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Evolution

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Etymology:

"Evolution" is from the Latin evolutio, "unrolling", from evolvere, to unroll.

This article is about the evolution of living things. For a broader view of evolution, see evolutionary worldview.

Evolution, in biology, refers to universal common descent—the theory that all life on earth is descended from a common ancestor or ancestral gene pool, by gradual divergence of genetic material.

Contents

Definition

Evolution is broadly described as the theory that all life on Earth has come about by modification from previous living things, forming a 'family tree' of all living things, tracing back to a common ancestor. Douglas Theobold, for example, wrote that "Universal common ancestry (UCA) is a central pillar of modern evolutionary theory."[1] Evolution has also been more narrowly defined as a change of genetic material within a population over time,[2] a definition which fails to convey the idea of universal common descent.

Evolution is said to occur by means of variation and selection occurring over millions of years. The key mechanism is natural selection, selecting between different variants in a population so that traits which result in a reproductive advantage to an organism become widespread while traits which result in a reproductive disadvantage become rare. Natural selection requires variation to work on and this is generated in three main ways: genetic recombination during sexual reproduction, the transfer of genes between populations, and mutations. Natural selection is not synonymous with evolution itself, but it is occasionally used to describe the entire system of variation and selection.

The concept of natural selection was first described by creationist Edward Blyth in 1835, although he did not use the term.[3] Charles Darwin first used the term in his 1859 book On the Origin of Species where he compared artificial selection with natural selection.

The theory of evolution can be distinguished from the concept that separate kinds were created by God with the capacity to adapt, within limits, to their environment. While the later concept allows for animals to adapt to a limited extent, it does not allow for change beyond the boundaries apparently delineated by the created kinds.

Evolution as theory

Evolution is known as the "theory of evolution", where the word "theory" is used in the scientific sense of "a well-substantiated explanation of some aspect of the natural world"[4] This puts it a step above a hypothesis, which is "a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena".[5] Evolution is a form of origins science, that is, a study of how things began, as it purports to explain the origin of the great amount of variety in living things. As such, it is concerned with the past, which limits the ability of science to test claims made about it.

Evolution is also claimed to be a "fact"[6] and the distinction here is that the theory of evolution is the explanation of how and why the (supposedly) observed phenonemon (the "fact") of evolution occurs.

The controversy over evolution is over the supposed fact of evolution—does it, or did it, occur at all—as much as over the mechanisms of evolution (the theory).

Evolutionists will often liken the theory of evolution to the theory of gravity. However, gravity is something that occurs in the present, its existence is not disputed, and it can very readily be observed and measured. From these ongoing measurements, a theory can be readily tested. Evolution, in contrast, is something that is claimed to have occurred over many millions of years and most if not all of which has not been observed. Additionally the theory states that while evolution is still happening today it happens too slowly to be observed in most cases. Therefore, the theory of evolution cannot be tested as can the theory of gravity.

Furthermore, the theory of evolution, unlike the theory of gravity, is a whole host of different albeit intertwining explanations. Karl Popper described evolution as "a metaphysical research program—a possible framework for testable scientific theories."[7]

The all-encompassing nature of evolution claimed by its supporters was also reflected in Theodosius Dobzhansky's famous (but disputed) claim that "Nothing in biology makes sense except in the light of evolution."[8] Supporters often claim that biology cannot be done without accepting evolution, demonstrating that evolution is not merely claimed to be a theory, but the basis of entire disciplines.

Mechanism

Evolution is supposed to start by genetic changes being introduced to a population. Then, natural selection favours the populations which have genetic changes which give them a survival value over populations which don't.

Genetic changes can occur in three main ways: recombination through sexual reproduction, gene transfer, and mutations.

The offspring of sexually-reproducing organisms get half of their genetic material from one parent and the other half from the other parent. As both parents have non-identical genetic information, the genetic information of the offspring is different again from both parents. This means that the offspring may be missing some genetic information that is present in one of their parents, and this can result in changes that have survival value. See Genetic information#Differentiation and speciation for a fuller explanation. Note, though, that this process doesn't introduce new genetic information.

