Adaptation and Speciation

 

The Mystery of the Cichlid:

 

 

 

Adaptation: feature of an organism that improves aspects of the performance of that organism in its environment.

 

 

v  Adaptation: adjusting to environmental challenges

o   Many different kinds of adaptations exist.

 

 

o   Adaptation does not craft organisms.  

 

 

o   Populations can adjust rapidly to environmental change.

 

 

v  Adaptation does not result in perfect organisms.

 

o   Lack of genetic variation can limit adaptation.

 

 

o   Multiple effects of developmental genes can limit adaptation.

 

 

v  Ecological trade-offs can limit adaptation.

 

 

 

 

Species

v  Morphologically distinct

 

v  Reproductively isolated

o   Prezygotic: prior to mating

 

 

o   Postzygotic: post mating

 

 

v  Speciation:

o   Often results from geographic isolation

§  Allopatric speciation: formation of new species from populations that are geographically isolated from one another

 

§  Ring species: when individuals at opposite edges of a range cannot interbreed

 

 

o   Can occur without geographic isolation

§  Sympatric speciation: formation of new species in absence of geographic isolation (Ex: polyploidy)

 

·         Polyploidy: when an individual has more than two sets of chromosomes, usually due to the failure of chromosomes to separate during meiosis

 

v  Rates of speciation

 

 

 

Implications of adaptation and speciation

 

 

 

 

 

 

 

 

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