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Evidence of Common Descent in Evolution

In a discussion on transitional forms in evolutionary biology, creationist Paul Glenn Cawley declares that there is no evidence that living organisms share common descent:

“Those who adhere to the evolutionary theory act like it’s been proven that all life “descended” from common ancestors when in fact it has NOT been proven! The best biology has proven is that living forms VARY within their own kind.”

This is not true.  The following are links to lines of evidence for the common descent of life of which I’m aware:

  • All living things share the same structure of genetic code for DNA, RNA and the reading of DNA and RNA to create proteins (read: Cassandra’s Tears; Darwin Was Right). Recently, scientists have created an living, reproducing artificial organism with different nucleotides than used in nature (read: Nick Statt).  This indicates that the nucleotides being used aren’t the only possible ones; and yet all living things do share the same basic code, indicating shared origins.
  • The similarity of two organisms’ genomes is strongly correlated with the length of time since the point in the fossil record at which the two organisms diverged (read: National Center for Biotechnology Information).
  • Organisms that appear to be more related according to other lines of evidence (such as fossil records of transitional forms and phenotypic similarity) also have functional proteins that are more similar to one another (read: Carl Zimmer, Douglas TheobaldCassandra’s Tears).  Organisms that are more distantly related according to the fossil record and phenotype share less similarity in the makeup of the proteins that regulate their biology.
  • The more closely related two organisms appear to be according to other lines of evidence, the greater the similarity in their shared set of non-coding genes and endogenized viral code (virus DNA incorporated into a host’s DNA) — two markers of shared history of inheritence that are passed down (read: Cassandra’s Tears, Douglas Theobald, Phylointelligence).
  • Chromosome changes– the correlation of chromosome number, type and structure (including the migration of centromeres and chromosome fusion) with other indicators of common descent (read: Discover magazine, Alec MacAndrew, Phylointelligence).
  • Vestigial organs are present in distributions that match transitional forms in the fossil record (read: Cassandra’s Tears).
  • Non-expressed genes for features shared by ancestors (teeth in birds, gill slits in humans) can be found in organisms’ genomes (read: Cassandra’s Tears, University of Montana).
  • Differences within and across classes, orders and families are greater across longer spans of time and longer spans of geographic space (read: Cassandra’s Tears, University of Montana, University of California at Berkeley).
  • The discovery of large numbers of transitional forms between different classes, orders and families (read: RationalWiki,, Smithsonian Institution, Robin Lloyd, University of California at Berkeley, Douglas Theobald).
  • The same island species are not spread uniformly across similar islands around the globe; rather, they are limited to islands that are close to one another (read: University of Montana, University of California at Berkeley).

If you’re aware of other web-available resources documenting additional lines of evidence for common descent of Earth’s living organisms, or enriching the lines already listed above, please add a comment and I’ll be glad to update this list.  Thanks!




10 thoughts on “Evidence of Common Descent in Evolution”

  1. Paul Glenn Cawley says:

    Just because living forms share similarities in their substance or form does NOT prove “common descent” but could also be because they were made by a genius engineer who used the same common materials and design features for each of them. Furthermore, scientists still understand very little about morphology and are currently in a vast study of the subject called Epigenetics…referred to by Mark in another reply here to Ella. Btw: here is John Thomas’ initial response (I posted your comments on my Facebook page Group The Genesis Gap Doctrine group: here is what John initially said (and I’ll drop in his final thought as another reply) :
    John Thomas
    Hi Paul, Evolutionists like to discuss what might be called ‘twigs’, not realising that Darwin’s whole ‘tree of life’ has now been felled by the Human Genome Project. In answer to the evolutionist I would quote top Harvard evolutionist Prof Richard Lewontin who says: ”Our ignorance of the generation of shape remains profound’. In another place (‘It Ain’t Necessarily So’) he admits: ‘We do not have the faintest idea about how all this (i.e. genes, DNA) is turned into the shape of my nose’. The fact is that evolution has hit the buffers. It is not ‘all in the genes’, hence the call for a new ‘epi-genetic’ project.The simple fact is that the genes do not contain the blueprints of any organisms. No wonder Sheldrake is reviving the old idea that organisms are shaped by a non-physical ‘morphic field’ that science knows nothing about and cannot investigate. Sadly, those who have nibbled the magic mushreoom of Darwinism, find it hard to cope with reality. Sorry to waffle on, but I really believe that the game is up. They reached the end of the evolutionary rainbow and there was nothing there. For more waffle, see my little book ‘Literal Genesis’. (Free PDF at uk). I will take a look at the link you cite, which I notice dates from 1991. Lewontin’s stuff is newer than that.
    Edited · Unlike · 2 · More · Aug 2

    1. Mark says:

      Just because a “top Harvard evolutionist” said “our ignorance remains profound” and “we do not have the faintest idea about how all this (i.e. genes, DNA) is turned into the shape of my nose” does not mean that the theory of evolution should be thrown out. I would virtually guarantee that Richard Lewontin does not think that our lack of understanding of all evolutionary and biological processes in any way disproves the Theory of Evolution. Until evidence emerges that conflicts with the Theory of Evolution scientists will continue to accept it as the best theory we have and work with it.

