THE TREE OF LIFE is a model illustrating the relationships between species. It reveals the common descent of life on earth. It’s like a jigsaw puzzle with millions of pieces, both fossils and living species. After diligent research by generations of scientists — not only biologists, but scientists from separate disciplines like geology, paleontology, organic chemistry, astronomy, and nuclear physics (for radiometric dating techniques) — the pieces all fit. They lock into place in several independently cross-confirming ways, including form, function, chronology, and molecular biochemistry.
When jigsaw puzzles are properly assembled, a picture emerges; with data, a scientific theory emerges. In this case, what emerges is the theory of evolution. There are still some missing pieces, and there probably always will be, but the evidence now assembled is more than sufficient to reveal the picture. There is so much evidence that at this point, the picture itself can confidently be used as a guide for predicting the fit of new pieces that are found. When they are put in place, DNA evidence (when available) shows a close, pre-existing relationship of the pieces that we’ve fitted together, thus confirming the picture. Any re-arrangement of the pieces would be inconsistent with such evidence.
Other well-established theories function similarly. A theory emerges from the data, and then the theory predicts additional data. For example, after decades of matching stellar distances (determined by Cepheid variables) with the redshift of their images, the redshift alone is now used as a reliable guide to distance — subject to verification whenever a Cepheid variable is available, and the two independent lines of evidence have always confirmed one another.
Creationists are forever claiming that the evolutionary picture revealed by the evidentiary jigsaw puzzle is nothing more than the arbitrary result of our materialistic prejudices, and that by using different presuppositions the puzzle’s pieces could be assembled some other way — presumably the new arrangement would show their own preferred picture. So why don’t they ever do it? Well, they do have a model, so to speak. It’s based on the concept of “kinds,” and Noah’s Ark, and the global Flood. But the creationist model isn’t supported by any verifiable evidence — indeed, it was discredited by geologists before Darwin’s time — so in the context of science it’s appropriate to ignore it.
Instead of actually doing research to support their model, creationists always change the subject away from their embarrassing lack of evidence and ask: “Where are the transitional fossils?” When presented with a truckload of them, they claim that they’re all fakes, or they sometimes retreat to a fallback position: “Why don’t you have more transitional fossils?” We find more every year, but somehow it’s never enough for the creationists. No matter how many more are found, there will never be enough. Creationists are the OJ jury, for whom no amount of evidence will suffice to overturn their faith-based bias. They never stop to consider that even one transitional fossil contradicts the concept of special creation.
But the questions should flow in the other direction. Creationist should be asked: “Why does every fossil ever found support the theory of evolution by having a specific place in the tree of life? Where are the anachronistic fossils? Where are the preposterous fossils and the incongruous fossils that we should expect if the tree of life is incorrect?”
When we ask for anachronistic fossils, what specifically are we asking for? We want to see evidence supporting the Noah’s Ark model — evidence indicating that all species (or “kinds”) existed at the same time, rather than gradually evolving over billions of years. Bring us the fossil of a present day mammal — a bunny rabbit — that was undeniably found in a fossil bed together with long-extinct creatures that evolution says were living 500 million years ago. (Mammals are believed to have first appeared approximately 220 million years ago.)
Don’t get cute now. We won’t be impressed if you show us something that evolved long ago and which still exists. Not every old form has gone extinct, and we all know, for example, that sponges — an ancient class of animals — still have several species that are alive today. A persistent species isn’t going to do the trick, so don’t bring us evidence of contemporaneously-existing rabbits and sponges. We want to see something (like the rabbit) that evolution theory says developed very late but which you can convincingly demonstrate was actually living well before its evolutionary ancestors. Show us a trilobite from the Cambrian or Paleozoic era and a bunny rabbit in the same undisturbed fossil layer. That would shake the theory of evolution to its foundations. Go ahead and dig. Fame awaits you. What are you afraid of?
What else are we asking for? Show us a creature that is impossible, considering what should have been its evolutionary ancestry. For example, the precursors of mammals and birds had already diverged from their common reptilian ancestor before the evolution of what we would recognize as mammals and birds. Because mammals and birds emerged from such well-separated lines of descent, there should be no mammals with feathered wings, at least not according to the theory of evolution. We want to see something that had to be specially created — perhaps a Pegasus — a species that can’t fit into the tree of life. In other words, if evolution theory is wrong and species exist that couldn’t possibly have evolved, then show us the evidence!
If creationists (including Intelligent Design creationists) want to challenge the tree of life, the burden is on them produce something — some verifiable evidence that is inconsistent, incompatible, and irreconcilable with the theory of evolution. But the likelihood that a creation “scientist” will do productive research is slim indeed. Why should they do research? They already know all the answers (or so they imagine).
See also: Creationism and the Burden of Proof.
Copyright © 2008. The Sensuous Curmudgeon. All rights reserved.