Macroevolution: speciation

Question 1

What are the 4 species concepts?

Answer 1

1. Ecological
2. Phylogenetic
3. Phenetic
4. Biological

Question 2

Define the ecological species concept.

Answer 2

Individuals that share a niche :use the same resources and occupy the same space

Question 3

Define the phylogenetic species concept.

Answer 3

Members of the same species share a common ancestor

common ancestry provides genetic similarities

Question 4

Define the phenetic species concept.

Answer 4

Group of similar individuals – compare morphology, genetics, biochemistry, molecular genetics

Question 5

Define the biological species concept.

Answer 5

Members of a population that share the same gene pool

-Have the potential to interbreed and produce fertile offspring

Question 6

Name the limits of the phylogenetic concept.

Answer 6

Not all genes are useful for comparison

Question 7

Name the limits of the phenetic concept.

Answer 7

• Members of the same species can appear different

- Different species can look alike

Question 8

Name the limits of the biological concept.

Answer 8

• Not useful for asexually-reproducing species
• Can’t be applied to extinct species
• Can’t be applied to geographically isolated species

Question 9

Describe the general process of speciation.

Answer 9

a. Something prevents gene flow between populations
b. Populations accumulate genetic differences
c. Selection for increased reproductive isolation
d. Reproductive isolation develops

Question 10

What are the types of speciation?

Answer 10

Allopatric, sympatric, chromosome

Question 11

Define allopatric speciation.

Answer 11

A geographic barrier blocks gene flow and populations accumulate differences = selection pushes for reproductive isolation

Question 12

What are the favoring conditions for allopatric speciation?

Answer 12

• small population
• genetic drift
• new environment

Question 13

Define sympatric speciation.

Answer 13

Reproductive isolation between species in same geographic area, individuals in small area have different selection pressures= sub-population linked to specific resource + assortative mating

Then isolation pushes for reproductive isolation

Question 14

What is chromosome speciation and what are the 2 types?

Answer 14

Chromosome changes block gene flow

1. Autopolyploidy
2. Allopolyploidy

Question 15

Explain autopolyploidy.

Answer 15

2n doubles chromosome # and becomes 4n (2nx2)

• The 4n is no longer able to breed with 2n (4n x 2n = 3n sterile)
• 4n is reproductively isolated = new species

Question 16

Explain allopolyploidy.

Answer 16

2 different species combine to for polyploidy hybrid (2n x 2) but 2n are 2 diff species.