Happy Birthday Darwin; Hello Homo Evolutis

As we mark Charles Darwin's 200th birthday, a biotech entrepreneur has offered an eye-opening suggestion: that science is bringing us ever-closer to a time when natural selection may yield to human self-design.

In terms of conversation and controversy, we may not have seen anything yet.

The man making this proposal is Juan Enriquez, chairman and CEO of the research and investment firm Biotechonomy. He explained his provocative idea last week at the 2009 Technology, Entertainment, Design Conference in Long Beach, Calif.

To understand it, we begin with a definition. Speciation is the evolutionary process by which new biological species arise. As Darwin effectively demonstrated, this can happen as the genetic makeup of a single species evolves into two or more similar but structurally unique species. Over time, a new species develops attributes so differentiated from those of its ancestors that its genetic code no longer matches its parent. Speciation of this sort is complete when two critters, descended from a single parent, can no longer create offspring with each other. Stated differently, these two can no longer contribute and mix their genes to form a new sprout.

The origin of some speciation is clear in geographic instances, where species that have moved, or reside in regions that have undergone change, genetically adapt to the new terrain. In this case, species add characteristics that help with survival in their remodeled homes and lose those that are no longer useful.

A colorful, if annoying, example is the London Underground Mosquito, first discussed in the scientific literature in 1998. While these insects descended from surface mosquitoes, flying about overhead and sustaining themselves by biting birds, this particular pest has evolved to feed only on underground mammals, including mice, rats and, according to The Times of London, maintenance workers. Scientists have determined that these mosquitoes can no longer reproduce with their above-ground, bird-biting relatives, and thus are a truly new species.

Evolution of this sort, understandable when observing the creature's surroundings, is known as natural selection. However, other genetic changes occur for less observable reasons. These more random generational changes are described as genetic drift.

Multiple Species of Humans?

Now here is where it gets much more interesting. In his talk at TED, Enriquez said the fact that we are the only living species of humans is an anomaly -- or at least out of synch with history. Millions of years ago, there were as many as five different species of humans co-existing on the planet.

Well, hooray! Perhaps modern humans are the end-result of all evolution. Perhaps we have reached the very pinnacle of natural selection and genetic drift. On the other hand, Enriquez suggested, perhaps those are slightly arrogant conclusions.

Until now, scientists have demonstrated that genetic changes in a single species have occurred slowly, over relatively long periods of time. However, in his talk, Enriquez showed photos of human-engineered genetic experiments which have successfully "reprogrammed" one cell into becoming another, completely different cell, added extra wings to chickens, and perhaps most importantly, engineered medical replacements for defective knees, weak tendons and failing critical human organs. Enriquez suggested that these one-off experimental procedures are only the first rung on a most interesting ladder.

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