26 May 2023

Missing links are a myth, but whose? Chapter 4 of From Extraterrestrials to Animal Minds

There are some truly vexing and annoying myths of evolution. They are almost exclusively recited and embellished by religious propagandists, some of whom actually know what they're doing. Rarely but notably, there are myths that are gleefully repeated by creationists while being amplified by scientists who should know better. The clearest example of this is the mythology and nonsense surrounding "junk DNA."

Missing links are not an example of this.

The phrase "missing link" is so dated and so scientifically laughable that it could only be seriously discussed in a book about myths that circulate among laypeople who watch YouTube videos about Sasquatch, refuse vaccines to own the libs, and go to church. What is it doing in a book by Simon Conway Morris, a book that claims to address "areas of received wisdom that are long overdue for careful reexamination"? It's the subject of the fourth chapter of From Extraterrestrials to Animal Minds: Six Myths of Evolution, "The Myth of Missing Links."

The Mórrígan. A myth.
This question summarizes one source of my deep disappointment in this book, a work that has lowered my opinion of its author. I have no right to blame my disappointment on the author, and I know that my feelings betray an expectation on my part that the professor has no obligation to even consider. That expectation: that Christian scientists acknowledge and consider resisting the mountains of lies that their fellow believers dump into the world. I expect to introspect and learn about this frustration of mine when I get to Complicit by Max Bazerman. For now, I think it's only fair to confess that this chapter pissed me off not because it's wrong about "missing links" but because it suggests that there is a myth of missing links among the people who Conway Morris used to call colleagues: biologists. It's a myth all rightbut it's someone else's.

If we were to move this chapter to a book it seems Simon Conway Morris will never write, about Facebook crap that Christians feast on, it would be a pretty good exploration of two concepts that don't fit into the old fables about ladders of progress:

1) Natural history is the unfolding of a tree, and not the ascending of a ladder. Even big events like the emergence of tetrapods from fish, or the invention of feathers, are characterized by parallel innovations in lineages that have accumulated tools and ingredients. Here's the author actually naming the myth:

This is the myth of a missing link: long before the final breakthrough, the seeds of success were not only being sown, but multiple times. (p. 117)

This alone makes the metaphor of a "missing link" nonsensical.

2) Organisms are often "mosaics" of features that are "advanced" and "primitive." This is true today and it was true hundreds of millions of years ago. As Conway Morris writes about the era of "fishapods":

Although the overall story of tetrapodization is clear enough, in detail the story is very far from some sort of monotonic narrative. This is because the fossils in question are almost always a puzzling muddle of characters, revealing a striking degree of mosaic evolution. In other words, in any given species we see relatively archaic features co-occurring with more advanced ones. (p. 114)

These two concepts are interesting, and Conway Morris takes us on a tour of convergence and parallel evolution with moderate panache. He ends with H. sapiens and family, with little to add conceptually but with an increasing frequency of interjections about "the numinous" and other themes that form the obvious goal of the book. Myths, I assure you, are not the topic.



Image credit: Detail of Battle Crow from "Cú Chulainn riding his chariot into battle" by Joseph Christian Leyendecker. From Wikipedia.

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