Some organisms such as bacteria can transfer genetic information between individuals, and viruses can be used to accomplish this. Note that this process also doesn't introduce new genetic information; it merely transfers copies of existing genetic information.

When sexually-reproducing organisms reproduce, or asexually-reproducing organisms divide, a copy of their genetic information is created, and occasionally the copying process is imperfect and a "copying mistake" occurs, whereby the copy is not identical to the original. This is known as a mutation, and such mutations are claimed by evolutionists to be the source of new genetic information. These mutations can be in the form of duplications, inversions, deletions, and translations of chromosomal material.

Although many mutations may be "neutral", i.e. they have no effect, in some cases the mutations may alter a physical (or psychological[Fact?]) characteristic. Many of these mutations are deleterious, but occasionally a mutation may introduce a characteristic that is beneficial. As these mutations may be passed on to offspring by inheritance, a new population of biological organisms with that mutation is potentially created. One population of offspring may therefore have different survival capacity than others, and the population with a greater survival capacity will prosper. It is this favouring of one population over the other which is known as natural selection.

Over long periods of time the theory says that the small changes occasioned by these processes can add up such that a creature alive today might be related to a very different creature that existed millions of years ago.

Information

As evolution progresses, minor changes or random mutations are said to produce new DNA containing new information, or instructions, describing how that creature will form. For example, the DNA of fish contains information for growing scales, fins, and eyes. However, it does not have the information for growing a lung, as does an amphibian. According to the "hopeful monster", or "punctuated equilibrium", idea, once every several million years, a fish will randomly be born with the DNA for some form of lung which natural selection will then work on. Supporters of more gradual evolution, such as Richard Dawkins, believe that new organs such as the lung evolve gradually over millions of years through myriads of transitional forms.

Whether gradually or suddenly, all this additional information must be created somehow. Evolutionary scientists believe that mutations and gene duplications supply this new information. No scientist has ever documented more than the rare disputed example of a mutation producing additional genetic information,[note 1] despite this needing to have occurred millions upon millions of times throughout the evolutionary history of life.

However, creationists argue that mutations essentially never supply new information. That is, no new genetic information—information for new organs, function, or processes—is ever introduced. The occasional beneficial mutations that occur are all actually losses of genetic information, but which in the right circumstances can be beneficial. An example is the loss of eyes in cave-dwelling fish: In total darkness their eyes are not only useless, but are potential sites of infection, so eyeless fish in dark caves have a survival value over fish with eyes. But this beneficial mutation is the result of the loss of genetic information for eyes; it is not a gain in genetic information, and cannot therefore explain where, for example, the information for eyes came from in the first place.

Falsifiability

Evolution is a form of origins science, and therefore has limited falsifiability. Falsifiability is often taken as a measure of whether or not a claim is scientific. That is, although some specific claims of evolution can be potentially shown to be false, the theory as a whole cannot be.

The problem for evolution is that the hypothesis is so flexible it can "explain" almost any observation. For example, Darwin expected evolution to happen slowly, with creatures very slowing changing form. Because of a lack of fossil evidence for this slow and gradual change, Stephen Jay Gould and Niles Eldridge proposed punctuated equilibrium, a version of evolution that says that change occurred in relatively quick spurts which left little evidence, separated by long periods of little change. Other scientists believe that both Darwin's and Gould and Eldridge's views have some validity, with the result that whether the evidence shows slow and gradual change, rapid bursts of change, or somewhere in between, evolution explains it. Thus it is impossible for observations about the rate of evolutionary change to falsify the hypothesis.

Another example concerns the existence of change at all. If change has occurred, this is said to be the result of evolution, specifically natural selection responding to environmental pressures. However, if no change has occurred, this is explained as the organisms being suited to their environment which, in these cases, has not changed.

There are many examples of organisms and organs being supposedly millions of years old but being essentially identical to organisms and organs existing today. For example, mammalian hair has supposedly not evolved in 100 million years.[10]

The hypothesis interprets the facts

Although most defenders of evolution will argue that they are just following the evidence, there are examples where this is not so.

Dinosaur blood vessels

For more information, see Dinosaur#Fossils.

