Page 24 of “The
Origin of Life” cites Henry Gee:
A second,
more serious challenge is the lack of proof that those creatures are somehow
related. Specimens placed in the series are often separated by what researchers
estimate to be millions of years. Regarding the time spans that separate many of
these fossils, zoologist Henry Gee says: “The intervals of time that separate the
fossils are so huge that we cannot say anything definite about their possible
connection through ancestry and descent.” (Brochure’s footnote: Henry Gee does not suggest that the theory of evolution is wrong.
His comments are made to show the limits of what can be learned from the fossil
record.) – In Search of Deep
Time—Beyond the Fossil Record to a New History of Life, by Henry Gee, 1999, p. 23.
======
The
following is the immediate context of the passage.
======
It has been
a productive week. Nzube, Gabriel, Robert, and others on the team have
unearthed hominid remains—no complete skulls or skeletons, because these are
rare indeed, but evidence enough that could, after study, reveal something
about the hominids that had lived in this region 3.3 million years ago.
In all, it
has taken approximately 250 man-hours of work to produce enough hominid
fragments to half-fill a tin box that Meave carries around on the passenger
seat of her truck. Almost all the specimens were pieces of tooth. It does not
sound like much, given all that effort, but it is more than most fossil hunters
expect, even from a site that had already yielded a few hominid bones and had
earlier been marked as promising.
Before I
told everyone else about my own find, straddled on that ridge overlooking an
expanse of space and, figuratively, an expanse of time, I wondered fleetingly
if it might have been part of a hominid—perhaps half a tooth, like the one
Gabriel found. In my mind I was already holding the fragment between finger and
thumb, turning it over in the light. The question immediately presented itself:
could this fossil have belonged to a creature that was my direct ancestor?
It is
possible, of course, that the fossil really did belong to my lineal ancestor.
Everybody has an ancestry, after all. Given what the Leakeys and others have
found in East Africa, there is good reason to suspect that hominids lived in
the Rift before they lived anywhere else in the world, so all modern humans
must derive their ancestry, ultimately, from this spot, or somewhere near it.
It is
therefore reasonable to suppose that we should all be able to trace our
ancestries, in a general way, to creatures that lived in the Rift between
roughly 5 and 3 million years ago. So much is true, but it is impossible to
know, for certain, that the fossil I hold in my hand is my lineal ancestor.
Even if it really was my ancestor, I could never know this unless every
generation between the fossil and me had preserved some record of its existence
and its pedigree. The fossil itself is not accompanied by a helpful label.
The truth is that my own particular ancestry—or
yours—may never be recovered from the fossil record. The obstacle to this
certain knowledge about lineal ancestry lies in the extreme sparseness of the
fossil record. As noted above, if my mystery skull belonged to an extinct giant
civet, Pseudocivetta ingens, it would be the oldest known record of this species by a million years. This
means that no fossils have been found that record the existence of this species
for that entire time; and yet the giant civets must have been there all along.
Depending on how old giant civets had to be before they could breed (something
else we can never establish, because giant civets no longer exist so that we
can watch their behaviour), perhaps a hundred thousand generations lived and
died between the fossil found by me at site LO5 and the next oldest specimen.
In addition, we cannot know if the fossil found at LO5 was the lineal ancestor of the specimens found at Olduvai Gorge or Koobi
Fora. It might have been, but we can
never know this for certain. The intervals of time that separate the fossils
are so huge that we cannot say anything definite about their possible
connection through ancestry and descent. (Gee,
pages 22-23; underlining added)
