Who is Darwin?
Darwins's Four Postulates
1. Individuals within species are variable
2. Variations are heritable
3. Individuals vary in survival and reproductive success
4. Survival and reproduction are not random.
Individuals within species are variable
So in the first postulate of Darwin he states that individual organisms have different traits which they posses. For example hair color, height, skin color etc.
Variations are heritable
The second postulate of Darwin states that some of the trait differences are heritable and are passed on from a parent to an offspring. So basically the ones who are more fit phenotypes are to be better represented in the next generation.
Individuals vary in survival and reproductive success
Survival and reproduction are not random.
According to Darwin's line of evidence, postulate number four indicates that the individuals who survive and reproduce the most have the most favorable variation and are naturally selected. It follows that the characteristics of the population will change with each generation until the population becomes different from the original one. This process is known as evolution.
Jones, K. (May 20, 2009). Charles Darwin. Retrieved April 07, 2016. http://www.biography.com/people/charles-darwin-9266433
Road, T. (n.d.). Introduction to Ecological Genetics. Retrieved April 07, 2016.
Smith, D. (2012). Darwin’s Theory of Evolution. Retrieved April 07, 2016. http://www.science4all.org/article/darwins-theory-of-evolution/
Williams, J. (n.d.). Ch1. Adaptation by Natural Selection. Retrieved April 07, 2016. http://www.wwnorton.com/college/anthro/bioanth/ch1/chap1.htm