24 Flashcards
Factors can alter the allele frequencies in populations
Genetic drift, natural selection, gene flow, mutation
Allopatric
Geographic seperation
Sympatric
Still live in same area
Geographic isolation
Species occur in different areas so theres a physical barrier - allopatric speciation.
Ecological isolation
Species occur in same region, but occupy differ habitats so rarely encounter each other - repoduceiveyl isolated
Temporal isolation
Species that breed during different times of day, different seasons, or different hears cannot mix gamates - reproductive isolation and sympatric speication
Behavioral isolation
Unique behavioral patterns and rituals isolate species - reproductive isolation
Mechanical isolation
Morphological differ can prevent successful mating - reproductive isolation and lack of fit
Gametic isolation
Similar to mechanism but the sperm cannot penetrate egg ( lock and key) and sperm cannot surive in feml reproductive tract.
Reduced hybrid viability
Life span is too short
Reduced hybrid fertility
Can reproduce like the mule
Hybrid breakdown
Hybrids may be fertile and viable in first generation, but when they mate offsprint are feeble or sterile
Polyploidy
Too many chromosome more common in plants
Hybrid zones
A region in which members of differs species mate and produce hybrids
Gradualism
Gradual divergence over long spans of time
