Darwin's Postulates
What are they? Why do they matter?
#1 - Variation
All species have variation within them. This is why they are able to survive and adapt. There are two types of variation, genotypic variation, and phenotypic variation. Genotypic variation is variation in the genes. This occurs through mutations, and through the mixing of the genes of two parents when they reproduce. Phenotypic variation is a genotypic mutation that is visually expressed. For example, you could have a genotypic mutation that is recessive, so it does not show, therefore you don't have the phenotypic variation. The concept of variation is extremely important in a species because if species all have very similar genes there is a very severe danger of sicknesses that could wipe out the entire species.
#2 - Inheritance
Inheritance is what we get genetically from our biological parents. When two organisms reproduce, their DNA is mixed and together they form a new combination of DNA with their own traits. The offspring will have it's own unique mix of it's parents genes. This is why it's called inheritance, because the offspring will receive both dominant and recessive genes from its parents.
#3 - Differential Survival
This postulate is about how external conditions affect survival. These are also known as biotic and abiotic factors. Darwin's explains natural selection by using differential survival, meaning that when a species is challenged by difficult external factors, only the strongest and fittest will survive, eliminating those that were weak or did not adapt.
#4 - Extinction
Extinction of a species can happen for many different reasons, in essence, the species is not able to survive and reproduce to replace the deceased, so the entire species ceases to exist. This may happen due to a natural disaster, over hunting, deseas, or any other abiotic or biotic factor that challenges the species and wins.
Sources:
D. (n.d.). Darwin was Right | Genetic Variation. Retrieved April 04, 2016, from http://www.darwinwasright.org/genetics.html
Interpretation of a dream in which you saw «Dinosaurs». (n.d.). Retrieved April 04, 2016, from http://weknowyourdreamz.com/dinosaurs.html
M. (n.d.). Phenotypic Variation Explained. Retrieved April 04, 2016, from http://nov79.com/mr/exph.html
Patel, N. (2013). 23 Cute Bunny Pictures You Should Check Today - SloDive. Retrieved April 04, 2016, from http://slodive.com/inspiration/23-cute-bunny-pictures-you-should-check-today/