Darwin's Third Postulate

By: Juan Flores

Differential Survival

This is one of the great Charles Darwin's postulates, more specifically the third: Differential Survival. Differential Survival is basically the belief that external conditions/events can affect a species survival. This is a topic which can be seen nowadays very prominently; Humans have basically dominated the whole world, and we are establishing businesses, houses, apartments, and cities in areas where animals live in, like forests. This is harming every species which lives in those ecosystems, since they're having their homes destroyed by deforestation. Another external factor affecting a species survival is pollution. For example, oil spills killing large portions of marine life, garbage in the ocean affecting creatures, and more. External conditions certainly do affect a species survival, because all of these situations certainly do kill a large amount of the population in these species. Another form of external conditions affecting species survival are volcanoes. If a volcano erupts in a light-dirt area, a big portion of that area will become black. Animals which where suited to camouflage in the light areas are now in dark areas, affecting their survival, so they have to adapt, this can be seen in the images below.


Browne, J. (2011). Charles Darwin: The power of place. Knopf.