Evolution & Natural Selection

(By Adrian Arevalo and Rodrigo J. Gramajo)




What is the theory of evolution by natural selection?

The first person to write and investigate about the theory of evolution was Charles Darwin, he proposed that evolution occurs through natural selection due to the fact resources are limited in nature, this means that organisms with heritable traits that favor their survival and reproduction will tend to have more offspring than their peers, causing the traits to increase in frequency over generations.

What is evolution anyway?

Evolution is defined as the change or adaptation of an organism's species over time, in fact, Darwin suggested that natural selection had a lot to do with how species evolve. For instance, organisms with a specific advantage get to reproduce while others without it have less chances of survival and/or reproduction. In other terms, the organism adapts to its environment for a greater chance of survival; which can occur through mutations.



How does the fossil record, morphology, biochemistry, and adaptation provide evidence of evolution?



  • The fossil record of a given species is an important evidence for evolution because it shows that life on earth was once different from life found on earth today, plus, some of the traces might have similarities with currently existing related animals, such as the relationship with dinosaur and bird structures.

  • Organisms with closely related morphological features have more closely related molecular features, thus, proving that both organisms have had another organism in common at some point.

  • Biochemistry is the study of the basic chemistry and processes that occur in cells. The biochemistry of all living things on Earth is incredibly similar, showing that all of Earth's organisms share a common ancestry. Some of this evidence includes DNA, RNA, and proteins, in other terms, part of their chemical makeup may be related and close to another creature.

  • During adaptation, organisms adjust to new environments and changes in their current environment. The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species. This proves that adaptation makes living organisms adapt, or evolve.