User:Axel147

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Hi and

please read the unit of selection article. it was changed. i hope many things can become clearer now

[edit] Compromise version 3...

Laypeople often use the word "theory" to signify "conjecture", "speculation", or "opinion". In science however, a theory is a model of the world (or some portion of it) that makes predictions that can be tested through controlled experiments. Evolution is a theory as it explains and interprets observations, and is used to make successful predictions.

Evolution is also a "fact". The word fact is often used by scientists to refer to empirical data, objective verifiable observations. But fact is also used in a wider sense to include any hypothesis for which there is overwhelming evidence. In this usage "the sun is at the center of the solar system" and "objects fall due to gravity" are considered to be facts. The fact of evolution is the observation that populations of one species of organism do, over time, change and form new species. This has been extensively supported by empirical evidence.

This fact is itself explained using theories that provide deeper understanding: the causes of evolution are the mechanisms of natural selection, genetic drift etc. "The theory of evolution" is generally used to refer to the idea of evolutionary change ("descent with modification") together with the mechanisms that cause it.