FAQ: Common questions regarding evolution
|» What is evolution?|
» Is evolution a fact or theory?
» How do new species arise?
» How is new information created?
» How fast does evolution happen?
|Evolution is technically defined as any cumulative genetic change from one generation to the next. Although evolution is generally considered to occur over a much larger timescale where such small individual changes have accumulated and radically altered many traits of a species.|
|If evolution is a fact why do scientists still call it the THEORY of evolution? The mistake is to assume that scientists use theory in the same sense that laypeople do. But in fact it is the virtual opposite! Scientists call a theory (in the widely used sense), a HYPOTHESIS. That is, a prediction which has been made by a scientist, or group of scientists, but has not yet been tested to substantiate its truth value. When such a hypothesis HAS been rigorously tested to the highest standards, as demanded by the Scientific Method, and it still stands (though probably slightly altered from the original prediction), it then becomes known as a "theory", such as the theory of relativity. Therefore, theory is not the opposite of fact, but is rather the SAME as fact.|
|New species arise by the process called speciation. There are four main modes of speciation: allopatric, sympatric, parapatric and peripatric. The main one of these which is responsible for the evolution of most species is allopatric speciation. An originally conspecific population is somehow separated into two or more isolated groups. If these groups stay isolated for a long enough period of time, they will diverge genetically via natural selection and genetic drift. The remaining three modes all stress ecological isolation rather than geographical. Members of both species still regularly interact with each other, but they are now distinct species due to some isolating feature of their ecology such as diet, when they are active (i.e. diurnal, nocturnal, crepuscular), mating preferences etc.|
|New genetic information is created when genes or whole segments of DNA get replicated. These replicated portions of DNA then mutate and take on different and new roles in the building of an organism.|
|The speed of evolution is not uniform. Species can remain in stasis for many tens of millions of years because evolution for these species would be detrimental. They have become virtually perfectly adapted. Whereas at the other end of the spectrum, species can evolve in a timescale measured in years, because their generation time is measured in weeks or months, such as insects.|