Sunday, October 9, 2011 - 0 comments

Once We are NOT Alone : 1. A Preview

By : Ian Tattersall

Homo sapiens has had the earth to itself for the past 25,000 years or so, free and clear of competition from other members of the hominid family. This period has evidently been long enough for us to
have developed a profound feeling that being alone in the world is an entirely natural and appropriate state of affairs.

So natural and appropriate, indeed, that during the 1950s and 1960s a school of thought emerged that claimed, in essence, that only one species of hominid could have existed at a time because there was simply no ecological space on the planet for more than one culturebearing species. The “single-species hypothesis”
was never very convincing even in terms of the rather sparse hominid fossil record of 40 years ago. But the
implicit scenario of the slow, singleminded transformation of the bent and benighted ancestral hominid into the
graceful and gifted modern H. sapiens proved powerfully seductive—as fables of frogs becoming princes always are.

So seductive that it was only in the late 1970s, following the discovery of incontrovertible fossil evidence that hominid species coexisted some 1.8 million that the single-species hypothesis was abandoned. Yet even then, paleoanthropologists continued to cleave to a rather minimalist interpretation of the fossil record. Their  tendency was to downplay the number of species and to group together distinctively different fossils under
single, uninformative epithets such as “archaic Homo sapiens.” As a result, they tended to lose sight of the fact that many kinds of hominids had regularly contrived to coexist.

Although the minimalist tendency persists, recent discoveries and fossil reappraisals make clear that the biological history of hominids resembles that  of most other successful animal families. It is marked by diversity rather than by linear progression. Despite this rich history— during which hominid species developed
and lived together and competed and rose and fell—H. sapiens ultimately emerged as the sole hominid. The
reasons for this are generally unknowable, but different interactions between the last coexisting hominids—H. sapiens and H. neanderthalensis—in two distinct geographical regions offer some intriguing insights.

Next : A Suites of Species


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