Chapter 24 - species and speciation Flashcards
Speciation
the process by which one species split into two or more species.
micro vs macro evolution
Micro: Changes over time in allele frequencies in a population
Macro: Broad pattern of evolution above te species level
Biological species concept
A species is a group of populations whose members have the potential to interbreed in nature and provide viable, fertile offspring
reproductive isolation
The excistence of biological factors/barriers that prevent members of two species from interbreeding and producing viable offspring
morphological species concept
distuinguishes a species by body shape and other structural features
ecological species concept
Defines a species in terms of its ecological niche, how the species act with non living and living parts of their environment
Allopatric (other country) speciation
Gene flow is interrupted when a population is divided into geographically isolated subpopulations
Sympatric (same country) speciation
Speciation occurs in populations that live in the same geographic area
Hybrid zone
a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry
temporal isolation
inability for two species to mate due to differences in timing of reproductive events (eg winter vs summer)
gametic isolation
mating occurs, but fertilization does not occur because gametes are not compatible
hybrid breakdown
fertilization occurs, but second-generation hybrid is not viable
hybrid inviability
fertilization occurs, but resulting hybrid is weak and inlike to survive to reproduce
adaptive divergence
the emergence of new forms from a shared common ancestor by adaptation to different environmental conditions
punctuated equilibrium model of evolution
the tempo of evolution consists of abrupt episodes of speciation among long periods of equilibrium
