Darwin's Four Postulates

Rodrigo Paredes

Four Postulates

I. There is heritable variation in all species.

II. In every generation more offspring is created that can survive.

III. The survival and reproduction of species is not random. Some species have better chance of survival and reproduction due to their phenotype, they are also better suited to their environment and are able to live longer.

IV. Some phenotype variants are passed on to the offspring. The more fit the phenotype are for survival the more they are represented.

The second postulate is very interesting. This is because it talks how we improve ourselves upon every generation. For example from the transition of the neanderthal to the modern human our skull got bigger because our brain got bigger, we were smarter. Also our jaws got smaller and that explains why we have wisdom teeth because we do not anymore use these teeth they were before for the use of the neanderthals. Other interesting things that happen with evolution is that we slowly adapt that we no longer need the wisdom teeth. For example I do not have any wisdom teeth and slowly most of the next generations will be the same.

I also think that it is very interesting to see how species evolve in different ways according to its environment. I like octopuses and they have a great ability to camouflage from its prey. This means that they have adapted to survive in a habitat when they are not top of the food chain. The species that could not adapt have not survived this is the idea of natural selection.


Dobzhansky, Theodosius (March 1956). "Genetics of Natural Populations. XXV. Genetic Changes in Populations of Drosophila pseudoobscura and Drosophila persimilis in Some Localities in California". Evolution (Hoboken, NJ: John Wiley & Sons on behalf of the Society for the Study of Evolution)

Penny, David; Poole, Anthony (December 1999). "The nature of the last universal common ancestor". Current Opinion in Genetics & Development(Amsterdam, the Netherlands: Elsevier)