolation

Question 14

What is parapatric speciation?

Answer 14

The speciation that occurs when populations are separated by an extreme change in habitat; populations may interbreed in bordering areas

Question 15

What are the four types of diversification between species?

Answer 15

Divergent, convergent, parallel and co-evolution (refer to figure 14.4.1 pg 266 for diagram)

Question 16

What is divergent evolution?

Answer 16

A process whereby related species evolve new traits over time, away from the common ancestor, to give rise to new species

Question 17

What is covergent evolution?

Answer 17

A process whereby unrelated organsims evolve similar adaptations in response to similar environmental pressures

Question 18

What is parallel evolution?

Answer 18

A process whereby unrelated organsims eveolve similar adaptations in response to the same environmental pressures

Question 19

What is co-evolution?

Answer 19

A process whereby an evolutionary change in one species influences the evolution of another species

Question 20

Why do populations with reduced genetic diversity face an icreased risk of extinction?

Answer 20

• Small populations
• Catastrophic events
• Bottleneck effects reduce alleles present in a population
• Inbreeding
• Natural selection