WHAT IS SELECTIVE PRESSURE + WHERE DO THEY COME FROM?
Selective pressures are environmental factors or influences which may lessen reproduction in a species’ population and therefore contributes to evolutionary change or even extinction through natural selection.
Examples of selective pressures include competition, predation, land clearance, pollutants, diseases and illnesses, climate change and parasitism.
A famous example of selective pressure is the long neck and legs of giraffes. Because food sources became exhausted, or subject to large competition in the giraffe habitat, selection pressures favoured the specimens in the population with longer legs and necks. These taller individuals could reach higher vegetation, and would therefore have a possibility to survive any struggle for existence and pass on their traits to their offspring. This meant that only the healthiest and longest giraffes reproduced many offspring, resulting in the common image of the giraffe that is known today since the genetic variation lived on through the generations.
Selective pressures are environmental factors or influences which may lessen reproduction in a species’ population and therefore contributes to evolutionary change or even extinction through natural selection.
Examples of selective pressures include competition, predation, land clearance, pollutants, diseases and illnesses, climate change and parasitism.
A famous example of selective pressure is the long neck and legs of giraffes. Because food sources became exhausted, or subject to large competition in the giraffe habitat, selection pressures favoured the specimens in the population with longer legs and necks. These taller individuals could reach higher vegetation, and would therefore have a possibility to survive any struggle for existence and pass on their traits to their offspring. This meant that only the healthiest and longest giraffes reproduced many offspring, resulting in the common image of the giraffe that is known today since the genetic variation lived on through the generations.