Tree of Life on the Way Out

by Stephen Caesar

One of the best-known evolutionary images is the “tree of life,” which shows the human family tree growing from primitive, ape-like ancestors to full-fledged humans. At the base of its “trunk” is a small primate whose evolutionary descendants form large, separate “branches.” Each major branch then breaks into smaller branches, and so on, up to modern man. It has been one of the most effective tools in tricking people into believing in human evolution, and it is being scrapped.

The journal Science News featured an article on the slow death of this icon, subtitled “The science of body development may make kindling out of evolutionary trees.” It began by stating: “Over the past 25 years, paleoanthropologists have nurtured one evolutionary tree after another, hoping to reap ever sturdier portrayals of humanity’s descent” (Bower 2000:346). It then reported: “Recently, investigators have become fond of assigning new fossil finds to unique rather than established species, so evolutionary trees have gotten downright bushy” (ibid.).

This development stems from a discipline known as “cladistics,” in which scientists create an evolutionary tree of life based on bone and tooth measurements from hundreds of fossils, which are then fed  into a computer program. The article went on to state that “a growing number of investigators, including some formerly ardent evolutionary-tree nurturers now suspect that the branching cladistic creations suffer from conceptual root rot. The whole enterprise rests on shaky biological and misleading statistical assumptions, they say” (ibid.).

One example is Tim White of UCLA Berkeley, co-discoverer of “Lucy.” Originally, he “spawned his share of evolutionary trees. Over the past decade, though, advances in developmental biology have led him to abstain from that practice” (ibid.). His change of mind came from the discovery that, although the shape and arrangement of any organism’s bones are determined by genes as it develops from fetus to adult, the bones can respond flexibly to influences in their natural surroundings. As a result, assessments of what constitutes a species, based on bones alone, are inaccurate. Dr. White concluded: “You can’t [break up] skeletal anatomy, put all of the traits into a [statistical computer] program, and generate something that makes biological sense. A lot of people who have published cladistic trees are going to be in trouble” (ibid.).

Bernard Wood of George Washington University and Mark Collard of University College, London, agree. They note that skull and tooth measurements from humans, chimps, gorillas, and orangutans have given rise to several trees of life that have been contradicted by genetic trees of life. Moreover, the bone and tooth measurements used to create these unreliable modern trees are often the same measurements used to create trees of life for alleged evolutionary ancestors, because evolutionists assume that what applies in the present applied equally in the past. Science News commented:

“Ongoing research in developmental biology raises ominous warning signs about such assumptions. It indicates that many features of bones and teeth arise as by-products of other traits during an individual’s skeletal development. Wood, who until recently was an avid and influential evolutionary tree builder, now doubts the accuracy of cladistics as currently practiced” (ibid. 347).

Like-minded anthropologists include C. Owen Lovejoy of Kent State, who stated: “Anthropologists arbitrarily choose anatomical traits for cladistic analysis. We need to find out how these traits develop and which ones truly have an evolutionary signal” (ibid.). Another is Timothy Bromage of City University of New York, who said: “We can’t solve debates over Neanderthals or any other human ancestors using anatomical characteristics that are subjectively defined and don’t have a clear relationship to evolutionary history” (ibid.).

Yet another icon of evolution crumbles.

Reference:

Bower, B. 2000. “Out on a Limb.” Science News 158, no. 22.

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Stephen Caesar holds his master’s degree in anthropology/archaeology from Harvard. He is the author of the e-book The Bible Encounters Modern Science, available at www.1stbooks.com.