Darwin's Postulates

Marcelo Guerra


The first of Darwin's postulates of evolution by natural selection is variability. This postulate explores the insurmountable amount of differences between individuals in a species. Both genetically and phenotypically. These differences provide variability within the species and has several consequences because each different trait can be used differently by each individual in their own environment.


The second of Darwin's postulates explores inheritance. The traits that individualize all of those who make up the species can be inherited. Passed on from generation to generation, a certain trait can make a difference that affects the whole population.


The third of Darwin's postulates relates to the species interaction with their environment. When the individuals in a species are competing for limited resources: shelter, food or water, those are the ones that are 'fittest' and survive longer and have higher chances to reproduce and have others who are like them - apt to survive.

Survival of the Fittest

The last of Darwin's postulates expresses how external conditions may affect survival of individuals. The ever-changing environment cannot be controlled by the species so the species have to adapt to it. Those who are most apt to survive, will. Some individuals don't survive long enough to reproduce while others do. Those who do have been selected by the pressures of the external environment and will reproduce and are most fit to increase survivability in their environment.


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Next Generation Science Standards. HS-LS4 Biological Evolution: Unity and Diversity. (n.d.). Retrieved April 06, 2016, from http://www.nextgenscience.org/dci-arrangement/hs-ls4-biological-evolution-unity-and-diversity

Northwestern University. (2014). Competition for Limited Resources. Retrieved April 5, 2016, from http://modelsim.tech.northwestern.edu/readings/popbio/PopBio-Reading3.1-Competiton for Resources.pdf