Lecture 21: Speciation and Hybridization Flashcards
What is a species
phenotypic similarity based on how similar the species look
Sympatric
species in the same geographic space
Allopatric
species belonging to different geographical locations
what is another widely used definition of a species
phylogenetic species concept, looking at genetic similarities
Taxonomic (morphological)
this is based on the measurable differences of varying individuals
Biological Species concept
based on if 2 individuals can reproduce with one another.
What species concept did Darwin look at
taxonomic which he explained to be incidental microevolutionary
Explain some of the points of BSC
focuses on the process
tests that if the geological Barries go away will the 2 be capable of reproducing
if two individuals reproduce successfully in a lab does it mean they belong to the same group?
No because this doesn’t guarantee that they will do so in the wild
Where does speciation occur
allopatric speciation is more common because evolution with minimal gene flow, so they end up evolving separately due to geographical distance
What causes reproductive isolation
anything that goes wrong during post-zygotic phase
What are pre-zygotic barriers
geography
behaviour
genetic structure
sperm-egg compatibility
What are post-zygotic barriers
intrinsic (sterility)
extrinsic (populations that cannot survive the environment
How and why do organisms diverge?
mutations
natural selection
genetic drift
Why do we have so many species on earth
due to speciation
