MUNsolved Mysteries


(Feb. 6, 1997, Gazette)

Have a burning question pertaining to science, engineering, medicine, the arts, music, humanities, social sciences, physical education, or any other field? Let us know; we'll do our best to find the answers for you, drawing upon the expertise of members of the university community.

Tony Goudie of the Centre for Institutional Analysis and Planning has been wondering about evolution lately.

"Scientists say that humans continue to evolve physically. For example, I've read that, over time, we may lose our little fingers and toes. Is there evidence of this? What physical changes can we expect in the next thousand years (or 10,000 years)? When can we expect certain changes? How much time is required for an adaptation to occur?"

Dr. Stuart Brown, Department of Anthropology, was kind enough to share some of his knowledge of the subject with us.

"There are several interrelated long-term trends in hominid evolution over the last four million years, such as decreasing sexual dimorphism (the difference in size between females and males); decreasing skeletal robusticity and tooth size; recession of the dental arcade behind the vertical plane of the face; increasing brain size, and so forth. But it's probable that we have reached, or are close to, the limits of these trends," he explained.

Dr. Brown said we are relatively young as a species, and have adapted mainly through changes in behavior -- not bone or cell structure -- during our collective lifetime.

"We Homo sapiens sapiens (as opposed to earlier ancestral or parallel hominid lineages) are only perhaps 150,000 years old, during which time we have changed little biologically though much behaviorally. Further increase in brain size, for example, would require either shorter gestation in the womb (which future mothers might welcome!) or a wider pelvic structure (but this would interfere with locomotion!) Our intelligence and complex cultural behavior have fundamentally altered though not eliminated the effects of natural selection," Dr. Brown observed. "For example, the emergence of a new species usually occurs in small isolated populations, but modern mass migrations and means of communication reduce that possibility for us to insignificance. But who knows where genome research will take us (all aboard for the island of Dr. Moreau?!) And some have argued that computers will soon be so miniaturized and complex as to constitute a genuine extension of, and improvement on, human intelligence (Homo sapiens sapiens giving rise to Homo technologicus siliconus?)."

Are we still evolving? How could we not, asks the anthropologist.

"The problem is that evolution is a random process with no predetermined direction, and science provides no crystal balls. If we take the palaeontological record as a predictor of our future, the average for the longevity of vertebrate species is around two million years and, indeed, the once-prolific hominid bush is now reduced to a single twig -- ourselves," said Dr. Brown. "The question we should ask ourselves is whether we can avoid military conflagration or environmental strangulation long enough to see what the next million-odd years will bring us. On the other hand, that same palaeontological record points to our inevitable extinction. In the short term, will we lose our small fingers and toes in the next 10,000 thousand years? Not likely! Will we all become large-headed chinless wonders? I doubt it -- dear old Joe Clark never was the wave of the future."

Hey! Let's stop measuring the size of our heads. Why not send a question to MUNsolved Mysteries, Gazette, Arts and Administration Building, Memorial University of Newfoundland, St. John's, Nfld., A1C 5S7; e-mail gazette@morgan.ucs.mun.ca, or fax 709-737-8699. Please include your name and telephone number.