Human ancestry in Olduvai Gorge... ?

Question

Olduvai Gorge contains the fossils of Australopithecus bosei, Homo habilis and Homo erectus. However, between Australopithecus bosei and Homo habilis, there should be fossils of Homo rudolfensis, as this is how human evolution supposedly went.

So why are there no Homo rudolfensis fossils even though there are ones of the other three?

Answer 1

They might be there, but just haven't been found yet.  Remember, absence of proof is not proof of absence.

Answer 2

Conditions for fossilization are pretty specific, if the population was low at that time then the fossils may just be extremely rare.  Maybe there wasn't even a population in that particular area at that time.

I really don't know why, but I do know that fossils are hard to come by under even the best conditions.  And, more importantly, I know that one piece of missing data is NOT reason to abandon an idea when you have piles of other data supporting the idea.  Knowledge will always be incomplete, and just because something is unknown today doesn't mean it will always be unknown.

Answer 3

It might be that H. rudolfensis never lived at Olduvai.

H. rudolfensis may have originated and lived elsewhere.  It was only later that H. habilis journeyed from elsewhere and settled in Olduvai.

For an analogy, there are no ancient pre-human hominid fossils in North America, but plenty of human bones from the past 12,000 or so years.  That's because hominids didn't originate in North America.  They migrated there (in several waves) from elsewhere.

Answer 4

Your assertion that H. rudolfensis should be found at Olduvai Gorge does not hold.

The reason that Olduvai Gorge is a good place for finding fossils is that the river cut through prehistoric plains region, exposing the fossils.  It may well be that the conditions during the H. rudolfensis timespan did not favor them living there, so they would not be exposed,  There is extensive evidence of hominid migration.

It is like saying that New York was controlled by Native Americans, then the Dutch, then England, but there is no evidence of Dutch control of Boston.