Laboratory testing has shown that biological material will break down over time spans well under millions of years.[11] Yet when unfossilised soft tissue, including "pliable blood vessels", was found in T. Rex bones, rather than question how old they were, evolutionists marvelled at how long biological material can last. [12][13] or simply rejected the evidence. Discoverer Mary Schweitzer relates how a reviewer for a journal article about her evidence refused to believe it:

I had one reviewer tell me that he didn't care what the data said, he knew that what I was finding wasn't possible. I wrote back and said, 'Well, what data would convince you?' And he said, 'None.' [14]

Age of flowering plants

Amber was found in coal in Illinois that is claimed to be 320 million years old, 200 million years older than when flowering plants (angiosperms) are supposed to have evolved. Scientists analysed the amber and found that it had the chemistry of flowering plants. Rather than conclude that there is something wrong with the supposed ages, the scientists concluded that some other, unknown, plant that happened to evolve the same sort of amber 200 million years before flowering plants evolved the same thing.[15]

Evidence

For more information, see homology and transitional form.

Evolution is posited to have occurred over a period of the last 3,800 million years on Earth[16], which means that essentially all evolutionary change took place unobserved by mankind;[note 2] the theory has been developed around the findings in the fossil record, which is posited to contain remains belonging to many species that developed, thrived, and then became extinct long before mankind evolved.

Therefore, while some examples of changes in living things can be directly observed, the many changes required for the evolutionary "family tree" must be inferred for the evidence available today. Evidence advanced in support of evolution includes homology (similarities), both gross morphology (overall shape and appearance) and genetic, and the fossil record, both transitional forms and fossil distribution. Rigorous statistical testing of genetic sequences validates that universal common ancestry when it could have validated multiple origins of life.[1]

However, this evidence can be interpreted in more than one way. For example, evolutionary scientists interpret similarities as evidence of common ancestry, while creationists interpret similarities as evidence of a common Designer. Also, the expected finely graded sequence of transitional forms has not been found.

Because the changes that evolutionary scientists claim occurred, such as the change from invertebrates to vertebrates, from fish to amphibians, etc., all occurred in the past, evolution is not subject to the scientific method of observation, prediction, and repeatable testing.

Cultural effects

For more information, see Social consequences of evolution.

When Darwin published Origins, there was a widespread acceptance of the idea of a progression of humanity, and evolution was adopted by many as a mechanism of this progression.[17] The philosophers Herbert Spencer and Friedrich Nietzsche were influenced by Darwin's theory. Spencer, one of Darwin's main supporters, saw evolution as perpetual progress,[18] while Nietzsche drew on it for his idea of the übermensch, the next evolutionary step for humanity, bearing the same relation to humans as humans do to apes.

The idea of "survival of the fittest" was at the core of "social Darwinism" and was used to justify opposition to legislative measures aimed at ameliorating the lot of the poor and other weaker members of society. Concern about social Darwinism was at least partially responsible for William Jennings Bryan's active opposition to the teaching of evolutionary theory, including his participation in the Scopes trial.

In a review of Michael Ruse's book, The Evolution-Creation Struggle, Lael Weinberger says that the book "brings out the fact that the concept of 'progress' was important to many of these [early] evolutionists," and documents that these ideas about progress are still held in very high esteem by a great many evolutionists today; in fact, Weinberger says, "Evolutionists have a religion of progress, with evolutionary ethics to accompany it." However, these days, most mainstream evolutionary scientists have rejected the idea of evolution as progress.[19] Evolution is not, per se, said to be a procedure whereby organisms "progress" or "get more complex;" it is a process whereby those organisms that survive to produce more offspring have their genes more strongly represented in subsequent generations.

Evolution also prompted an increase in racism, provided a basis for Communism, and has led to many Christian moral values being discarded.

Evolution has also had an impact on the basis of laws. Laws in Western civilisation have traditionally been founded with the principle that there is a natural, or God-given, law, which is immutable and eternal. America was founded with this principle, as reflected in the statement in the Declaration of Independence that "all men are ... are endowed by their Creator with certain unalienable Rights". However, popularisation of evolution has led to a change whereby there is thought to be no such thing as transcendent morals, and laws can therefore be constantly changed and updated.[20]

Scientific consequences

As mentioned above, evolution is considered by its supporters as indispensable to biology. However, in a number of areas, evolution has been a hindrance to scientific research.

