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Evolution is a theory that states that all living organisms descended from a common ancestor that lived at around 3.8 years ago. [1] Evolution describes descent with modification of organisms, and is separated into two types of evolution: small scale, (microevolution) or change within a population in between generations, and large scale, (macroevolution) or the creation of new organisms from a common ancestor. [2] The mechanisms of evolution are natural selection, gene flow, genetic drift, and mutation. [3]

MechanismsEdit

Evolution happens through several different mechanisms: natural selection, gene flow, genetic drift, and mutation. [3]

Natural SelectionEdit

Main article: Natural Selection

Natural selection is the process in which certain traits become more or less prevalent due to selection by the environment. A population may have certain individuals with unique traits. If the environment favours those traits, which are usually caused by mutation, individuals are more likely to survive if they have those traits. The traits later spread through the entire population through heredity. [4]
Natselect

A diagram showing natural selection.

Gene FlowEdit

Main article: Gene Flow

Gene flow is the process by which certain genes are spread between populations. Barriers to gene flow, such as geographical barriers or geological events, eventually result in speciation over long periods of time. [5]

Genetic DriftEdit

Main article: Genetic Drift

Genetic drift is the random fluctuation of gene frequencies, or the frequency a certain allele is found in a population. [6]

MutationEdit

Main article: Mutations

A mutation is a change in the genes of an organism. [7] It can be caused by erroneous copying of a DNA strand, or external influences such as radiation.[8]

SpeciationEdit

Under construction

Transitional FossilsEdit

A transitional fossil is a fossil of a creature between two other types of creatures, one of whom descending from it and the other of whom an ancestor to it.

Criticism of evolutionEdit

Under construction

ReferencesEdit

  1. https://en.wikipedia.org/wiki/Evolution "Evolution" Wikimedia Foundation. Accessed 22 February 2014.
  2. http://evolution.berkeley.edu/evolibrary/article/evo_02 "An introduction to evolution" Understanding Evolution. University of California, Berkeley. Accessed 22 February 2014.
  3. 3.0 3.1 http://evolution.berkeley.edu/evolibrary/article/evo_14 "Mechanisms: the processes of evolution" Understanding Evolution. University of California, Berkeley. Accessed 22 February 2014.
  4. http://evolution.berkeley.edu/evolibrary/article/evo_25 "Natural Selection" Understanding Evolution. University of California, Berkeley. Accessed 22 February 2014.
  5. http://www.biology-online.org/dictionary/Gene_Flow "Gene Flow" Biology Online. Accessed 15 July, 2014
  6. http://www.talkorigins.org/faqs/genetic-drift.html "Random Genetic Drift" Evolution FAQs. Talk.Origins. Accessed 15 July, 2014.
  7. http://evolution.berkeley.edu/evolibrary/article/mutations_01 "DNA and Mutations" Understanding Evolution. University of California, Berkeley. Accessed 15 July 2014.
  8. http://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_04