Species Flashcards
Group of species (or pops, etc) characterized by synapomorphy. Synapomorphy defines this
Monophyly
Premating barrier that occurs when species reproduce at different times (eliminates gene flow or potential mates during mate searching)
Temporal isolation
Allopatric speciation method when a population goes from mainland to an island and become isolated
Dispersal
Speciation that occurs without physical or spatial barriers due to subsets specializing on particular resources in an ecosystem
Sympatric speciation
Group that ignores evolutionary history to make new groups. Jumps around trees to pick out species for a group that don’t have to be closely related on the tree
Polyphyletic group
What is positive assortative mating an example of?
Prezygotic barrier
Species concept that expanded upon morphological concept
Biological species concept
Shared, derived (homologous) features
Synapomorphy
What is adaptive radiation an example of?
Sympatric speciation
Speciation in adjacent areas across which gene flow is restricted
Allopatry
What accompanies physical barriers in reproductive isolation that is needed for speciation?
Biologically based reproductive barriers
Non-random mating based on genotype or phenotype (like mates with like)
Positive assortative mating
Postzygotic barrier when hybrids are viable but not fertile due to things like aneuploid gametes (chromosomes have different genes or morphologies and thus cant segregate properly)
Hybrid sterility
Variation within populations (genetic differences), geographic variation between populations (look different in different areas but interbreed where pops meet), and sibling species (reproductively different but look alike) are all observations which lead to what species concept?
Biological
ALL OF THE EXTRA INFO ON SPECIATION
ALL OF THE EXTRA INFO ON SPECIATION
Maybe the most critical premating barrier in animals, when males don’t engage females or females don’t respond to males
Behavioral (ethological) isolation (lack of interest)
What acts as the initial barrier to gene flow in parapatric speciation that ultimately leads to speciation
Physical distance
Concept stating species are defined on the basis of physical features
Morphological species concept
This type of postmating barrier is important in many marine invertebrates and nearly all plants
Gametic isolation
Means newer
Derived
Fertilization takes place but may not result in a successful offspring
Postzygotic barriers
A complete lineage. All the descendants of a common ancestor
Clade or monophyletic group
What are the two ways of allopatric speciation to occur?
Dispersal and vicariance
Means that species are in the same place and are cryptic/sibling but not the same
Incipient
Speciation that occurs due to isolation by distance. This only works for species that don’t travel extreme distances
Parapatric speciation
Group with a common ancestor and excluding one of the descendants
Paraphyletic group
Postzygotic barrier when embryo dies shortly after fertilization or hybrid offspring develop and then die
Zygote or hybrid mortality
What are the four limits to the biological species concept?
- parthenogenic or asexual species; its hard to identify asexual organisms as species in this concept
- hybrid zones; mules are a horse/donkey hybrid and are fine, but sterile
- extinct and extant species cant be identified without any breeding data
- geographically separated pops could potentially breed
Same thing as a monophyletic group
Clade
Hybrid zygotes are formed but have reduced fitness
Postzygotic barriers
Barrier created before zygote formation
Prezygotic barrier
Isolating genomes from each other to get two separate genomes
Reproductive isolation
What are rind species? What species concept do they limit?
Species that start in one spot as one but go around and become different. Limit biological concept because we don’t know if the different pops can breed
Concept that is often most powerful and looks at phylogenic trees and seeing if individuals group together or not
Phylogenetic species concept
Phenomena that prevent gene flow between pops or members of the same pop
Isolating mechanisms
The mechanisms by which populations attain reproductive isolation
Speciation
What are species the outcome of?
Reproductive isolation
Concept stating species are populations of variable individuals connected through gene flow
Biological species concept
Mating or gamete transfer occurs, but zygotes are not formed
Postmating/prezygotic barriers
Allopatric speciation method when a population gets separated due to a geological event like the formation of mountains, river, etc.
Vicariance
What are the commonalities of all species concepts (3)?
- species are pops linked by history
- characterized by shared, derived attributes
- genetic and morphological continuity maintained by interbreeding
Features that impede transfer of gametes to members of other species
Premating barriers
If niches are empty, subsets of a pop can specialize to fill new niches
Adaptive radiation
Means ancestral
Basal
Premating barrier that occurs when organisms spend their whole life in a single place or on a single host so they don’t get a chance to meet
Habitat isolation
Postmating barrier when the eggs and sperm are mechanically incompatible
Mechanical isolation
Concept stating if two organisms can reproduce, they are a species and if they cant, they aren’t a species
Biological species concept
Speciation that is most important in animals and occurs when a population becomes geographically isolated
Allopatric speciation
Prevent mating between pops. May outright prevent or just decrease the freq or incidence of mating
Prezygotic barriers
Postmating barrier when eggs don’t recognize sperm due to incompatible receptors or nuclei don’t fuse
Gametic isolation
3 major species concepts
Biological, morphological, phylogenetic
