There are a number of common misunderstandings about evolution, some of which have hindered its general acceptance.[42][43][44] Critics of evolution frequently assert that evolution is "just a theory", a misunderstanding of the meaning of theory in a scientific context: whereas in colloquial speech a theory is a conjecture or guess, in science a theory is simply an explanation.[45] Critics also state that evolution is not a fact, although from a scientific viewpoint evolution is considered both a theory and a fact.[46][47][48] A related, more extreme claim is that evolution is a "theory in crisis", generally based on misrepresenting the scientific support and evidence for evolutionary theory.[49]
Another common misunderstanding is the idea that one species, such as humans, can be more "highly evolved" or "adanced" than another. It is often assumed that evolution must lead to greater complexity, or that devolution ("backwards" evolution) can occur. Scientists consider evolution a non-directional process that does not proceed toward any ultimate goal; advancements are only situational, and organisms' complexity can either increase, decrease, or stay the same, depending on which is advantageous and thus selected for.[50]
Evolution is also frequently oversimplified as stating that humans evolved from monkeys; based on this, some critics of evolution argue that monkeys should no longer exist. This misunderstands speciation, which frequently involves a subset of a population cladogenetically splitting off before speciating, rather than an entire species simply turning into a new one. Additionally, biologists have never claimed that humans evolved from monkeys—only that humans and monkeys share a common ancestor, as do all organisms.[51]
It is also frequently claimed that speciation has only been inferred, never directly observed. In reality, the evolution of numerous new species has been observed.[52] A similar claim is that only microevolution, not macroevolution, has been observed; however, macroevolution has been observed as well, and modern evolutionary synthesis draws little distinction between the two, considering macroevolution to simply be microevolution on a larger scale.[53]
Other widespread misunderstandings of evolution include the idea that evolution violates the second law of thermodynamics, which applies to isolated systems, not self-organizing organisms;[46] and that evolution cannot create new physical information, although this regularly occurs whenever a novel mutation or gene duplication arises.[54]
http://en.wikipedia.org/wiki/Misunderstandings_about_evolution