Darwin's Postulates
By: Balbina Zertuche
Darwin's First Postulate - Variation
Variation is a change or difference in condition, amount, or level, typically in certain limits. An example of variation within species is for instance a jaguar and a black jaguar, they come from the same family but they look different because of a mutation. In this postulate Darwin explains that it is not due to evolution since it is a mutation, and a variation from one species, the other specie doesn't stop to exist it is just a difference from one animal to another, and it isn't something that is added to the genetic information, it is just something that is different.
Darwin's Second Postulate - Inheritance
Inheritance was the belief of an offspring looking a like their parents. Darwin was a great believer that every child looked like their parent because of inheritance. Darwin wrote a book called "The Variation of Animals and Plants Under Domestication" which explained many examples about examples of the heredity transmission of adaptations. He used examples of how dogs could inherit something a parent had learned before, or how a plant could inherit a new adaptation form.
Darwin's Third Postulate - Differential Survival
Differential Survival is how the external conditions can affect survival. The process of differential survival is known as natural selection. Which are non-genetic changes that occur during an organisms life-span. Like increases in muscle mass due to exercise and diet, which cannot be passed to the next generation and is an example of evolution. Difference from variation, which is not a change in evolution, differential survival is something like not being born with the wisdom teeth which is a change in evolution.
Darwin's Fourth Postulate - Extinction
Darwin's fourth and last postulate is evolution which is that a species has some traits which are not suited for survival and those with them will eventually die, and there will be no more left. Extinction has a role in evolution, that during the past years in history species have died, and new ones have evolved. Darwin viewed extinction as something that should occur, as something ordinary and necessary in evolution. Extinction was viewed by Darwin as a cycle, where species that don't have the potential to evolve die, and new ones which are species that do have that potential to survive and evolve remain in earth.
Sources
AMNH. (2011). Extinction or Opportunity. Retrieved April 07, 2016, from http://www.amnh.org/exhibitions/darwin/evolution-today/how-do-new-species-evolve/extinction-or-opportunity
Foundation, E. (2001). Evolution. Retrieved April 07, 2016, from http://www.pbs.org/wgbh/evolution/library/faq/cat01.html
L. E. (2010). Darwinism Refuted.com. Retrieved April 07, 2016, from http://www.darwinismrefuted.com/origin_of_species_01.html
Sheldrake, R. (2015, June 8). Darwinian Inheritance and the Evolution of Evolutionary Theory - Campaign for Open Science. Retrieved April 07, 2016, from http://opensciences.org/blogs/open-sciences-blog/darwinian-inheritance-and-the-evolution-of-evolutionary-theory