Midterm 2 Flashcards
On what basis does the biological species concept define species?
Reproductive characteristics
What basis does the morphological species rely on?
Anatomical characteristics
What are some limitations of the morphological species concept?
1) some individuals of a species look very different in size and colouration
2) morphology can’t distinguish between species that are nearly identical in appearance.
3) tells us little about evolutionary processes that produce new species
What is the morphological species concept useful for?
1) can be used for fossilized species
2) gives clear guidelines to recognize species (guidebooks)
What is the biological species concept good for
1) good criteria for identifying species because confirms lack of gene flow
What are some disadvantages of the biological species concept?
1) not all organisms reproduce sexually
2) can’t be used for extinct organisms
3) if popns don’t overlap it is hard to tell whether they can reproduce together
How does the biological species concept explain why individuals of a species generally look alike?
Members of same gene pool share genetic traits that determine appearance
First half of biological species concept
Genetic cohesiveness: popns of same species experience gene flow, which mixes their genetic material (one large gene pool)
Second half of biological species concept
Genetic distinctness: because popns of different species are reproductively isolated, they can’t exchange genetic info
What basis does the phylogenetic species concept rely on?
Morphological and genetic sequence data
What are some disadvantages of the phylogenetic species concept?
Detailed phylogenies are not available for all organisms
What are some advantages of the phylogenetic species concept?
1) can be applied to extinct organisms
2) works for asexually reproducing species
Definition of species
Smallest evolutionary independent unit
Speciation is
The process of species formation
Which genes code for armour plating in sticklebacks?
Pitx1 and Eda genes
