Evolution: Darwin's Four Postulates

Learn all about the four postulates of Darwin

Postulate #1: Variation

When talking about variation, Darwin refers to it as the traits that may be different in a specie. It is often seen as an event where the different characteristics within a specie start to show. However, there is a flaw in this postulate: the limited genetic information, or the "gene pool" of that species.This has the outcome of having limited information and therefore cannot dramatically change their characteristics. However, this may actually save species or organisms in our world since having variation allows them to adapt to different conditions and continue living among us because of that trait that was different from the rest.


Inheritance is a very important postulate for Darwin, since it showed how organisms could inherit something from their parents. By what I mean with this is that in the genetic spectrum, parents could pass offsprings their traits, which connects to the first postulate. For example, there was an experiment Darwin did that showed a dog that had antipathy for butchers. This trait was passed down to its offspring and their offspring to their offspring, clearly showing that certain things were inherited.


Often called natural selection, differential survival is what ultimately determines which type of organisms will live within a specie or as a whole. In this postulate, Darwin often uses variation to explain that thanks to that "event", some species or organisms tend to live on while the others die out because of their traits. Those that survive then pass those traits that made them survive to their offsprings and they go on with their lives.


Darwin's final postulate is extinction. Extinction is when a group of organisms within a specie, or a specie as a whole, stop living among us. This is due to the postulates previously mention such as variation among species, the inheritance of the traits. For instance, because there is variation, species and organisms can have traits that will help them live, and therefore pass down those traits to their offsprings, which will help them survive in the natural selection, causing them to evade extinction. Extinction of animals is said to be essential for life, since it is supposed to determine which organisms are the strongest and better fit to survive amongst our world. It is very intriguing to see how all the postulates are connected.


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University of California Museum of Paleontology, & National Center for Science Education. (n.d.). Natural selection. Understanding Evolution. Retrieved April 08, 2016,


WGBH Educational Foundation, & Clear Blue Sky Productions, Inc. (2001). Frequently Asked Questions About Evolution. Retrieved April 08, 2016,


Yahya, H. (n.d.). The Meaning of Variation. DarwinismRefuted.com Retrieved April 08, 2016,