According to evolution, living things will be expected to have vestigial organs or other features, so when organs or other features are found without any apparent purpose, scientists have tended to treat them as useless rather than investigate their purpose.

Doctors have too-readily removed some organs in the mistaken belief that the organs were useless. Tonsils, appendixes, and even the coccyx (base of the spine) have been removed unnecessarily at times (although often there is good reason to remove them, and in the case of the former two, they function somewhat like "backup" systems, so can be removed if really necessary).[21][22]

Evolutionary theory also required the existence of so-called "junk" DNA, in order to solve a problem with mutation rates and to provide an area which could accept mutations without them being selected against.[23] So the 97% of the human genome that does not code for proteins was considered to be this "junk" DNA, and research into this part of the genome was given a low priority. However, it has since been found that a large portion of this "junk" DNA is not junk at all, but has purpose.

Researchers the world over are confirming that non-coding DNA holds critical clues to a vast range of diseases; breast cancer, HIV, Crohns disease, Alzheimer’s, heart disease, ovarian and skin cancer… the list is growing daily. A leading figure in world genetics, Prof. John Mattick, recently claimed that, "the failure to recognise the implications of the non-coding DNA will go down as the biggest mistake in the history of molecular biology" [24]

History

Origins

Evolutionary ideas have been around for thousands of years, but it was Jean-Baptiste Lamarck who first presented a concrete scientific theory, in his Philosophie Zoologique in 1809. Robert Chambers popularized the scientific debate, creating great controversy in Victorian England with his 1844 Vestiges of the Natural History of Creation. Charles Darwin, entering late into a divisive debate, introduced evolution based upon natural-selection in 1859 with On the Origin of Species.

Darwin sought to apply Charles Lyell's uniformitarianism to explain species. Though a Bible-believer in his youth, he grew convinced studying Lyell while voyaging on the Beagle, that "the Old Testament was incompatible with science, particularly uniformitarian geology."[25]

Some scholars believe the motives of those who promoted evolution was to replace God. Michael Ruse, believing that Christianity and evolution are compatible,[26] criticized those who used evolution as an ideological tool against Christianity by stating that for them, evolution is a religion in its own right, and further, that this is how it began: "Evolution ... came into being as a kind of secular ideology, an explicit substitute for Christianity."[27] Stephen Jay Gould agrees, saying that evolution is inherently materialistic and that this is what Darwin intended.[28]

Development

The evolutionary model has changed since Charles Darwin's time, particularly by incorporating genetics into the hypothesis. However, Darwin is still highly respected by evolutionists for his seminal work, and is still closely associated with current models of evolution. The journal Nature Cell Biology referred to evolution as "a theory that has survived essentially unchanged for 150 years"[29], and although acknowledging that Darwin knew nothing about genetics, Richard Dawkins said that "Everything we know about life, Darwin essentially explained." and that Darwin "got it astonishingly right. So you could almost say he nearly forecast digital genetics ..."[30]

Current scientific acceptance

Evolution has come to be the ruling paradigm of biology, and various scientists claim that biology cannot be done without evolution. For example, Theodosius Dobzhansky famously said that "nothing in biology makes sense except in the light of evolution". However, biology existed before evolution was accepted, and many biologists do their research quite well without accepting evolution. Even some non-creationists admit this. A.S. Wilkins wrote:

...most [biologists] can conduct their work quite happily without particular reference to evolutionary ideas. "Evolution" would appear to be the indispensible unifying idea and, at the same time, a highly superfluous one. [31]

Philip Skell agrees with Wilkins:

I recently asked more than 70 eminent researchers if they would have done their work differently if they had thought Darwin's theory was wrong. The responses were all the same: No. [32]

Popularity

For more information, see Support for creation and evolution.

Despite the dominance that evolution has in much of the mainstream media and the education systems, a significant number of people do not consider it to be correct. In the United States, polls have consistently shown that around 45 percent of people believe that God created humans. Polls in the United Kingdom and Australia showed greater acceptance of evolution, but with significant numbers still doubting it or not accepting it fully.

Suppression of dissent

For more information, see Suppression of dissent against evolution.

