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What is Evolution? Evolution Defined and Explained

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.

Evidence for Evolution - Is There Evidence for Evolution?
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...

Direct Evidence for Evolution - Evidence for Evolutionary Theory
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 …

Observation & Evidence for Evolution - What We Observe of Evolution
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...

Inferential Evidence for Evolution - Evidence for Inferring Evolution
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...

Usefulness of Evolution - How is Evolution Useful?
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...

Observing Evolution - How Evolution Has Been Observed
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...

Genetics & Mutations - How Genetic Mutations Drive Evolution
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.

Homologies & Evolution - Homologies as Inferential Evidence f…
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...

Fossils & Evolution - Fossil Evidence Supports Evolution
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...

Hierarchy of Life - How the Hierarchy of Life Points to Evolution
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...

Junk DNA - Junk DNA & Evolution
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...

Genetic & Protein Homologies - How Genetic & Protein Homologies Prove Evolution
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.

Embryonic Homologies - How Embryonic Homologies Support Evolution
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.

Vestigial Organs - What Vestigial Organs Say about Evolution
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 - Anatomical Homologies and Evolution
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...

Evolution is a Scientific Theory - Evolution Meets Criteria for Scien…
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...

Biogeography & Evolution - How Biogeography Supports Evolution
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 FAQ: What is Evolution?
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...

Evolution Defined: What is Evolution and Evolutionary Theory? How Is The...
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....

Evolution: Fact Or Theory? How Can It Be Both? What's the Difference?
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...

Microevolution vs Macroevolution: Is There A Difference Between...
'Microevolution' and 'macroevolution' are two terms often used by creationists when trying to attack evolution, but few creationists understand what microevolution and macroevolution really are. The fact is, there isn't any fundamental difference.

Is Evolution Scientific?
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.

Abiogenesis and the Origin of Life
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.

Evolution FAQ: Evolution Chronology
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.

Basic Definitions of Macroevolution & Microevolution
Because the distinction between macroevolution and microevolution is fairly minor, you won't find the terms defined and separated in every science book. You don't have to look too hard and too far to find the definitions, though, and it's important to note that macroevolution and microevolution are defined consistently across many types of...

Creationists on Microevolution & Macroevolution
It is not possible to get an accurate picture of evolution from creationist literature - creationists simply won't use key scientific terminology the same way scientists do. Because the subject is scientific, though, this means they are using key terminology incorrectly. What's more, it's implausible that they are ignorant of the fact that they...

Debates Over Microevolution & Macroevolution
The basic scientific perspective on macroevolution and microevolution is that macroevolution is lots of microevolution over time, but there are other natural processes that influence the course of macroevolution. This isn't much of a revelation because there are all sorts of natural processes that influence the course of microevolution as well....

Macroevolution Is Microevolution - Macroevolution as a Product of Mic…
Scientists don't draw much distinction between macroevolution and microevolution because macroevolution is ultimately produced by microevolution - lots of microevolution over long periods of time. The basic mechanisms of macroevolution are also the basic mechanisms of microevolution. There is a difference, but it's primarily a difference of...

Macroevolution & Microevolution
Macroevolution vs. microevolution is probably the primary issue debated between evolution and creationism, but is a minor issue in evolutionary theory itself. Few actual working scientists agree that there is much of a distinction between macroevolution and microevolution and most pay little attention to it, but creationists have seized upon it...

Creationist Misrepresentations of Macroevolution & Microevolution
Almost everything creationists say or write about evolution is, ultimately some sort of misrepresentation of science, but there is a special grouping of misrepresentations dealing with microevolution and macroevolution specifically. This is because questions about microevolution and macroevolution lie at the heart of creationist arguments...

Evolution and the Missing Link: Why Is It Missing?
The term 'missing link' is one that is seen quite a lot in the context of evolutionary theory, but it's also one that's frequently misused.

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