What evidence is used to support evolutionary theory?

Answer 1

Darwin noted similarities in species far removed from each other. His observations of finch beaks on the Galapagos Islands was one key piece of information helping him formulate his theory. Darwin did not realize these birds were finches to begin with. Only after he brought specimens back to England did an ornithologist point out what his birds were. The adaptations in beaks was one of the things that helped him piece together his theory.

Other evidence existed in the numerous fossils Darwin accumulated. These fossils showed gradual changes in species over vast periods of time. Birds and reptiles are diapsids, whereas all mammals (including humans) are synapsids. Darwin conjectured some fossil might exist to show a link between reptiles and birds, and that fossil was Archeopteryx. Since then we have found numerous other examples of transitions between species.

Yet more evidence is found in genetic similarities. On the basis of their anatomy organisms can be grouped into tree like structures of nested hierarchies. These nested hierarchies are evidence of common ancestry. Any other classification system would constitute evidence against common ancestry, and hence against evolution. However, genetic analysis produces identical overlapping tree structures. This is considered excellent evidence for the soundness of the foundational theory of Biology.

Answer 2

From a scientific point of view - advances in analysis methods have enabled us to determine that all animal species on this planet share a proportion of DNA sequences - from less than 1 percent right up to 99.9 percent. That would only happen if we all shared a common ancestor millions of years ago.

Answer 3

Summarizing:

zoology, morphology: nested hierarchies, atavisms, homologies and so on.

Developmental biology: nested hierarchies and atavisms in developmental patterns.

Genetics, comparative genomics: nested hierarchies, ERV's, ancient fusion sites, etc.

Palaeontology: sequences of diverging morphological progressions, transitional forms, and so on.

Answer 4

Evolution is the change in allele frequency over time in a population of organisms. There is no evidence against this fact. Fossils and inhereited traits all speak toward evolution. If you are looking for more evidence of evolution you don't have to look very far.

Answer 5

Evolution by natural selection was first proposed as such by Charles Darwin in his book On the Origin of Species in 1859. His original evidence was collected during his extensive field work in the Galapagos islands. He was in particular interested in birds and tortoises, and demonstrated that even within the Galapagos animals and plants on the separate islands had selected highly specific traits that allowed for their survival.

A good concise example of evolution can be found here: http://en.wikipedia.org/wiki/Peppered_moth_evolution

Its important to keep in mind that evolution is not as simple a concept as many in the main stream 'culture wars' want us to believe on either side and Darwin himself felt that many people took his concept in the wrong direction. To really understand what Darwin was trying to get say, I would read On the Origin Of Species for yourself.

Answer 6

That's a difficult question, because the independent lines of evidence supporting common descent, descent with modification and natural selection are really too numerous to list.

Perhaps I can try and summarize the most important lines of evidence.

First: common descent.

The most telling clue as to the origin of modern lifeforms is not in the fossil record: it's in our shapes and in our behaviours and in our genes. If we look at the shapes and genes of all living animals, we find that any attempt to form a comprehensive classification system based on their traits result in a set of nested hierarchies: sets within sets within sets. This trend is easily visible at the morphological level, but is exactly matched by observations at the molecular, the genetic, the developmental and the behavioural level. Such a pattern is exactly what we would expect if diverse modern lifeforms had emerged from shared ancestors, which in turn share ancestors even further back, and so on - but cannot be explained otherwise.

Most of the evidence we have are examples of how life conforms to the nested hierarchies of biology. ERV's, atavisms, human chromosome #2, the GULO gene in apes and guinea pigs, and so on. The exact same pattern we find in the fossil record, diverging towards modern forms with time - which independently confirms the conclusion drawn from morphology and genetics.

Second: natural selection.

Darwin based his conclusions on both the distribution of closely similar species across geography he observed during his voyages on the Beagle, and on observations in the breeding of fowl and livestock, some of which he confirmed experimentally. He noted how human keepers selected for certain traits in order to amplify them in offspring, and speculated that the same thing must happen in nature, where selection occurs not through artificial selection, but through competition of variants for mating opportunities and resources: *natural* selection. He saw this confirmed in the distribution of model species like the finches that were named after him, the various forms of which seem to radiate outward from a common origin.

Since then, we've come to understand the genetic mechanisms involved much better, allowing us to make specific predictions about what kind of patterns we should find in our genes if natural selection is true. Most of this goes way beyond my expertise, or beyond what one can comfortably explain in a simple Answersarticle.

