Chapter 24 Flashcards
What is required for the formation of new species?
Absence of gene flow
What are the 2 types of barriers?
- Prezygotic barriers
- Postzygotic barriers
What are the types of prezygotic barriers?
- Habitat
- Temporal
- Behavioral
- Mechanical
- Gametic
What occurs in habitat isolation?
Two species occupy different habitats
How does mechanical isolation occur?
Morphological differences prevent 2 species from mating
How does gametic isolation occur?
Sperm is not able to fertilize egg
What are the types of postzygotic barriers?
- Reduced hybrid viability
- Reduced hybrid fertility
- Hybrid breakdown
What are the 2 main ways that speciation can occur?
- Allopatric
- Sympatric
What are the 3 mechanisms that can lead to sympatric speciation?
- Polyploidy
- Habitat differentiation
- Sexual selection
What is polyploidy? What are the 2 types of polyploids?
- Condition that results in extra chromosomes
- Autopolyploid (all from same species) and allopolyploid (sets deriving from different species
What is a hybrid zone?
Area in which different species meet and mate
What are the 3 possible outcomes when 2 related species meet and mate in a hybrid zone?
- Strengthen reproductive barriers
- Weaken reproductive barriers
- Continued formation of hybrids
Punctuated equilibrium
Period of stasis for organism followed by sudden change
Speciation
Process by which one species splits into two
