Speciation Flashcards
Define speciation.
The process by which one species becomes two species.
Define the morphological species concept.
Species are groups of individuals that share morphological characteristics in common.
Describe the biological species concept.
Species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other groups
Who developed the biological species concept?
Theodosious Dobzhansky & Ernst Mayr
What are the three types of reproductive isolation?
Premating
Post-mating, pre-zygotic
Post-zyogtic
What is meant by premating as a type of reproductive isolation?
Different breeding/flowering times;
Incompatible sex organs
Prevents copulation
What is post-mating, pre-zygotic reproductive isolation?
Mating but not fertilization
What is post-zygotic reproductive isolation?
Offspring die or are infertile.
Describe the phylogenetic species concept.
A cluster of organisms that form a monophyletic clade.
What are the two steps to determining a species using the phylogenetic species concept?
o Estimating phylogeny
o Determining “groups”
Describe the pros of the morphological species concept (3).
- Easy, anyone can do it
- Doesn’t require expensive genetics
- Objective criteria
Describe the cons of the morphological species concept (4).
- Inaccurate, in part because what traits do you measure?
- Variation within species
- Cryptic species
- Convergent evolution
Describe the pros of the biological species concept (3).
- Objective definition
- Experimentally testable
- Based on the biology of organisms
Describe the cons of the biological species concept (3).
- Not always practical or ethical
- Infertility is not absolute
- Doesn’t work with everything (e.g., asexual species like bacteria)
Describe the pros of the phylogenetic species concept (3).
- Applicable to any group of organisms
- Reflects evolutionary history
- Objective