Isolating Mechanisms and Artificial Selection (OCR A-Level Biology A): Flashcards
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Isolating mechanisms
Isolating mechanisms
Causes of separation when populations divide into sub-groups
Allopatric speciation
Allopatric speciation
Speciation via geographical separation (e.g. rivers, mountains)
Sympatric speciation
Sympatric speciation
Speciation without geographic separation, same location
Temporal isolation
Temporal isolation
Shifted breeding cycles mean fertile at different times
Polyploidy in plants
Polyploidy in plants
Chromosome doubling allows sterile hybrids to become fertile
Artificial selection
Artificial selection
Humans direct breeding by selecting desirable features
Continuous variation
Continuous variation
Trait determined by many genes (e.g. milk yield in cattle)
Modern bread wheat (T. aestivum) chromosome type & number
Modern bread wheat (T. aestivum) chromosome type & number
Hexaploid with 42 chromosomes
Ancestral species of modern domestic dogs
Ancestral species of modern domestic dogs
Grey wolf
Example: health issue from dog selective breeding
Example: health issue from dog selective breeding
Hip dysplasia in large breeds, breathing issues in bulldogs