Species and Geographic Model of Speciation Flashcards
(22 cards)
Name evolution traits of mutation
- ongoing stochastic process
- genome variation is mostly neutral
- allelic variation present
- has QTL (quantitative trait loci)
Describe evolution traits of genetic drift
- alleles fixed or lost based on probability
- powerful force in small populations
Describe evolution traits of Quantitiative traits
- complex genetic basis
- environmental influences
- epistasis
Describe evolution traits of natural selection
- produces adpatations
- genome signatures
- tied to specific environments
Describe gene flow evolution traits
- transfer of genetic information from population to population
- maintains a species
- blocks can start the speciation process
How many species defintions are there atm?
26 at least lol
Name the three types of species definitions
Phylogenetic Species Concept, Biological Species Concept, and Ecological Species Concept
Phylogenetic Species Concept
“a diagnosable cluster of individuals within which there is a parental pattern of ancestry and descent, beyond which there is not, and
which exhibits a pattern of phylogenetic ancestry and descent among units of like
kind”
Describe some conditions of the Phylogenetic Species Concept
- Monophyletic groups or tip taxon can be considered a species.
- Molecular data often used for PSCs.
- This concept is dependent upon the correct species phylogeny.
- This concept applies to asexual and sexual taxa.
- can be used for any organism really (fossils, certain character states, etc.)
Describe some of the hurdles of the Phylogenetic species concept
-phylogenetic trees are hypotheses, so your evidence in your defense could turn out to be untrue
- sequence divergence amongst species; how much is really there?
- gaps in records
Phylogenetic species concept: describe species on a tree
“tip” on phylogeny, that is, the smallest set of organisms that share an ancestor and can be distinguished from other such sets; under this definition, a ring species is a simple species that encompasses a lot of phenotypic variation
Describe the Evolutionary Species Concept
An evolutionary species is a lineage of interbreeding organisms, reproductively isolated from other lineages, that has a beginning, an end, and a distinct evolutionary trajectory
Describe some conditions of the evolutionary species concept
- Taxa that are morphologically constrained (canalized) may be divergent in DNA sequences but not in morphology.
- Doesn’t describe mechanism of species formation.
- This species definition if often used by paleontologists.
Name hurdle of evolutionary species concept
cannot always be relied on due to missing fossil records
Describe the Hominid evolution chart and its importance
- it is attempting to show trajectories and it is seen for several taxa; somes species extinct while some persist
- H. erectus is the 1st taxon with significant brain expansion
- H. sapiens (us!) included
Biological Species Concept
group of actually or potentially interbreeding natural populations which are
reproductively isolated from other such groups
restrictive in definition
Name the hurdles of the biological species concept
- Can’t apply to asexually reproducing taxa
- Fossil record cannot provide supporting evidence
restrictive defintion
Example of biological species concept
donkeys and horses are separate in taxonomy, since offspring are sterile
lygers the same
What history do the recent fossils of Neanderthals from France provide
- it shows they share traits with Croatians and other modern human groups, suggesting interbreeding. Evidence from whole nuclear genome sequence of hominin fossils
supports this.
This could provide evidence in the future of our genes resulting from various interbreeding occurences
Who came up with the Phylogenetic species concept?
Eldredge and Cracraft
Who created the Biological Species concept?
Mayr
Who created the Evolutionary Species Concept?
Wiley
