Speciation and Macroevolution

Question 1

Define Allopatric Speciation

Answer 1

Occurs when two populations of the same species become isolated from each other due to a geographic barrier.

Question 2

Define Parapatric Speciation

Answer 2

Occurs when 2 subpopulations evolve reproductive isolation

Question 3

Define Sympatric Speciation

Answer 3

Occurs when populations of species become reproductively isolated even though they share the same habitat

Question 4

What are the four pathways evolution can take?

Answer 4

1. Divergent evolution
2. Parallel evolution
3. Coevolution
4. Convergent evolution

Question 5

Divergent evolution definition

Answer 5

When a population of interbreeding organisms diverges (separates) into two or more descendent species. These organism share a common ancestor, but they adapt different traits.

Question 6

State 2 factors that influence divergent evolution.

Answer 6

1. Competition for resources
2. The availability of new niches

Question 7

Define Parallel evolution

Answer 7

When two species that once shared a common ancestor are exposed to similar environmental pressures despite their geographical isolation. Consequently, similar phenotypic traits are exhibited.

Question 8

Define convergent evolution

Answer 8

Where different species demonstrate similar adaptations to similar ecological niches in different locations, however do not share a close ancestral relationship.

Question 9

Define coevolution

Answer 9

The influence of closely associated species on each other in their evolution. These two species are reliant on each other.

Question 10

Examples of Coevolution relationships:

Answer 10

Predator prey, plant pollinator, host-parasite.

Question 11

What is a clinal variation?

Answer 11

Gradual changes or differences in inherited characteristics of adjoining species populations spread across a range of environments.

Question 12

Examples of clinal variations [list 3]

Answer 12

population differences along the side of a mountain, altitude, temperature differences.

Question 13

Define cline

Answer 13

a specific characteristic such as colour or size that may be measured in a gradient within a species

Question 14

What are geographical isolates?

Answer 14

Different populations prevented from breeding with each other by a permanent physical (extrinsic) barrier

Question 15

List 3 examples of geographical isolates

Answer 15

1. “True islands”
2. Ponds, lakes and oceans
3. Habitat fragmentation

Question 16

List 3 consequences of geographical isolation

Answer 16

Development of a new species, extinction, contact of main body of species.

Question 17

Explain Zone or belt of hybridisation

Answer 17

An area in which two divergent subspecies may interbreed.

Question 18

What is a subspecies?

Answer 18

Groups of natural populations within a species that differ genetically and are partly isolated from each other reproductively by having different ranges.