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History, Evolution, and The Darwin Debate

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Embryological dissent: from von Baer to Lovtrup

February 25th, 2008 · No Comments

Karl Ernst Ritter von Baer, Edler von Huthorn (1792-1876).
Myers’ account is smothering von Baer, damnation with (faint) praise.
The early embryologists had a hard time embracing Darwin because they saw that his theory wouldn’t work.
The tradition of embryologists dissenting in the underground includes the more recent Soren Lovtrup, and his
classic Darwinism: Refutation of a Myth.

He was an Estonian — and seriously, the Baltic states don’t get enough credit as a major seat of European civilization, one that has been walked over far too many times. Let’s all hear it for Estonia and the scientific tradition therein!

As you might guess from the name, he was also a Prussian nobleman, a genuine, certified knight. Hereditary titles don’t mean squat as far as the value of his work goes, but still, there’s a cachet to being a member of the old European nobility, especially the cranky, distinguished branch rather than one of the numerous fluffy superficial branches of hereditary twithood.

He volunteered for the Napoleonic Wars, another distinction not often bandied about in the pantheon of scientists. Better yet, he was on the right side, opposing Napoleon’s invasion in 1812. Best of all, he didn’t fight — he served as a doctor. You’ve got to respect that.

He was a developmental biologist who discovered the blastula stage, the notochord, the mammalian ovum, and with others, defined the germ layer theory of development, which explained the configuration of the blastula and gastrula as layers of cells in sheets. This is all stuff that is so basic and so central to our knowledge of embryology that we simply take it for granted nowadays.

He wasn’t just an embryologist, but also a taxonomist, entomologist, ichthyologist, anthropologist, geologist, ecologist (before the word was coined), geographer, and arctic explorer. Those were the days, when good scientists were expected to know something about just about everything.

He was an opinionated curmudgeon who didn’t hesitate to argue with the scientific establishment of his day. He disagreed strongly with the Naturphilosophen who argued for a systematic hierarchy in the taxonomy of life with an attendant echo of that pattern in developmental recapitulation. He proposed his four laws of development to explain development as a divergence into diverse forms, rather than an adherence to a historical pattern. Here they are:

General characters appear earlier in development than specialized characters.
Less general character appear later (and build on) the general framework of earlier stages.
The embryo of any organism, rather than passing through the stages of other forms, tends to progressively differentiate itself from them.
The embryo of one animal form never resembles the adult of another, but only its embryo.
Good rules, and still valid.

Late in life, he argued equally strongly against Charles Darwin’s theory, even while accepting the evidence Darwin discussed. His last book, Studien auf dem Gebiete der Naturwissenschaften, contained a critique of evolutionary theory that said that “for a true understanding of nature, we cannot dispense with a governing intelligence,” and he also compared life to a machine which builds itself, and a chemical laboratory that assembles its own reagents — that’s right, he was a creationist, and one of the Intelligent Design variety. Except, of course, that he relied on the competent interpretation of the actual evidence of his day, rather than the New Creationist strategy of promulgating ignorance. His thinking was guided in part by his belief in an archetype for each species, an ideal pattern from which only limited deviation could occur.

Despite his bona fides as a respected opponent of evolution, modern creationists ignore him for the most part. Why? I think because he also said this, upon examining some unlabeled embryo specimens:

I am quite unable to say to what class they belong. They may be lizards, or small birds, or very young mammalia, so complete is the similarity in the mode of formation of the head and trunk in these animals. The extremities are still absent, but even if they had existed in the earliest stage of the development we should learn nothing, because all arise from the same fundamental form.

The similarity of early embryos is something the creationists want to deny, so the fact that an unimpeachable anti-evolutionist was the first to describe the similarities in detail must make them rather uncomfortable. They try to pin the observation on Haeckel, instead, and call it a “forgery.”

By the way, the other current creationist copout, that various embryos do differ substantially at the very earliest stages, doesn’t apply either. Karl Ernst von Baer discovered the blastula stage, and also described the earliest embryonic membranes. He was well aware of the early differences.

Tags: Evolution

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