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SPECIATION (Sources of variation: (Point mutations, Duplications,…
SPECIATION
Sources of variation:
Point mutations
Duplications
Insertions
Deletions
Independant assortment
Recombination
Mechanisms of speciation
Allopatric
Speciation due to geographical isolation
Types:
Vicariance
2 new species created
Dispersal
1 new species created
Founder effect
Allele frequency of new different from old
Can lead to bottleneck
Parapatric
Small peripheral populations exploit a different niche
Different geographical range
Peripatric
Small peripheral populations exploit a different niche
Same geographical range
Sympatric
Speciation in one geographical range
Ring species
Species:
Basic unit of biological classification and taxonomical rank
Multiple concepts:
Biological
Reproductive isolation
Limited to current species only + chordata
Phylogenetical
Indépendant lineages
Morphological
Form
Ecological
Distinct niches
Nominalism
Names only
Evolutionary significant units
Population focused
Features:
Variation
Isolation
Decreased gene flow
Selection
Divergence
Mechanisms of Isolation
Prezygotic
Geographical Isolation
Mechanical Isolation
Temporal Isolation
Behavioral Isolation
Postzygotic
Gamete Incompatibility
Hybrid mortality
Hybrid infertility F1
Hybrid breakdown F2
Niches:
Fundamental niche (theoretical)
Possible resources
Realised niche (actual)
Resources actually used due to limiting factors
Hybridisation
Results:
Reinforcement
Fusion
Stability
Polymorphism
Different morphologies with a species