Lecture 24 Flashcards
Three major species concepts
- Typological (morphological)
- Biological Species Concept
- Phylogenetic
Typological (morphological)
- based on appearance, smell, sound
- not very effective (within a species, there can be morphological difference)
Angler Fish (morphological)
- Females are much larger than males
- males are parasitic on the females and they bite the females and lose every part of them other than their testes
Certain butterflies (typological)
- different mimicry patterns
mimicry rings - poisonous colours, defining them is interbreed
Dogs (typological)
- can have dramatic morphological differences, but same species
- Dogs are as diverse as Carnivora
- Dogs explore new morphological space
Biological Species Concept (BSC)
- Groups of actually or potentially interbreeding natural populations which are reproductive isolated from other such groups
- BSC allows for some gene flow btwn different species
- speciation is a process
Problem: difficult for allopatric population (not particularly useful for fossils)
Phylogenetic
- Reciprocal monophyly
- “a species is a discrete lineage, propagated, ancestor to descendent through time which is reocognizably distinct from other such lineages and shares a distinct evolutionary history
Reciprocal monophyly
- Every species is more closely related to their own group than to any other species
Phylogenetic species concept
Problem: can’t be used for fossils, Only reflects time, not reproductive barriers
Who will breed with who?
Problem: Most species will be able to successful be able to breed with one other species
ex. Tigers and lions can breed together although they are considered different species, their offspring can also sometimes breed again
Various mechanisms of speciation
- Uniform natural selection
- Divergent natural selection (“Ecological” speciation)
- Genetic drift
- Polyploidy
- Hybridization
- Sexual selection
- Cytoplasmic incompatibliity
