Chapter 24 Flashcards
Speciation
The process which one species branches into two or more different species
Microevolution
Microevolution is the change of allele frequencies in a population over time
Macroevolution
The larger pattern of evolution
Species
A group of populations that can interbreed with eachother and produce viable healthy offspring
Formation of New Species
-Reproductie isolation- biological factor/barrier that prevents organisms from two species producing offspring
hybrid
Offspring that result from interspecial mating
Two different special barriers
Prezygotic and Postzygotic
Prezygotic Barriers
Habitat - Two species who live in different environments blocked by geography- Garter Snakes
Temporal - Two species mate during different times (seasons, year)- Skunk
Behavior-Certain mating rituals specific to a species- Blue Footed Boobie
Mechanical - Mating is attempted but physical differences prevent this- Snails
Gametic- Sperm not able to fertilize egg due to tract or biochemical reactions- urchins
Post Zygotic Barriers
Reduced Hybrid Variability- Genes of different species might impair hybrids development-Salamanders
Reduced Hybrid Fertility- Some hybrids might not be able to produce viable offspring- mule
Hybrid Breakdown- Offspring of hybrid often weak and sterile- rice
Allopatric Speciation
When a species is separated by a geological barrier and branches off into a new species
Sympatric Speciation
When a smaller population evolves into a new species without a geographic barrier. This is because of gene flow through polyploidy(extra set of chromosomes) habitat differentiation and sexual selection
Sexual Selection
When females choose their mate due to their appearance
hybrid zone
a region in which two different species mate and produce offspring
Punctuated Equilibria
This is a period of time in which a species remains static after a sudden change
