Transitional forms

From PhiloWiki

Some have claimed that there are gaps in the fossil record, indicating a lack of transitional forms. How are these perceived gaps in the fossil record explained? What about transitional forms such as archaeopteryx? Why are there no transitional forms to show the evolution of dogs?

Transitional forms are evidence for evolution

Nineteenth-century English social scientist Herbert Spencer made this prescient observation: "Those who cavalierly reject the Theory of Evolution, as not adequately supported by facts, seem quite to forget that their own theory is supported by no facts at all." Well over a century later nothing has changed. When I debate creationists, they present not one fact in favor of creation and instead demand "just one transitional fossil" that proves evolution. When I do offer evidence (for example, Ambulocetus natans, a transitional fossil between ancient land mammals and modern whales), they respond that there are now two gaps in the fossil record.

This is a clever debate retort, but it reveals a profound error that I call the Fossil Fallacy: the belief that a "single fossil"--one bit of data--constitutes proof of a multifarious process or historical sequence. In fact, proof is derived through a convergence of evidence from numerous lines of inquiry--multiple, independent inductions, all of which point to an unmistakable conclusion.

We know evolution happened not because of transitional fossils such as A. natans but because of the convergence of evidence from such diverse fields as geology, paleontology, biogeography, comparative anatomy and physiology, molecular biology, genetics, and many more. No single discovery from any of these fields denotes proof of evolution, but together they reveal that life evolved in a certain sequence by a particular process...

One of the finest compilations of evolutionary data and theory since Charles Darwin's On the Origin of Species is Richard Dawkins's magnum opus, The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution (Houghton Mifflin, 2004)--688 pages of convergent science recounted with literary elegance. Dawkins traces numerous transitional fossils (what he calls "concestors," the last common ancestor shared by a set of species) from Homo sapiens back four billion years to the origin of heredity and the emergence of evolution. No single concestor proves that evolution happened, but together they reveal a majestic story of process over time."

Consider the tale of the dog. With so many breeds of dogs popular for so many thousands of years, one would think there would be an abundance of transitional fossils providing paleontologists with copious data from which to reconstruct their evolutionary ancestry. In fact, according to Jennifer A. Leonard, an evolutionary biologist then at the Smithsonian Institution's National Museum of Natural History, "the fossil record from wolves to dogs is pretty sparse." Then how do we know whence dogs evolved? In the November 22, 2002, Science, Leonard and her colleagues report that mitochondrial DNA (mtDNA) data from early dog remains "strongly support the hypothesis that ancient American and Eurasian domestic dogs share a common origin from Old World gray wolves."

In the same issue, molecular biologist Peter Savolainen of the Royal Institute of Technology in Stockholm and his colleagues note that even though the fossil record is problematic, their study of mtDNA sequence variation among 654 domestic dogs from around the world "points to an origin of the domestic dog in East Asia" about 15,000 years before the present from a single gene pool of wolves.

Finally, anthropologist Brian Hare of Harvard University and his colleagues describe in this same issue the results of a study showing that domestic dogs are more skillful than wolves at using human signals to indicate the location of hidden food. Yet "dogs and wolves do not perform differently in a nonsocial memory task, ruling out the possibility that dogs outperform wolves in all human-guided tasks," they write. Therefore, "dogs' social-communicative skills with humans were acquired during the process of domestication."

No single fossil proves that dogs came from wolves, but archaeological, morphological, genetic and behavioral "fossils" converge to reveal the concestor of all dogs to be the East Asian wolf. The tale of human evolution is divulged in a similar manner (although here we do have an abundance of fossils), as it is for all concestors in the history of life. We know evolution happened because innumerable bits of data from myriad fields of science conjoin to paint a rich portrait of life's pilgrimage.

The Fossil Fallacy from Scientific American  Michael Shermer

Transitional forms do not exist, and evolution is false

Gaps in the fossil record disprove evolution [pp 44].

Case for a Creator from   Lee Strobel

Evolutionists claim that dinosaurs evolved over millions of years. They imagine that one kind of animal slowly changed over long periods of time to become a different kind of animal. For instance, they believe that amphibians changed into reptiles (including dinosaurs) by this gradual process. This would mean, of course, that there would have been millions of creatures during that time that would be 'in between,' as amphibians evolved into reptiles. Evidence of these 'transitional forms,' as they are called, should be abundant. However, many fossil experts admit that not one unquestionable transitional form between any group of creatures and another has been found anywhere. If dinosaurs evolved from amphibians, there should be, for example, fossil evidence of animals that are part dinosaur and part something else. However, there is no proof of this anywhere. In fact, if you go into any museum you will see fossils of dinosaurs that are 100% dinosaur, not something in between. There are no 25%, 50%, 75%, or even 99% dinosaurs—they are all 100% dinosaur!

How Do Dinosaurs Fit with the Bible? from Answers in Genesis  Ken Ham