I suggest therefore that you look up some of the more specific claims, predictions and evidences in the link listed in the related links below

The website below addresses common descent mostly, but the site does offer a lot of links leading to more information about evolution in general, including natural selection.
New species appear over time. No multi-celled life forms existed 2 billion years ago, therefore they must have evolved from single-celled life forms.

Unfortunately, this is not very well thought through. The assumption is that the single celled organism developed gradually from one cell to two cell to four cell and so on until a multiple celled creature resulted. But while there are vast numbers of single celled organisms in the world, there is no evidence of two or four or eight or sixteen celled organisms. And for a single celled organism to evolve directly to a multiple celled creature (at least 100 or more cells) is not credible. There is no evidence for it.
Evolution is a large subject, about which many books have been published; some of the more distinguished authors of books about evolution are Stephen J. Gould and Richard Dawkins. I could not really do justice to the subject without writing too long an answer for this web-site. But to give a general idea, the evidence for the theory of evolution includes analysis of the varieties of living creatures and their similarities to, and differences from each other, analysis of the fossil record of organisms which previously existed but are now extinct, analysis of the biochemistry and genetics of various organisms, observation of the adaptation of species (such as, for example, bacteria which adapt to antibiotics and become resistant to them), observation of fetal development in which the fetus is seen to go through earlier evolutionary states (a process which is succinctly if somewhat esoterically described by the phrase "ontogeny recapitulates phylogeny") and observation of vestigial organs (in humans, there is the appendix; whales have vestigial leg bones, etc.), and various other things. There is a lot.
Originally it was supported by things such as fossils. As time has gone on, and more discoveries and advances in technology are made, things such as DNA and carbon dating have given further support to the theory.
The Theory of Evolution was formulated by Charles Darwin. Through various researches, his ideas are now supported by evidences in the fields of biochemistry, comparative anatomy, biogeography, comparative embryology, molecular biology, Paleontology, modern examples and radioisotope dating.
The structure of the forelimb of a bird is similar in structure to that of the forelimb of a mammal, suggesting that both descended from a common ancestor. This similarity is an example of evidence that supports the Theory of Evolution.
In spite of creationist claims to the contrary, evolution really does tell us about the origin of species.

Some examples of early transitional species:

• Tiktaalik roseae is the name of a newly discovered lobe-finned fossil fish from the late Devonian period, that is a transitional form to amphibians. It had basic wrist bones and simple fingers, as well as the robust ribcage necessitated by existence out of water.

  There would be no conceivable explanation for Tiktaalik other than evolution.

• Another example of a clearly transitional species is the 380 million-year-old fossil of a primitive fish, Gogonasus. It had fins strong enough to support its weight in shallow water and propel itself along. A scan of the fossil, using a three-dimensional X-ray microscope, revealed its skeleton had several features that were more like those of a four-legged land animal, or tetrapod, than a fish. They included the structure of its middle ear and the existence of precursors of the forearm bones in its fins: the radius and ulna.

  Here was a fish that had already evolved to a point where it had much in common with later land animals.

• A recently discovered 220-million year old fossil, Odontochelys semitestacea, is further evidence of evolution. This new species of turtle had a fully formed shell on its underside, but only a small partial shell on its back, extending from its backbone. Scientists had long debated how the turtle shell evolved. As well as a partial shell, Odontochelys semitestaceaalso had ribs that had begun to widen, thus demonstrating that the fully developed shell of later turtles evolved from the ribs of earlier species.

  Odontochelys semitestacea is one more piece in the jigsaw that shows conclusively how life on Earth evolved from earlier species.

Answer Evidence for evolution comes from comparative embryology and observations of much similarity among embryos of many different animals: early embryos of vertebrates are similar, fish-like gills and other anatomical structures appear in many vertebrate embryos, limb bones of animals alike in number, useless body parts (such as tail bone in Homo sapiens).

Also, according to Darwin, natural selection and variation are the supporting factors for evolution. As species evolve and differ from each other their genes also change over time, and genetic diversity is a precondition for evolution. Thus, evolution occurs because certain individuals are better adapted for their environment (due to the gene change) and are better able to survive environmental pressures and become parents for the next generation.

Another Answer · many people think that "survival of the fittest" means only the biggest and strongest survive, it actually means that those best suited to (fitting) their environment will survive

· many people believe that evolution is still a theory when actually there has been more than enough physical evidence to place evolution into a generally accepted science

· there is a physical connection between all living things that is not just theory, there are three innate traits identified in all living things, supporting one's life, defending one's life and reproducing one's life.

