Evolution can be a difficult concept for people to come to terms with, especially if they do not have much experience with life sciences. Is evolution a fact or a theory? Does evolution explain the origin of life or not? These are important questions which people need to be able to understand and answer. Evolution is not a minor matter - it is, in fact, the cornerstone of all modern biology.
In debates over evolution and creationism, it is common for creationists' to demand for "proof" of evolution (common descent). Science doesn't deal in absolute proofs, though. Scientific theories are provisional and are supported by evidence or data. Proof in science is not the same as proof in mathematics; in science, proof is gradually achieved through the accumulation of evidence which is best…
The direct evidence for common descent and evolution are enabling evidences. They demonstrate that common descent is possible and maybe even likely. However, they don't conclusively show that common descent occurred because no one was actually there to observe it over such a long period of time (the same problem that exists when
the…Creationists like to argue that evolution can't be science because we can't directly observe evolution in action — and since science requires direct observation, evolution is necessarily excluded from the realm of science. This is a false definition of science, but more than that it's also a complete misrepresentation of how humans actually work when it comes to forming conclusions about the world.
Inferential evidence for evolution is evidence that does not involve direct observation of evolution but from which we can infer that evolution has occurred. The three main kinds of inferential evidence for common descent are contemporary homologies, biogeography, and the fossil record. Inferential evidence is open to interpretation, but this doesn’t mean inferential evidence is weak. The more …
Theodosius Dobzhansky, one of the 20th century's most eminent evolutionary biologists, had it right when he said, 'Nothing in biology makes sense except in light of evolution.' Evolution is the conceptual paradigm that ties together all the life sciences. Without the explanatory framework provided by the theory of evolution, the biological sciences would be disjointed and much within biology would not make sense. Denial of evolution thus amounts to denial of the foundations of modern biology
The most basic direct evidence of evolution is our direct observation of evolution occurring. This is also the most basic lie which creationists tell about evolution because they constantly claim that evolution has never been observed when, in fact, it's been observed both in the lab and the field repeatedly. Creationists count on this lie getting traction because they lie about what evolution is and repeat the lies often enough that they are believed through sheer, dishonest repetition.
The basic definition of evolution is a change in the gene pool of a population of organisms over time. All of evolution is based on genetic change. Scientists still have a lot to learn about the workings of genetic code, but science has built up a large volume of knowledge about how the genetic material of living organisms works. We have a pretty good understanding of what DNA does in general and, equally important to evolution, how DNA changes.
Homology has a specific meaning in evolution, but I will not be using that to avoid circular reasoning — we can't "prove" evolution using terms that assume evolution. I will use a more general meaning for homology: similarities between species that are not functionally necessary. In pre-evolutionary terms, the alternative type of similarity would be an analogous similarity: the wings of birds a…
When you hear talk of evidence for evolution, the first thing that frequently comes to mind for most people are fossils. The fossil record has one important, unique characteristic: it is our only actual glimpse into the past where common descent is proposed to have taken place. As such it provides invaluable evidence for common descent. The fossil record is not "complete" (fossilization is a rare event, so this is to be expected), but there is still a wealth of fossil information.
The many homologies between living organisms offer powerful evidence for evolution in and of themselves. However, there is another way of looking at the data that ties the various homologies together into an even more powerful form of evidence: the hierarchy of life. There are only a couple of ways in which all life on earth could be related and once you visualize them, it becomes clear that only one pattern is supported by all the physical evidence: evolutionary theory.
The most interesting genetic homologies are in junk DNA. Often called "noncoding DNA," junk DNA has no apparent function or produce no protein but may help regulate the gene. When DNA is transcribed, pieces either do not get transcribed at all or are only partially transcribed, with no functional protein produced. You can cut out or modify most junk DNA without affecting the organism. There are several varieties of junk DNA including pseudogenes, introns, transposons and retroposons.
Biochemical homologies provide some of the strongest evidence for evolution - partly because of the level of detail they provide and partly because the nature of some of the homologies makes any explanation other than evolution seem even more farfetched than with the larger-scale homologies. There are a variety of different avenues of biochemical evidence for evolution, but most of them are either examinations of genetics or of proteins - genetic homologies and protein homologies.
Most anatomical homologies, whether active or vestigial, are present in the adult members of a species. A few anatomical homologies, however, only appear briefly during the embryonic stage of an animal's development. These short-lived anatomical homologies are referred to as embryonic homologies and serve as evidence that the species in question is related to other species where the organs or anatomical structures persist past the embryonic stage and through adulthood.
Most of the obvious anatomical homologies are between anatomical structures which are in active use by the species in question, but some anatomical homologies involve structures which are no longer needed but which also haven't disappeared entirely. A vestigial organ or structure is any organ or structure found in a species which is not being used as it is in other species. Contrary to popular belief, vestigial organs and vestigial structures aren't necessarily useless or functionless.
Anatomical homologies are morphological or physiological similarities between different species of plants or animals. Comparative anatomy, which is the study of anatomical homologies, is the source of most traditional evidence for evolution and common descent. Anatomical homologies continue to provide many examples of deep relationships between species which are best or only explained through evolutionary theory when the similarities simply don't make sense from a functional perspective.
Creationists complain that evolution isn't valid or genuine science, but exactly the opposite is the case: evolution meets the criteria generally accepted by scientists as defining science and the vast majority of scientists accept evolution as science. Evolution is the central organizing framework for the biological sciences and is just as scientifically valid as analogous theories in other scie…
Biogeography is the study of the the distribution of life forms over geographical areas. Biogeography not only provides significant inferential evidence for evolution and common descent, but it also provides what creationists like to deny is possible in evolution: testable predictions. Biogeography is split into two areas: ecological biogeography which is concerned with current distribution patterns and historical biogeography which is concerned with long-term and large-scale distributions.
Evolution is a difficult concept for some to understand, especially if they don't have much experience with life science. Is evolution a fact or a theory? Does evolution explain the origin of life? These are important questions which people need to be able to understand and answer. Evolution is not minor - it is, in fact, the cornerstone of all modern biology. Theodosius Dobzhansky wrote: "Nothin…
Evolution can be a confusing term because it is used in more than one way. Many people in the general population have developed an incorrect understanding of evolution for a number of reasons. One is the misinformation spread by creationists - by misrepresenting evolution, they may hope that it will be easier to get people to disregard it. Another is simple ignorance of the topic itself and the specific ways in which science uses certain terminology.
There is some confusion about evolution as a fact and evolution as a theory. Often you can find critics claiming that evolution is 'just a theory' rather than a fact, as if that were supposed to demonstrate that it shouldn't be given serious consideration. Such arguments are based upon a misunderstanding of both the nature of science and the nature of evolution.
There is one particular aspect of evolution that needs to be given specific attention: the somewhat artificial distinction between what is called 'microevolution' and 'macroevolution', two terms often used by creationists in their attempts to critique evolution and evolutionary theory.
This question isn't as simple as it sounds, but the short answer is yes, evolution is science. Evolution meets the criteria generally accepted by scientists as defining science, and the vast majority of scientists accept evolution as science.
As if evolution and evolutionary theory were not already confusing enough, many creationists complicate matters even further by promulgating the mistaken idea that evolution is the same as abiogenesis. One common way this is done is to argue that evolution cannot explain how life began while creationism can and, therefore, creationism is superior to evolution.
Timeline of events surrounding evolutionary theory. Events include those related to the development of evolutionary theory and the controversy surrounding the teaching of evolution and creationism in schools.