In several "first-world" countries, there is a very large degree of resistance on the part of academics and educators to allow the teaching of alternatives to evolution. Teachers, scientists, and others who have tried to teach alternatives (primarily intelligent design), or those who have tried to point out problems with evolution, or even those who have said that students should learn about alternatives, have reported dismissal, demotion, being barred from teaching, denial of tenure, and public ridicule. Students who indicate disbelief in evolution report threats of—and actual denial of—their qualifications.[33][34]

Evolution vs. the Bible

For more information, see Evolution and the Bible.

Evolution is incompatible with the Bible, and belief in evolution has numerous implications for belief in the Bible.

For example, the order of evolution and creation differ in numerous details, such as whether the Earth or the sun came first, whether or not reptiles came before birds, and whether or not land mammals came before marine mammals.

Both atheists and Christians have explained how evolution undermines the Bible's theology. Atheist Richard Bozarth wrote:

Christianity has fought, still fights, and will continue to fight science to the desperate end over evolution, because evolution destroys utterly and finally the very reason Jesus’ earthly life was supposedly made necessary. Destroy Adam and Eve and the original sin, and in the rubble you will find the sorry remains of the Son of God. If Jesus was not the redeemer who died for our sins, and this is what evolution means, then Christianity is nothing. [35]

Other atheists and evolutionists point out that evolution has implications for what we believe. For example, William Provine wrote:

Let me summarize my views on what modern evolutionary biology tells us loud and clear … There are no gods, no purposes, no goal-directed forces of any kind. There is no life after death. When I die, I am absolutely certain that I am going to be dead. That’s the end for me. There is no ultimate foundation for ethics, no ultimate meaning to life, and no free will for humans, either. [36]

Many people have related that evolutionary teaching has turned them from believing in God. Atheist Richard Dawkins, Australian playwright David Williamson, and evolutionary entomologist and sociobiologist E.O. Wilson are a few examples.

Sherwood Taylor wrote that "… I myself have little doubt that in England it was geology and the theory of evolution that changed us from a Christian to a pagan nation."[37]

See also

Notes

  1. ↑ Lenski has claimed to observe new genetic information being introduced to a population of E. Coli, but this is merely a reuse of existing information.[9]
  2. ↑ According to the evolutionary timescale, man has been around for approximately 0.0026% of the time since life began, and scientific observation has been around for approximately 0.00001% of the time since life began.

