Evolution and Species Change
Evolution occurs when heritable characteristics of a species change
As many of you must know already, Charles Darwin came up with the Theory of Evolution. Evolution (defined by dictionary.reference.com) is a "change in the gene pool of a population from generation to generation by such processes as mutation, natural selection and genetic drift".
Natural Selection, as you may have heard several times before, is the survival of the fittest (this quote was formed by Herbert Spencer). This theory suggests that the organisms that adapt the best to the environment will survive for a longer period of time and hence, they are able to generate a new generation.
Genetic Drift occurs through a random process where due to some random chance, some individuals have a few more descendants compared to other individuals and so they are the lucky individuals and not necessarily the 'fitter' individual. Species can also migrate to different locations and then they would start adapting to their new environment, creating variation within their classification. This is evidence for adaptive radiation. |
Mutation is when there is a change in the gene sequence (change in nucleotide) within an organism. This may occur during DNA replication or due to any severe environmental changes such as an exposure to high dosages of radiation. These changes must occur within the sex cells (sperms and eggs) in order for it to be passed onto the next generation.
Variations occur within Evolution, causing a diverse and complex life on Earth, giving each species food they require, skills they require and competition in order to survive. Even though evolution makes us all different, it tells us that we are all, in fact, the same in terms of coming from the same heritage, having the same or similar ancestors - all from one (micro)organism around 3.8 billion years ago as evolutionists predict.
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