Darwin's 4 Postulates
By: Ana Caty Treviño
1. In all species there is heritable variation
-Variations arise purely by chance resulting from random mutations in DNA
-Differences are obvious in many physical characteristics and extend to molecular level
2. In every generation, more offsprings are produced that can survive
-Darwin observed that many more individuals are born than survive
-Some individuals have more offspring than others
Heritable Variation
Offsprings Produced to Survive
Natural Selection
3. Survival and reproduction of individuals is not random
Natural selection acts on individuals within a population; however, it is the population that changes over time
Some phenotypic variants are passed on to offspring
Gregory Mendel's theories of inheritance(1865) confirmed Darwin's assumption that certain traits are heritable
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APA Sources
Darwin, C. (1859, Jun 3). On the Origin of Species by Means of Natural Selection, 1st edition. Retrieved April 7, 2016, from http://www.esp.org/books/darwin/origin/facsimile/
Shubin, N. (2013, May 21). Darwin's Theory of Evolution. Retrieved April 7, 2016, from http://www.science4all.org/article/darwins-theory-of-evolution/