      The problem with using “Gap Doctrine” or “Intelligent Design” is that they (as supposed theories) do nothing to advance our understanding of the natural word. They do not make predictions for future events nor do they provide any framework for understanding what we have observed. They are not testable. That is the single most damning aspect of these ideas. A scientific idea, especially a theory, must be testable. They are simply hand waving dismissals of what we don’t (yet) understand and supposing that we will never understand certain aspects of the natural world. They are weak ideas merely supposing that if scientists don’t understand a process “it must be God”. At the worst, they stifle future scientific inquiry because they presume to have an answer that cannot be tested or investigated further.

  2. Paul Glenn Cawley says:

    Here is John’s next comment:
    John Thomas
    Hi Paul, I have read the post from Jim Cook.The point is, people believe what they want to believe – like British biologist Derek Hough who realised on the way to work one morning that Darwin’s mechanism for evolution was infantile nonsense. But he remains an evolutionist – and like all those researchers Cook cites, is desperately looking for a more credible explanation. Cook, as he cheerfully admits, cannot answer the basic questions I posed. But he is happy with that because he has nibbled the magic mushroom and seems to be in a state of evolutionary euphoria. As regards your own feeling, I would advise that you stop wasting your valuable time and emotional energy discussing stuff with individuals, who in my experience, can get quite unpleasant. Best regards,

    1. J Clifford says:

      Paul, the science of biological evolution isn’t just about Darwin. It hasn’t been for over 150 years. Scientists don’t hold Darwin’s books to be holy or without flaw in the way that Biblical literalists revere their Bible. The point of science is to keep on building better models by correcting past errors – something Creationists refuse to do when confronted with the huge number of flaws in their pseudoscientific models, full of leaps of faith and untestable claims.

      1. Paul Glenn Cawley says:

        Perhaps that is true of Young Earth Creationist scientists like Ken Hamm or Hovind but we Old Earth Creationists accept MUCH of mainstream science, and because of this you have a real problem trying to label us holding to “pseudoscientific models full leaps of faith and untestable claims” when you are guilty of the very same things. We reject MOST of the “science” of the YEC movement as BAD science too but believe the Gap Principal of Genesis recognizes the science of an Old Earth and the Geologic and Astrophysic models (and other sciences) that come with that view,

        1. J Clifford says:

          Paul, the key here is that Old Earth Creationists accept MUCH of mainstream science, but also reject MUCH of it out of hand simply because it conflicts with your religious beliefs. Your beliefs about reality are still at root religious. You choose what to believe based upon what is written in the Bible and taught in churches.

          As Steven Dill, leading of the proponent of the Gap Theory of Creation explains his own book, “The basic assumption of the author is that God is smart enough and powerful enough and sovereign enough to make His Works and His Words agree.”

          The base assumption of the Gap Theory of Creation is that there is a divinity called God who created the world, and that for that reason, the words of the Bible and what we see in the world must be in sync. Everything else in the Gap Theory of Creation flows from that religious presumption. That’s what makes the Gap Theory of Creation not a theory at all, but just another theology.

          Call it a theology, please. It’s not a science.

    2. Jim Cook says:

      Interesting that he wants to make it personal. He can insult me all he likes, because I’m not the point. The point is that there are multiple and robust lines of evidence for common descent in evolution.

    3. Mark says:

      There are two types of “belief”: theological and rational.

      In religion and theology “belief” is the foundation of everything else. It forms the foundation of all understanding. It cannot be proved. It cannot be doubted. It is accepted as true often in the face of conflicting information. People believe things solely because they want to believe. No amount of evidence or information will change their belief. In fact, contradictory evidence is often dismissed because it would disrupt the foundational belief upon which a person’s entire understanding stands. Questioning or discarding this type of foundational belief can be psychologically traumatic. People will go to great extents to avoid questioning these beliefs.

      In rational thought belief comes only after a long process of observation and collection of facts. Rational belief can change when new observations and facts contradict the original belief. People believe things because they have been shown time and again to be true and nothing has been discovered to prove their belief false.

      Scientists “believe” in the Theory of Evolution because they have seen mountains of evidence supporting it. All your links and statements are really nothing more than minor ideas that only provide questions into which more research needs to be conducted. I’m sure they have all been fully examined by the scientific community. If any of them truly discredited the Theory of Evolution the theory would have been quickly discarded by the scientific community. Until a better Scientific Theory comes along, Evolution is the one we continue to work with. To date, the other ideas you propose don’t even come close to measuring up to Evolutionary Theory. The Gap Principle of Genesis is one of those ideas sorely lacking in any scientific merit.

  3. Paul Glenn Cawley says:

    Jim my last name is not Crowley; its “Cawley”

    1. Jim Cook says:


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