References

  1. ↑ 1.0 1.1 Theobold, Douglas L., A formal test of the theory of universal common ancestry, Nature 465:219-223 13 May 2010.
  2. ↑ For example, see Helena Curtis and N. Sue Barnes, Biology, 5th ed. 1989 Worth Publishers, p.974, cited by Moran, Laurence, What is Evolution? 22 January 1993 (The TalkOrigins Archive).
  3. ↑ Blyth, Edward, An Attempt to Classify the "Varieties" of Animals, with Observations on the Marked Seasonal and Other Changes Which Naturally Take Place in Various British Species, and Which Do Not Constitute Varieties, Magazine of Natural History 8(1) (1835): pp. 40-53.
  4. ↑ Theory on OneLook Dictionary Search.
  5. ↑ Hypothesis on OneLook Dictionary Search.
  6. ↑ Moran, Laurence, Evolution is a Fact and a Theory, 22 January 1993.
  7. ↑ Popper, Karl, "Unended Quest", Fontana-Collins, Glasgow, p. 151, 1976, quoted by Batten, Don, Don Batten, agricultural science, "In Six Days", Edited by Ashton, John.
  8. ↑ The American Biology Teacher 35:125–129, March 1973.
  9. ↑ Purdom, Georgia, A Poke in the Eye? Lenski and the adaptive acrobatics of E. coli, 30 June 2008.
  10. ↑ Doyle, Shaun, ‘Remarkable’ mammal hairs in amber?, 22 June 2010.
  11. ↑ Nielsen-Marsh, Christina, Biomolecules in fossil remains, The Biochemist June 2002, 12-14.
  12. ↑ Schweitzer M, Wittmeyer J, Horner J, Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present,Proceedings of the Royal Society of Biological Science, Volume 274, 22 January 2007
  13. ↑ Evan Ratliff, Origin of Species: How a T. Rex Femur Sparked a Scientific Smackdown Wired Magazine, 22 June 2009: "It was also the first-ever evidence that protein could survive even a million years, much less 68 million."
    Wilford, John Noble, T. Rex Fossil's Surprise: She Was Ovulating, The New York Times, 3 June 2005: "Among its rock-hard fossils, the scientists had already isolated soft tissues, including blood vessels and cells lining them - a most improbable discovery after 70 million years."
    Helen Fields Dinosaur Shocker, Smithsonian magazine, May 2006: "If particles of that one dinosaur were able to hang around for 65 million years, maybe the textbooks were wrong about fossilization."
  14. ↑ Barry Yeoman, Schweitzer's Dangerous Discovery, Discover 27(4):37–41, 77, April 2006.
  15. ↑ Oard, Michael, 320-million-year-old amber has flowering plant chemistry, Journal of Creation 24(2), p.16, August 2010.
  16. ↑ How did life start on this planet?, Natural Environment Research Council.
  17. ↑ Weeks, Noel, Darwin and the search for an evolutionary mechanism, Journal of Creation 12(3):305–311, December 1998
  18. ↑ Bergman, Jerry, Darwin’s critical influence on the ruthless extremes of capitalism Journal of Creation 16(2):105–109, August 2002
  19. ↑ Weinberger, Lael, Evolution as eschatology: A review of The Evolution-Creation Struggle by Michael Ruse, Journal of Creation 20(1), 2006, pp.31–33.
  20. ↑ Zimmermann, Augusto, Evolutionary legal theories—the impact of Darwinism on western conceptions of law, Journal of Creation 24(2), 108–116, August 2010.
  21. ↑ Lamb, Andrew, Human tails and fairy tales, 1 September 2007.
  22. ↑ Wilkinson, Richard, Cutting out a useless vestigial argument, Creation 26(3):51, June 2004.
  23. ↑ Carter, Robert, The slow, painful death of junk DNA, 9 June 2009.
  24. ↑ Genius of Junk, Catalyst, ABC Television 10 July 2003
  25. ↑ Michael Ruse, The Darwinian Revolution: Science Red in Tooth and Claw, 180.
  26. ↑ Ruse's book, Can a Darwinian Be a Christian?, is a defense of this idea.
  27. ↑ Ruse, M., How evolution became a religion: creationists correct? National Post, pp. B1,B3,B7 May 13, 2000, quoted in CMI, "Leading anti-creationist philosopher admits that evolution is a religion."
  28. ↑ Wieland, Carl, Darwin’s real message: have you missed it?, Creation 14(4):16–19, September 1992.
  29. ↑ Darwin's legacy, Nature Cell Biology 11, 111 (2009) (free registration required to read)
  30. ↑ Dawkins, Richard, Richard Dawkins on Charles Darwin, BBC News interview with Owen Bennett Jones, 14 February 2009.
  31. ↑ Wilkins, A.S., Evolutionary processes: a special issue, BioEssays 22:1051-1052, 2000, quoted by Creation Ministries International.
  32. ↑ Skell, Philip S., Why Do We Invoke Darwin?, The Scientist 29 August 2005, Online on the Discovery Institute web site.
  33. ↑ Expelled: No Intelligence Allowed, documentary film with Ben Stein, 2008
  34. ↑ Bergman, Jerry, Slaughter of the Dissidents, Leafcutter Press, 2008.
  35. ↑ G. Richard Bozarth, ‘The Meaning of Evolution’, American Atheist, p. 30. 20 September 1979.(Quoted on the Creation Ministries International web-site)
  36. ↑ Provine, W.B., Origins Research 16(1), p.9, 1994.(Quoted on the Creation Ministries International web-site.)
  37. ↑ Taylor, Sherwood F., ‘Geology changes the outlook’, in Ideas and Beliefs of the Victorians, Sylvan Press Ltd, London, p. 195, 1949, quoted by Batten, Don, U.S. News and World Report joins in the evolution onslaught.

Further reading

Creationary viewpoint

Evolutionary viewpont

  • Understanding Evolution, by University of California, Berkeley, is a simple and clear presentation of what evolutionists believe.
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