DARWIN'S FOUR POSTULATES
By: Daniel Garcia
Natural Selection
Overall, The 4 Postulates:
- Variation - There is a lot of variety within species
- Inheritance - Offspring looks like their parents, gets traits from them
- Differential Survival - External conditions can affect survival
- Extinction - Some traits are not suited for survival and will lead species to die out
Variation
All populations of all organisms and individuals vary enormously, no two individual are equal. This genetic variation is due to genetic mutations, random mating or fertilization, and recombination of chromatids of homologous chromosomes in meiosis. It is crucial to natural selection because the frequency of alleles increases or decreases depending on which traits prove useful for survival. The more variety, the more chances a population has at obtaining a favorable allele to keep in the upcoming generations.
Inheritance
Inheritance is the procedure of receiving genetic traits genetically transmitted from parents to offspring. Darwin concluded that more favorable traits were passed on at a higher frequently than useless or detrimental traits. Inheritance is what allows species to evolve and survive.
Differential Survival
Differential of survival is the theory that food production and populations are directly correlated. Limited quantities of space & resources lead to a struggle for survival results, and as a result those that are the most fit can only survive. The reason behind it is basically that because more organisms are born each generation that can survive, the excess need to be killed by famine or disease. Limited quantities of space and resources lead to struggle for survival so everyone is competing and a result only the most fit can survive.
Extinction
This postulate goes along with the cycle of life and natural selection. Over time, species become extinct for many reasons. Some species die out because they no longer have the resources they need. Other’s because they are not the fittest species to survive.
Bibliography
Evansville. (n.d.). Natural Selection. Evensville Education. Retrieved April 5, 2016.
http://faculty.evansville.edu/de3/b32003/lecture%20summaries/selection.pdf
Martin, S. (Apr 2016). Apocalypse Now?. Express News. https://www.express.co.uk/news/science/658686/Apocalypse-now-Experts-say-Earth-in-middle-of-MASS-EXTINCTION-and-here-s-how-to-survive
Pianka, Eric. (2008) Convergent Evolution. Retrieved April 5, 2016, from http://www.zo.utexas.edu/courses/THOC/Convergence.html