Speciation Flashcards
What is the biological species concept?
Species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from those other groups
What does the biological species concept not work for?
Fossils and species that reproduce asexually
What is the typological species concept?
A group is a species if members conform to a type
What is a type specimen?
A specimen that is used as an example of what a species should look like
What is the evolutionary species concept?
A species is a single lineage of populations that maintains a separate evolutionary history that is got from its ancestor
What is the phylogenetic species concept?
A species is a irreducible cluster that is distinct from other clusters
What is the genealogical species concept?
An exclusive group who’s members are more closely related to each other than to others outside the group
What is the recognition species concept?
Most inclusive population of individual biparental organisms with a common fertilization system
What is the cohesion species concept?
Most inclusive population of individuals with the potential for phenotypic cohesion through intrinsic cohesion mechanisms
What are hybrids?
An individual formed by mating between different species
If the parents are distinct species, how successful would the hybrid be?
Less viable or less successful
What are the times when reproductive isolation can occur?
Pre-mating, post-mating pre-zygotic, post-mating post-zygotic
What are the pre-mating isolation barriers?
Habitat isolation
How is habitat isolation an isolating barrier?
Populations that live in different habitats can’t breed with each other
What are the 4 post-mating pre-zygotic barriers?
Temporal, behavioural, mechanical, gametic
What is behavioural isolation?
No attraction between the males and females of different species
What is temporal isolation?
Mating occurs at different times
What is mechanical isolation?
Structural differences prevent copulation or pollen transfer
What is gametic isolation?
No recognition occurs between the egg and sperm
What are the 3 post-mating post-zygotic barriers?
Hybrid breakdown, hybrid sterility, hybrid inviability
What is hybrid inviability?
The zygotes fail to develop or reach sexual maturity
What is hybrid sterility?
The hybrid can’t produce functional gametes
What is hybrid breakdown?
The offspring of the hybrids becomes sterile or inviable after a few generations
What are sibling species?
Separate reproductively isolated species that are indistinguishable based on morphological characteristics. They are distinguished based on other characteristics
What is allopatric speciation?
Separated by geographical barriers
What two phenomenon result in allopatric speciation?
Vicariance and dispersal/peripatry
Why is speciation inevitable with vicariance?
The environments on the isolated landmasses will start to change, and very little gene flow will be occurring between populations
How fast does evolution occur initially with vicariance?
Quite slow
How fast does evolution occur initially with dispersal?
Fast
What is parapatric speciation?
Speciation that occurs when two populations are neighbours, but distributions don’t overlap
What is sympatric speciation?
The develop of isolating barriers within the same geographical region
How can polyploidy cause speciation?
Polyploid hybrids are often fertile but reproductively isolated from the parent species. Diploid hybrids are often sterile
What is hybrid vigour?
Polyploid hybrids often grow faster or larger than the parental species
