Daily Archives: November 13, 2010

Speciation by culture

If the argument for Man’s special place in Nature is moved to the ground of culture, Man’s position as an organism with unique qualities which differentiate him from all other organisms undoubtedly becomes stronger, but at the cost of threatening his position as a species as traditionally defined.

Objections have been raised to the conclusions of Everett and Gordon, primarily in terms of their interpretation of their observations, but assuming there is a fair degree of objective truth about their data, it is reasonable to ask are the Pirana teetering on the edge of what counts as fully human if behaviour is the defining criterion? It is the wrong question to ask. The right question to ask is can Homo sapiens be meaningfully designated a species as a species is defined for every other organism?

Because Man is differentiated profoundly by culture, the widely accepted definition of a species – a population of freely interbreeding organisms sharing a common gene pool – is unsatisfactory, for clearly Man is more than an animal responding to simple biological triggers. When behavioural differences are perceived as belonging to a particular group by that group as differentiating members of the group from other men, they perform the same role as organic differences for they divide Man into cultural species.

It is worth adding that the traditional concept of a species is far from secure. It is a man-made classification which is often found wanting. For example, the North American Ruddy Duck and the European White-Headed Duck are classified as separate species. The introduction of the Ruddy Duck to Europe has resulted in widespread interbreeding between the supposedly separate species to the extent that conservationists now fear for the survival of the White Headed Duck. It is also true that a growing amount of traditional taxonomic classification is being overturned by DNA analysis.

Another interesting trait is that members of a species will have different breeding propensities across its distribution, that is, members of the supposedly single species will breed differentially with different parts of the total species population. For example, take an animal which is common to Europe and bring individuals from different geographical parts of the continent together and it may be that those found in the East of the distribution will be less likely or refuse altogether to mate with the those in the West. These barriers to breeding are clearly not purely due to major differences in physical biology. Probably there is an element of behavioural difference which reduces the propensity to breed.

Animals use various triggers to breed: aural, chemical, condition of feathers and so on. These are seemingly automatic processes whereby one individual responds to another without conscious thought. Even behavioural triggers such as mating rituals can be viewed in the same light. Man, although not divorced entirely from such triggers, adds conscious thought to the process of mate selection. Does that not put Man in an entirely separate category to all other organisms, namely, the one organism who can potentially breed freely across the entire species population? Potentially yes, but in practice no for Man’s capacity for conscious thought and decision making does not mean his breeding is not constrained by the triggers which control other organisms, especially behavioural. For example, most people choose mates who are of the same race as themselves even when they have ample opportunity to do otherwise.

Even at the level of biology I wonder if Man is quite as discrete as he imagines. To the best of my knowledge no one has tried to create a cross between a human and a chimpanzee or a bonobo – I sincerely hope no one ever does. But putting aside any natural revulsion, would it be so surprising if such a cross was possible? Would it be any more of a intra-species leap than say the production of a mule or a liger (lion/tiger) through the mating of different species? I would not wish to bet against it. REsearch into intra species breeding has been moving on apace, viz:

 “The experiment: Cross-breed a human with a chimpanzee.

“The premise: The biologist Stephen Jay Gould called it “the  most potentially interesting and ethically unacceptable experiment I can imagine”. The idea? Mating a human with a chimp. His interest grew out of his  work with snails, where related species can display wide variation in shell architecture. Gould attributed this diversity to a few master genes which turn on and off the shared genes responsible for constructing the shells. Perhaps, he  speculated, the differences between humans and apes were also a factor of developmental timing: after all, adult humans have physical traits, such as  larger craniums and wide-set eyes, that resemble infant chimpanzees. This  phenomenon is known as neoteny – the retention of juvenile traits in adults of  later generations. Gould theorised that over the course of evolution, a tendency  toward neoteny might have given rise to human beings. By watching the development of a half-human, half-chimp, researchers could explore this theory  in detail.

“How it works: It would be frighteningly easy: the same  techniques used for in vitro fertilisation would likely yield a viable hybrid human-chimp embryo. Researchers have already spanned a comparable genetic gap  between a baboon and a rhesus monkey, and even though chimps have 24 pairs of chromosomes, and we have 23, this is not an insuperable barrier (although the  hybrid would likely have an odd number of chromosomes, and be unable to reproduce). As for the gestation and birth, it could be done the natural way.
Chimpanzees are born slightly smaller than humans, so it would make sense to grow the embryo in a human uterus.

“The payoff: Gould’s idea about neoteny remains controversial, to say the least. This experiment would help to resolve the debate – and, more broadly, illuminate how two species with such similar genomes could be so different. Its outcome would give biologists insights into the origin of our own species. Let’s hope they can find a less disturbing route to
get there. Jerry Adler “(http://www.telegraph.co.uk/science/science-news/8702999/Unethical-scientific-experiments-going-to-extremes.html)

As for the future, genetic engineering may break down distinctions between species, for example, by genes from one species being implanted into another. Lastly, genetics and/or cybernetics may lead to modifications of human beings so substantial to create what are to all intents and purposes unambiguously separate species of Man with vastly differing abilities. There may come a point where the concept of a species becomes redundant.

%d bloggers like this: