Final exam- Speciation Flashcards
Define Biological Species Concept
Identifies species based on whether individuals can mate with eachother and produce viable and fertile offspring
Biological Species Concept
Prezygotic reproductive barriers
Two categories of reproductive barriers
Before zygote: hinders mating/fertilizing of the egg
Biological Species Concept
Postzygotic reproductive barriers
Two categories of reproductive barriers
Hinders zygotic development/viability or fertility
Biological species concept
What type of barrier is Differences in mating timing of reproduction?
ex. September vs late winter
Temporal differences
Prezygotic: hinders the ability to mate
Biological Species concept
What type of barrier is habitat isolation?
ex. Apple fly vs Hawthorn berry
Microhabitat isolation
Prezygotic barrier: individuals rarely encounter eachother to reproduce
Biological species concept
What type of barrier is differences in mating rituals?
Ex. firefly dancing
Behavioral
Prezygotic: hinders mating ability
Biological species concept
What type of barrier is incompatible reproductive structures?
ex. spiked penis of beetle
Mechanical
Prezygotic: reproductive structures dont align and/or eggs and sperm arent compatible
Biological species concept
What type of barrier is hybrid sterility?
Ex. Mule (donkey x horse)
Postzygotic barrier
What are limitations for biological species concept?
Cant be used on fossil forms or asexual populations
Define Morphospecies concept
A group organisms that are morphologically similar to one another and morphologically distinct from other groups.
What is a limitation of the morphospecies concept?
- Different species may look very similar
- Individuals of the same species may look different in different life stages
Define Ecological Species Concept
Classifies organisms as the same species if they have the same ecological niche
ex. same habitat, food, predators ect.
What are some limitations with the ecological species concept?
- Some species change their niche over time (larva vs adult)
- Different species can share the same niche
Define Phylogenetic species concept
The smallest group of individuals descended from a
common ancestor, which form a single lineage with distinguishing synapomorphies.
Does this group represent the smallest group with synapomorphies?
What are some limitations for the Phylogenetic Species concept?
Trees require a LOT of resources to construct
Define Speciation
Evolutionary process by which new species form
- We will use BSC to define
What are the 3 steps to speciation?
Is order important?
- Gene flow stops: All or part of population becomes genetically isolated from others
- Isolated populations diverge genetically due to mutations, natural selection and genetic drift acting on populations independantly
- Reproductive isolation: pre/post zygotic barriers evolve
YESS
What would happen if two populations that were isolated from eachother came into contact again?
They would be unable to mate and/or produce viable/fertile offspring
Define Allopatric Speciation
Two mechanisms of speciation
Geographic seperation of populations due to some barrier or distance
- NO gene flow between pops
Allo = other place
Define Sympatric Speciation
Two mechanisms of speciation
Reproductive isolation between populations, no physical barrier
Sym = same place
Allopatric speciation by
Vicariance
Physically splitting one population into two or more due to the formation of a geographic barrier
ex. river/road/glaciers
Allopatric speciation by
Dispersal
A few members of a population move to a new area
= founders event (UNI-DIRECTIONAL)
Sympatric selection by
Disruptive selection
Mean trait values are selected against, populations start to diverge in two different directions at the same time
Ex. Hawthorn/Apple Maggot Fly