Biogeography is the study of species over space and time. It predicts that (if evolution is correct) species closely related to each other should be found close together (except for creatures with very high mobility like sea-faring birds, humans and animals moved around by humans)

What we find is that, for example, marsupial mammals live almost exclusively in Australia, while placental mammals are rare there. Marsupials are much more closely related to each other than they are to other mammals.

Also rabbits were introduced to Australia by humans rather recently. In Australia there are no predators which eat rabbits and no herbivores capable of competing with them, so rabbits thrive. If evolution were not true then there is no reason for rabbits not to have been found in Australia originally as they seem to do so well there. However biogeography suggests that as rabbits evolved in Europe, Asia or North America (all connected by land bridges in the recent past) they cannot be found in Australia because it is isolated from those continents.

There is too much of it to describe here. Please go to the related link, '29+ Evidences for Macroevolution'.
Such evidence is both abundant and compelling. First, there is the taxonomy of species created by Linnaeus. This hierarchical system strongly implies modern species shared common ancestry, and it is this implication that prompted Charles Darwin to set out on his voyage on the Beagle. During that voyage Darwin encountered numerous fossils that helped him put forth and hone the theory of evolution. For example, Darwin noted fossils of extinct sloths, which highlighted the fact this species had undergone significant change over geologic time. Darwin was also aware that the earliest fossils were all "primitive" cambrian marine organisms. It was apparent that at the earliest stages, there were no terrestrial life forms.

Since Darwin's time we have developed techniques of molecular biology and studies of embryology to further demonstrate the ancestral kinship shared by living organisms. Our own species, for example, shares a defect common to other primates (non functioning GULO gene which is responsible for the synthesis of ascorbic acid) almost no other mammal has. In addition, we can show that our chromosome number 2 is the result of the fusion of two primate chromosomes.

All of the scientific data comprises a veritable rock solid mountain of evidence detailing the pathways of evolution of the course of the past six hundred million years.

Answer 7

There are vast numbers of observations that, taken together, make an undeniable - and undenied, at least in scientific circles - case for evolutionary theory, as pioneered by Charles Darwin, to be at least fundamentally true. They range from pseudo-genes to embryological atavisms to fossil intermediates, and so on. If I must mention only a single thing, then I will probably choose to mention a line of evidence, one feature of life that permeates all levels of observation - from the morphology of fossils and living things to the genes that guide their embryological development: the fact that all life, at all levels of observation, in virtually every detail, follows a pattern of nested hierarchies. This means that, taken together, the differences and similarities between all the different lifeforms form a pattern of sets within sets within sets, such as would be formed by a family tree.

Answer 8

Evolution is not about belief, so 'evolutionists' do not so much believe in evolution as accept the overwhelming evidence and the fact that the Theory of Evolution is so well proven.

Charles Darwin developed the Theory of Evolution by Natural Selection before most of the fossil evidence for the theory existed. He looked at the micro-evolution practised by pigeon breeders, the evidence on the Galapagos Islands and elsewhere, and realised that evolution was the only explanation that made sense. He saw that related species were to be found in close proximity, evidence of evolution from a single parent species, whereas a single act of Special Creation ought to have placed the species anywhere on the globe where the environment was suitable.

The fossil record shows clear evidence of evolution over a period of more than a billion years. Certainly, at first, there were no transitional species among the many species that had been found, although scientists saw much that did confirm the Theory of Evolution. That has changed, because many transitional species have been found. A recently discovered 220-million year old fossil, Odontochelys semitestacea, is a new species of turtle that had a fully formed shell on its underside, but only a small partial shell on its back, extending from its backbone. As well as a partial shell, Odontochelys semitestaceaalso had ribs that had begun to widen, thus demonstrating that the fully developed shell of later turtles evolved from the ribs of earlier species. Tiktaalik roseae is the name of a newly discovered lobe-finned fossil fish from the late Devonian period, that is a transitional form to amphibians, with basic wrist bones and simple fingers, as well as the robust ribcage necessitated by existence out of water. Odontochelys semitestacea and Tiktaalik roseae are two more pieces in the jigsaw that shows conclusively how life on Earth evolved from earlier species.

Scientists can now use DNA evidence from modern species to support the fossil record, as evidence of evolution.

For more information, please visit: http://christianity.answers.com/theology/the-story-of-creation

Answer 9

There can be numerous types of evidence:

• Molecular evidence
• Genetic evidence
• Fossil evidence
• Homologous/analogous structures

Answer 10

Fossils.