Types of selection
Selective selection
Favours intermediate phenotype and against
both extreme phenotypes. Intermediate
phenotype has high chance to survive while
individual with extreme phenotypes has less
chance to survive
ex; birth's weight of human babies
Directional selection
Favours one extreme phenotype and against
another extreme phenotype. The dominant
extreme phenotype will survive while the
opposite has lower chance to survive
ex; industrial melanism of peppered moth
Disruptive selection
Favours both extreme phenotypes and
against intermediate phenotype. Both
extreme phenotypes have high chance to
survive while intermediate phenotype are
less likely to survive
ex; beak sizes and shapes of black bellied seed crackers finches
in Cameroon
Selective selection
Favours intermediate phenotype and against
both extreme phenotypes. Intermediate
phenotype has high chance to survive while
individual with extreme phenotypes has less
chance to survive
ex; birth's weight of human babies
Directional selection
Favours one extreme phenotype and against
another extreme phenotype. The dominant
extreme phenotype will survive while the
opposite has lower chance to survive
ex; industrial melanism of peppered moth
Disruptive selection
Favours both extreme phenotypes and
against intermediate phenotype. Both
extreme phenotypes have high chance to
survive while intermediate phenotype are
less likely to survive
ex; beak sizes and shapes of black bellied seed crackers finches
in Cameroon
