Species & Speciation (Macroevolution) Flashcards
Biological Species Concept
interbreeding or potentially interbreeding populations which are reproductively isolated from other groups - challenging because some species hybridize with other species (does this mean they are not species?)
Macroevolution
Process that gives rise to new species and higher taxonomic groups
Speciation
The formation of two species from one original species
Allopatric Speciation
A population forms a new species after being geographically isolated from its parent population
Sympatric Speciation
A subset of a population forms a new species without geographic separation
Pre-zygotic isolating mechanisms
Factors that cause species to mate with their own kind
Pre-zygotic isolating mechanism: Temporal isolation
active/mating at different times of day or seasons; ex: coral spawning at different times
Pre-zygotic isolating mechanism: Ecological isolation
Different habitat preferences; ex: aquatic vs terrestrial garter snakes may live in the same area but don’t come into contact because they utilize different habitats
Pre-zygotic: Behavioral isolation
Populations are in contact but prefer mates of there own species
Pre-zygotic: Mechanical isolation
Physical incompatibility; mating is attempted but sperm transfer does not take place
Post-zygotic isolating mechanisms
Organisms may mate but have genomic incompatibility, hybrid inviability, or sterility; Ex: mules are sterile, hybrid of horses and donkeys
Adaptive radiations
Relatively fast evolution of many species from a single species
Gradualism
Evolution happens through slow, constant, and consistent change
Punctuated Equilibrium
Change happens in spurts, separated by periods of stasis
