<span>Enhanced Periglacial
Geomorphic processes resulting from seasonal thawing of snow in permafrost areas where the runoff refreezes in wedges, fissures, cracks and other structures. Periglacial areas can be enviroments where freezing and rethawing significantly restructure or modify the surrounding environment.</span>
        
                    
             
        
        
        
Natural selection and speciation: 'Ecological speciation'. ... Natural selection is generally recognized as a central mechanism of evolutionary change within species. Thus, natural selection plays a major role in generating the array of phenotypic and genetic diversity observed in nature.