Evidence for Macroevolution

On Facebook recently, my brother asked why, if “macroevolution” is real, there aren’t more variety “in between” the species that exist today. I thought the answer to that question might be worth posting here.

The context of the question, was as comments to a tweet in which I thanked Richard Dawkins, citing his The Selfish Gene and The Ancestors Tales as having been instrumental in my scientific re-education, coming from a creationist homeschooler’s background (which my brother shares).

Among other things, all those in-between species did exist, and we’ve found scads and scads and scads of their fossiles. Most didn’t survive to today (except as fossils), because they were far less fit to compete with both descendents and cousins who were much better suited to their respective environments than today. Evolutionary jumps tend to happen when something in the environment or situation changes in a way that effects survival rates. This tends to provide strong death rates in the members that are poorly suited to deal with the change, providing a huge opportunity for members who are even just slightly better-suited to reproduce exponentially. Every small variation that is introduced that provides any sort of benefit in the new environment, reproduces quickly, because of its usefulness.

But the biggest evidence is in our genes. Every important variation introduced in a species, is genetically present in that species’ ancestors, written much the same way as in the original (minor variations obviously happen, but they bear the clear vesitages of the original genetic code). Sometimes, these features disappear, eradicated to make way for other more important features; but when these features actually disappear, and don’t transform into other ones, the genetic code for the abandoned feature still exists in the descendants’ DNA – either no longer activated to produce proteins, or subdued through variation or other genes, so that the effects they produce are just “quirks”, not particularly useful nor harmful. There are plenty of cases where retro-viruses (viruses which operate by implanting themselves in a cell’s DNA strands) were absorbed into reproductive cells, and deactivated. Those viruses are then passed on to that organism’s descendents (all in the same relative location), which adds very concrete proof that a set of species (often very diverse species) share an ancestor. Human beings, ourselves, carry such viruses as obtained from ancestors we share with chimps and other apes. It’s “garbage” DNA code, that’s inactive and has no effect, and corresponds to a known retro-virus that still exists in the wild. If it were activated, its effect would be the death of the host.

Another thing that tells us of our common heritage with the chimp, aside from the fact that 98% of our DNA is identical to that of a chimp, is that the reason we have one fewer chromosomes than chimp DNA, is that two of the chromosomes present in the chimp, are fused to form one chromosome in us. All the same basic code structure is there, but the “chromosome separation marker” got glitched into uselessness, resulting in just a single chromosome where two existed previously.

Random variation tends to be detremental far more often than progressive (usually just resulting in spontaneous abortion, or else a single organism, or a short-lived family, that doesn’t survive or reproduce well in comparison with its cousins), and even the ones that are progressive, are usually tempered with severe drawbacks that undermine survival only _slightly_ less than they improve it. This leads to a pretty volatile state, where every tiny variation that helps improve that instability even a little bit, tends to spread very quickly due to the significant improvement in survival. This tends to lead to what’s basically evolutionary “jumps” between islands of stability, because the species that were introduced in-between those islands died off much more quickly than their more-stable cousins. But we still have proof that those instable in-betweeners existed, due to a truly dizzying array of discovered fossils.

We’re a series of patches, and our biology attests to that. We have far too many flaws built into us to be the work of a perfect designer – the worst of them are simply balanced away by a large array of other patches. One big patch occurs that improves our survival (but introduces other problems), and is usually quickly followed upon by progressively smaller adjustments that help even out the problems produced by earlier “solutions”. Evolutionary jumps start out very, very ugly, but are quickly (in geological terms) smoothed out by additional “hacks” that help us function better.

Aside from Dawkins, an even more important push away from a lot of my creationist misinformation, is this Index to Creationist Claims (and rebuttals).

7 thoughts on “Evidence for Macroevolution

  1. Chris

    I think you make a pretty good case, but you jump to a conclusion with which I (obviously) disagree:

    “We have far too many flaws built into us to be the work of a perfect designer.”

    Unlike many Christians, I don’t personally believe that evolution negates the existence of a creator. And, unlike your assertion, I don’t believe that an imperfect creation (or creation process) negates the existence of a perfect designer. Putting aside the debate between evolution and creationism, a major theme in the Bible is the concept of God using imperfect people and situations to accomplish his perfect plan. Evolution could simply be viewed as another example of this characteristic of God.

    A friend of mine (both a staunch evolutionist and dedicated Christian) once offered this observation: “Most things God does evolve.”
    I find it hard to disagree. The Bible is essentially the story of people gradually understanding and evolving in their relationships with God. The spiritual journey of a follower of Christ evolves in the same way, and really few things in life arrive without some amount of progression and development.

  2. Micah Post author

    Thanks Chris! That’s an interesting line of thought. Allow me to clarify my assertion to:

    “We have far too many flaws built into us to be (or to once have been, given that they’re fundamental to our ‘design’) the finished work of a perfect designer.”

