Lecture 22 & 23 & 24: Species and Speciation Flashcards
Define the morphological species concept.
Species are distinguished by morphological differences.
Define the biological species concept.
Species are groups of interbreeding natural populations that are reproductively isolated from other such groups.
Define the phylogenetic species concept.
a single lineage of ancestor-descendant populations which maintains its identity from other such lineages.
Define a ring species
a connected series of neighbouring populations, each of which can interbreed with closely sited related populations, but for which there exist at least two “end” populations in the series, which are too distantly related to interbreed, though there is a potential gene flow
What are the four premating/prezygotic reproductive isolating mechanism?
- Ecological isolation
- Temporal isolation
- Mechanical isolation
- Ethological isolation
What are the four postmating/postzygotic reproductive isolating mechanisms?
- Gamete incompatibility (prezygotic)
- Hybrid inviability
- Hybrid sterility
- F2 breakdown
What is ecological isolation?
When two species are unable to mate because they occupy different ecologies.
What it ethological isolation?
When two species are unable to make because the have different mating behaviors.
What is temporal isolation?
When the reproductive timing of species are not in synch.
What is mechanical isolation?
When species are morphologically incompatible.
Define sibling species.
Species that are close relatives to one another.
Define cryptic species.
Species that are not easily distinguished, but are true species.
What is hybrid inviability?
When the embryo of two species doesn’t live.
What is hybrid sterility?
When hybrids develop, but are sterile and thus cannot reproduce.
What is F2 breakdown?
When the F1 generation is fertile, but thee next generation (F2) are sterile or have reduced fitness?
