Species and Speciation

Question 1

What is the morphological species concept?

Answer 1

A species is a collection of individuals with similar morphology. If plotted on a graph, the species will cluster

Question 2

What are the advantages and disadvantages of the morphological species concept?

Answer 2

\+ = Easy, adaptive traits
- = Polymorphism (morphological variation within a species), cryptic species (species that look the same), purely descriptive

Question 3

What is the biological species concept?

Answer 3

Different species are separate groups that cannot interbreed

Question 4

What are the advantages and disadvantages of the biological species concept?

Answer 4

\+ = Key evolutionary concept for sexual organisms
- = Hard to do in practice, need crossing experiments (but could just compare sexual organs), hybrids and ring species (gene flow can occur around the ring but not across)

Question 5

What is the phylogenetic species concept?

Answer 5

A species is a distince group that shares a common ancestor and can be distinguished from other such groups

Question 6

What are the advantages and disadvantages of the phylogenetic species concept?

Answer 6

\+ = More practical, still based on an evolutionary concept, can apply to asexual organisms
- = Cryptic species, taxonomic inflation (splitting taxa or giving new names without discovering new taxa)

Question 7

What can be concluded when the mitochondrial phylogeny does not match the group data?

Answer 7

The males are interbreeding but the females are not

Question 8

What causes speciation?

Answer 8

1. Isolation - something stops interbreeding

2. Divergent selection - different traits are needed to take advantage of a new resource to decrease competition

Question 9

What is allopatric speciation?

Answer 9

Geographical isolation causing species to diverge

Question 10

What 3 things could happen if 2 populations re-established contact?

Answer 10

1. Pre-zygotic and post-zygotic reproductive isolation has occured
2. They can still interbreed and a hybrid is formed, the diversity is lost
3. Partial isolation - selection against inviable hybrids leads to the reinforcement of prezygotic isolation

Question 11

What is ecological speciation?

Answer 11

The divergence of a population is driven by adaptation to environments

Question 12

Give an example of ecological speciation

Answer 12

Galapagos finches:
Different environment = different food source = trophic speciation = song differences = female preferences = reproductive isolation

Question 13

What is parapatric speciation?

Give an example

Answer 13

Evolving a tolerance along a gradient

e.g. Mimulus on copper waste

Question 14

What is sympatric speciation?

Give an example

Answer 14

Host shift speciation

Parasite adapts to new host and reproduces internally