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Re: Semantics? (Homo species)
Philip Deitiker (pdeitik@bcm.tmc.edu)
Thu, 19 Dec 1996 21:36:42 GMT
prockstroh@aol.com (Prockstroh) wrote:
>Hello,
>I'm an anthropology major with a question that has been bugging me for a
>while. I've asked several professors, but they always get kind of crabby
>about it.
>I've been wondering why it is that, whenever someone finds a new jawbone
>or skeleton or whatever that resembles us in some way, they call it Homo
>boisei or Homo habilis or Homo XXX, rather than just plain old Homo
>sapiens. Usually, the difference is based on a slight skeletal difference
>(jawbone? skull size? Physical anthro. is not my strong point).
>If you look at, say, a Chihuahua skeleton compared to that of a
>Rottweiler, you see all kinds of differences, but they're still the same
>subspecies. So why are humans put in all these different groups?
>One professor gave me the cold freeze when I asked her about it. Another
>said it was just a semantic difference that only applied to humans. Yet
>another went off on a tangent and never really got around to addressing
>the question. I figure that it never hurts to ask the same question over
>and get new ideas.
I am not an anthropologist, but I don't think one can strictly
attribute this to human idiosyncracies. Your question is really 2
question. The first question is under what circumstansis should
something be consider a Homo and something be considered and
australopithicus, pan, or gorilla. The answer is probably best
described in terms of the kind of serendipitous way science does
things. In biochemistry, one discovers a new factor and gives it a
temporary tag (a kind of label for identification until the real
structure function arguments can be worked out). Unfortunately, if the
the structure/function studies become popularized long before the
desired results are acheived, the temporary name may stick (just like
a popular nick-name might stick instead of a persons real name) and
then its kind of difficult to change the status quo. This nomenclature
problem is not unique to pan/homo.
The second problem is when to define a species. Lots of heated
debate in the evolution section concerning human, but I think the
nomencaluture used may be justified. For example neaderthals have been
defined by many as a species, and the synthesis of the fossile studies
and genetics studies indicate that Neaderthal was a species. More
complicated is the transition between erectus and sapiens. Recent
evidence indicates that erectus coexisted for a short time in asia
with sapiens and should be treated as a separate species.
Where this gets complicated is that sapiens evolved from erectus
(presumbably erectus africanus) thus if one uses a biforkation model
for speciation erectus asiatus should be something like Homo
neoasiatus since erectus implies interbreeding potential with
anscestral lineages. Either way its a moot point since both pre sapien
erectus and asian erectus are gone so breed potential cannot be
demostrated. But the asiatic erectus skulls look close enough that
maybe a new species title should not be defined.
Anyway, during the last 2 years there has been strong evidence
put forth that 3 Homo species simultaneously exist in eurasia from 90
- 35 KYA. Erectus or asaitic species formed 1.8M to 70KYA (depending
on classification), sapiens formed 600 to 200KYA, and neadertahlensis
1.2M to 600KYA. One could argue that if one finds a bone with
morphological or dating differences compared to previous finds that
maybe that find should be called a species and assume that there were
always species forming and disentigrateing at the rate of 1/400K to 1M
years, based upon the model above. Your going to find that the 3
species theory is of great debate, particularly amoung people who
proport multiregional origin; however, there is a growing body of
support for out-of-africa origin model which simulatneously supports a
faster rate of hominid species formation. If upheld, then then species
nomenclature may be justifyable or even considered conservative.
Philip
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