    But I might question whether it’s reasonable to think that such a being could ever expect to reach a “finished” state through a series of increasingly finer patches, as opposed to merely a “good enough for government work” state. Either way, it strikes me more as human-like bumbling (as we in fact do operate this way for pretty much everything), than something according to an overall plan, unchanged since its inception, meant to lead to eventual perfection.

    And there’s a question, too, as to why someone would choose to plan to do things in such a way, if they could instead simply build it perfect from the beginning. In the case of relationships, I could certainly see how you could argue that it’s better that way; but when it comes to biological functions, it strikes me as strange behavior for an omnipotent, omniresourceful, perfect creator, especially one that cares infinitely for the well-being of his creatures.

  3. Chris

    To your first point: I suppose the most obvious answer is that we’re not a finished work. Speaking Biblically, this is true in terms of receiving perfected bodies in the life that follows. Speaking in accordance with evolution, we are still evolving, which is a concept that does not necessarily disagree with Christianity (though I doubt either of us believe perfection will be reached on this plane).

    When it comes to WHY God allows imperfections in His creations, or seems to prefer using imperfect things to get things done, that’s one of those questions that, even when answered, could still be followed with several more “why” questions. As a Christian, I believe that this life is like a vapor compared to what is waiting after, so when I see limitations or “flaws,” I see them as temporary. This, combined with the fact that some of the most inspiring people and advancements come as a result of flaws and suffering, leads me to understand that while, yes, God cares, that does not mean that He must intervene in every area or make everything biologically perfect, flawless or painless in order to meet our standards for a benevolent Creator.

    I think it does mean that He’ll forgive me for that last run-on sentence.

  4. Micah Post author

    Heh, I’m actually planning on updating the entire “About Me” section in the very near future, and other updates as needed. This blog has been languishing for a very long time, basically ever since I started microblogging via Facebook and Twitter and such. It seems to fill most of the needs for which this blog was originally created. I’m currently planning on revamping this site to be more of an “intro to Micah Cowan” for people (new friends, acquaintances, etc) who are interested in learning more about who I am, and making the important highlights more prominent. I’ll probably also continue to make occasional blogs here, especially if it’s a thought I want to hold onto, but the primary focus will probably change.

    This is a fun conversation. I hope we’ll have more. 🙂 I always enjoy talking with you, regardless of whether we agree, because unlike 99% or more of the people I meet (regardless of creed), your opinions are generally the result of things you’ve actually thought about, as opposed to parroting. This makes you a uniquely interesting person to converse with. 🙂

  5. Chris

    Thanks, Micah. I appreciate the compliment, and the feeling is mutual. I think we both know too well that it’s a common occurrence for people to accept something as truth simply because it suits one’s predetermined views. I know you’ve put a lot of thought into what you say, as well.

    Thanks again for madcowan.com. I’m still setting it up, but it’s starting to look like… something… 🙂

  6. Chris

    As I’ve mentioned, I have a friend who is firmly in both the evolutionist and Christ-following camps. I mentioned our discussion to him. Since he has given this topic much more thought and energy than I have, I’m always interested in his perspective on this sort of thing. FWIW, he’s one of the most intellectual people I know and a member of MENSA. I think what he had to say was what I was thinking, but more aptly said:

    I would agree with what both you and your brother said.

    My arguments for evolution are scientific. I think the evidence for evolution is just too overwhelming to deny. Once I acknowledge that as what I see and believe, then I don’t let the consequences of my belief influence me. If I don’t like the consequences, then too bad for me. What’s true is true, regardless of consequences. I judge what’s true by the evidence, not the results.

    My belief in God is based on both evidence I see in history and around me and on my experience. Actually, it would be more accurate to say that my belief in Jesus is based on those things. My belief in God is based mainly on my own experience, and my idea of who God is comes from what Jesus said.

    When I acknowledge that God uses flaws and the principles of evolution–such as that suffering leads to growth and death to advancement in life–I am arguing that my belief in evolution and my belief in God as Creator do not conflict. I am not arguing for evolution or for God; I am arguing that the two are compatible.

    So your brother’s statement I see as an argument for evolution. We have far too many flaws to simply be the finished work of a perfect Designer.

    I see your statement as an argument for belief in a perfect Creator God who chose not to use a perfect design. You are giving reasons that a Designer, who is perfect and thus could have produced a human that was perfectly designed, might not have done so. Your argument is thus an argument for compatibility between a perfect Creator God and evolution.

    And I see both arguments as true. I don’t think your brother’s argument for evolution succeeds as an argument against a Designer. It’s an argument against a perfect design in humans. Humans are not perfectly designed. We evolved, and we have a lot of flaws as a result of evolution. It’s just like programming. You can build a perfect program if you’re good enough, but a lot of programs start small, and then they are added to. Such programs have a lot of flaws.

    God may have had many reasons for producing us through a step upon step approach rather than handcrafting a perfect product. I think the ones you suggested here are valid.

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