It’s one of those questions that many never ask because they are so used to hearing the Correct Answer that no other answers surface. And they would not, of course, know objections to the Correct Answer. Anyway, Jonathan Witt raises the common design possibility:
To say that similarities prove common descent ignores a logical possibility: that common features may instead be due to a common design strategy. Think of cars. A Tesla and a Cadillac share many features — four wheels, synthetic rubber tires, brakes, two axles, windshield wipers, headlights. But of course, none of that means that Teslas blindly evolved from Cadillacs, or vice versa. Designers re-use design features proven to work for specific engineering needs, even while they innovate in alternative directions, as Tesla CEO and engineer Elon Musk has with his electric cars.
We see this pattern even across disparate technology platforms. In one case, the wheel is used and adapted for a water mill. In another case, for a gear in a watch. In another case, for a bicycle. In still another case, for a pizza cutter. In yet another, for a truck. And in another, for a self-balancing scooter (aka “hoverboard”).
So, what about with living things? Might a designer of life have used and reused various good design concepts in widely different biological contexts? The only way to jump straight from biological similarities to common descent via blind evolution is to rule out the design hypothesis from the start — to treat it as the idea that must not be considered, the thought that must not be thought. But if we are seeking the truth about the history of life on Earth, we shouldn’t let ourselves be bullied into ignoring one option and accepting the other as unquestionable dogma.Jonathan Witt, “Forbidden Question: Common Descent or Common Design?” at Evolution News and Science Today
It’s a dogma that provides aid and comfort for many. There are, of course, many reasons for doubt, including the remarkable number of instances of convergent evolution.
Witt offers another example (among many):
If we step back from chromosome 2 in humans and look at genetic evidence more broadly, we find a bigger problem with the idea of the macroevolution of all life from a common ancestor. Finnish bioengineer Matti Leisola and I highlight that problem in our book Heretic: One Scientist’s Journey from Darwin to Design:
“In 1965 one of the most important scientists of the last century, Linus Pauling, and biologist Emil Zuckerkandl, considered by some as the father of molecular biology, suggested a way that macroevolution could be tested and proved: If the comparison of anatomical and DNA sequences led to the same family tree of organisms, this would be strong evidence for macroevolution.7 According to them, only evolution would explain the convergence of these two independent chains of evidence. By implication, the opposite finding would count against macroevolution.“
So what were the results? Over the past twenty-eight years, experimental evidence has revealed that family trees based on anatomical features contradict family trees based on molecular similarities, and at many points. They do not converge. Just as troubling for the idea of macroevolution, family trees based on different molecules yield conflicting and contradictory family trees. As a 2012 paper published in Biological Reviews of the Cambridge Philosophical Society reported, “Incongruence between phylogenies derived from morphological versus molecular analyses, and between trees based on different subsets of molecular sequences has become pervasive as datasets have expanded rapidly in both characters and species” (emphasis in original).8
Another paper, published the following year in the journal Nature, highlighted the extent of the problem.9The authors compared 1,070 genes in twenty different yeasts and got 1,070 different trees.10
These results are unexpected, even bizarre, on the assumption that all life evolved from a single common ancestor through a long series of small, random genetic mutations over millions of years.Jonathan Witt, “Forbidden Question: Common Descent or Common Design?” at Evolution News and Science Today
If you didn’t hear about that, ask yourself why that might be.