Darwin's 4 Postulates

Juan Pablo Treviño

Charles Darwin

  1. Species are variable
  2. Variations are passed along to offspring
  3. Each generation produces more amount of species that can survive
  4. Survival and reproduction are not random


These four postulates are the cause of Natural Selection according to the great scientist Charles Darwin.

Species are Variable

Charles Darwin noticed that specific species were not all exactly the same, for example monkeys look almost identical, but all are different. These observations could not be proven in any way since there was no technology available for Darwin to use. Now we know why an how these variations work. Everything is about the DNA. The DNA has only very slight changes in their code, that makes every individual different to each other. DNA mutation is also something that is very important to variation, take for example the finches Darwin studied in the Galapagos island. He noticed that the finches had different beaks in different places. He determined that they had evolved because of the food that were available to them.
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Variation is passed along to offspring

In short, this postulate is basically inheritance. As we all know we are who we are because of our ancestors. We even look like our parents and our brothers and sisters. This is because were inherit traits from our ancestors. Darwin believed that these traits came from the cells that the parents give to their offspring. Species develop to fit the environment they are in, and that they change to adapt to the situation. These changes occur over many generations. Darwin's study of the finches also backs up this postulate since it shows that finches with a unique beak had offspring with the same unique beak. This study and discovery is shown in the DNA of each species. Know we can see the differences and patterns that each offspring has compared to the parents. Everything is based on information that is taken by using statistics and probability.
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Each Generation produces more amount of Species that can Survive

Survival is the main goal of every animal. We are programmed to have the extinct of protecting us of any danger and we would do anything to save ourselves, that is our nature. Through many generations species have been adapting to every danger or difficulty they have encountered. For example the study of pocket mice's fur color shows how this works. Pocket mice always had a very light color to them there was no other option. When pocket mice's were forced to live in a different place were there are many dark rocks. The pocket mice were an easy prey because they could be seen because of the contrast in colors. A mutation came along and there was a darker pocket mice. This pocket mice had an advantage over the others since it could camouflage. This mice started reproducing and reproducing until there were more dark than light. This shows how more species are produced over time, in order for more to survive.
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Survival and Reproduction are not Random

Survival and reproduction is definitely not random since there are many factors that can affect the outcome. Certain species have certain traits that gives them the advantage over others, this will cause them to reproduce more and survive. This is a matter of natural selection also since it is somewhat of a survival of the fittest. Species that keep on reproducing will become stronger and stronger so that the species can survive in future generations. If you keep record of the actual numbers will start noticing patterns on what affects what during survival and reproduction.
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Bibliography

Introduction to Ecological Genetics. (n.d.). Retrieved April 07, 2016, from

http://ib.berkeley.edu/courses/ib162/Week1.htm


Jennings, J. (2013). Lecture Outline - Evolution 1. History of Evolutionary thought 2. Principles of Evolution by Natural Selection 3. Modern Synthesis: Combining Darwin. Retrieved April 07, 2016, from http://slideplayer.com/slide/7848582/


Pujari, S. (Nd) 4 Main Theories of Evolution (explained with diagram and tables). YourArticleLibrary. Retrieved: Apr 7, 2016.

http://www.yourarticlelibrary.com/biology/4-main-theories-of-evolution-explained-with-diagram-and-tables-biology/27220/


Rock Pocket Mice. (n.d.). Retrieved April 07, 2016, from http://learn.genetics.utah.edu/content/selection/comparative/