The Language of God: Micro vs. Macro

The Language of God, Chapter 5

By B.J. Marshall

Before tackling the gritty details using DNA evidence to support human evolution, Collins addresses Darwin, mutations, and the “rather arbitrary” distinction between microevolution (“incremental changes within a species”) and macroevolution (“major changes in species”) (p.131-2). In my discussions with Creationists, the micro- v. macro-evolution thing always comes up. So I was pretty excited to see how Collins would cover this topic.

He does a fairly decent job mentioning how we’ve seen lots of changes within species, such as finch beaks changing shape over time. He also discusses saltwater v. freshwater sticklebacks and rapid variation in viruses. He even brings stickleback evolution into a DNA setting by stating that the specific gene – EDA – has repeatedly and independently appeared in freshwater, resulting in sticklebacks losing their plates. Oh, but it gets better, because humans also have an EDA gene, and “spontaneous mutations in that gene result in defects in hair, teeth, sweat glands, and bone” (p.132). So, Collins adds as he tries to connect sticklebacks to humans, it’s not tough to see how the differences between sticklebacks could be extended; “larger changes that result in new species are a result of a succession of smaller incremental steps” (p.132). And that’s fine for highlighting “microevolution,” which is something Creationists can believe anyway. And it’s even good for alluding to macroevolution given his “succession of smaller incremental steps.” But he only ever leaves it at the hypothetical.

He does his readers a disservice when he claims “we haven’t seen new species arise” without expanding on what speciation is (p. 132). Additionally, he leaves the door open to Creationists by saying macroevolution only consists of “major changes” in species. Speciation is kind of a vague line but is usually delimited by two species’ ability to interbreed; they usually can’t or, if they do, their male offspring are sterile. And the fact is that we have observed speciation in a number of instances. One example is in polyploidy organisms that contain a multiple or combination of complete genomes; these usually result in new organisms that, due to the number of chromosomes, can’t reproduce with their originating species. It’s called allopolyploidy if genome duplication happens through crossing two different species. Another way speciation can occur is through sexual isolation, such as in ring species such as the Ensatina eschscholtzi salamander.

But, regardless of whether we’ve observed speciation, Collins gives Creationists a foothold by leaving it up to interpretting what constitutes “major changes” in species. For example, perhaps the inability to breed isn’t too bad, because all those salamanders still look very salamandery. It’s not like you get a crocodile and a duck together!

Other posts in this series:

About Adam Lee

Adam Lee is an atheist writer and speaker living in New York City. His new novel, Broken Ring, is available in paperback and e-book. Read his full bio, or follow him on Twitter.

  • http://www.facepunch.com/member.php?u=298989 Jeep-Eep

    The subway mozzie would like a word with Collins-and maybe some blood too, for good measure.

  • jack

    BJ,

    Excellent post, and I loved the salamander example. It beautifully illustrates the principle that all change in evolution happens through small steps, each of which must be favored by natural selection. The crocodile and the duck did, of course, have a common ancestor, and the creationists love to insist that this implies the existence of something as absurd as the crocoduck to which you linked. In reality that ancestor was a primitive triassic reptile that didn’t look much like a duck or a crocodile. When two subpopulations of this species diverged to the point where they first became the two distinct progenitor species that led to crocodiles and ducks, they looked about as different from each other as do the two newly formed species of salamanders in the video. It took a long time, and many more speciation events, to get from there to crocodiles and ducks.

  • http://uzzas.blogspot.com/ Uzza

    No mention of ring species? No thoughts on how many pairs of Herring Gulls Noah had on his ark?

  • kennypo65

    The anti-evolution crowd are only worth my time when they try to teach their religion in public school, otherwise, they are just IDiots. They say,”I don’t believe in evolution.” I say, “Somethings are true whether you believe it or not.” which is the same chestnut they use when I profess my atheism.

  • BJ Marshall

    @kennypo65:

    Saying “some things are true whether or not you believe them” pretty much kills the conversation; if killing the conversation is your goal, then that’s perfect.

    I try to use anti-evolution people as practice. I try to use different tactics to see if I can understand why they believe something and see if I can persuade them. Some tactics work better than others; in the end, I might learn how to engage in these conversations more effectively.

    It’s really hard because it only takes them two seconds to blurt out baseless nonsense but takes several minutes to dismantle the nonsense get to the facts. When the stupid starts to burn too much, it’s time to end the conversation.

  • jack

    BJ,

    You have the patience of the proverbial saint. I find it really difficult to try to engage these folks in meaningful conversation, because most of them don’t believe in Creationism as a result of poor reasoning (although their reasoning is certainly poor). They believe in it because they have a comforting, if illusory, personal relationship with an invisible god. The Creationism, and all the silly rationalizations that go with it, come after the fact.

    Every once in a while you may encounter a creationist with enough integrity to face the reality of evolution with courage when you explain it. Sadly, most don’t, in part because evolution is such a counter-intuitive subject, but mainly because of that emotional commitment.

    I’m just curious: have you had any successes? By that I mean, have you been able to persuade any of them that evolution is true (even if they still retain their theistic belief)?

  • BJ Marshall

    My own deconversion was a slow and steady chipping away at the edifices of a religious belief I was happy and comfortable with. Even given that creationism/evolution might not be as great a divide as theism/atheism, I don’t think I have any delusions of single-handedly showing people the light of reason and leading people to reject their beliefs after a few short encounters.

    I honestly don’t know whether I’ve had any successes in changing their minds. Certainly none of them have come right away to agree with me, and I haven’t followed up with them. (One ardent Creationist was a neighbor of our friends, but then our friends moved so I don’t see the Creationist anymore.) If I’ve at least planted a seed of doubt in their heads, then I think that’s some modicum of success.

    I’ve had more success in seeing those Creationists clam right up after something I said. For example, hitting them with a barrage of examples of transitional fossils only seems to confuse them. And they can always hide under the “yeah, I get microevolution” excuse.

  • Jim Baerg

    I think it’s unreasonable to expect anyone to change a belief *solely* from one conversation.

    If someone came up with arguments & evidence against some (major) belief I held, it would take a minimum of days checking for holes in the arguments & confirming the evidence before I would be *convinced* I had been wrong rather than merely having some doubts I didn’t have before.