Sunday, August 7, 2011

Just us humans

I often save articles I read on the internet that interest me and occasionally I like to go through my database of articles and just see what all is there.  I've been saving articles for a while and have a quite a lot of them, so it's hard to remember what all is there sometimes.

Today I came across an article I had forgotten about and decided to reread it.  It was from December 2004 and it was titled "Believe it or not, they're all the same species." The article suggests there are not multiple human species that have existed over time on earth, but just one single species that has had some variations along the way.

Here is an excerpt from the article:

The number of human species claimed by fossil-hunters now stands at around 10, while the total number of human-like species exceeds 50. Such claims have long been based on supposedly significant differences in sizes and shapes of fossil bones. Now they have all been thrown into doubt by research showing that the differences lie within the range expected for just a single species.

Professor Maciej Henneberg, of the University of Adelaide, a world authority on fossil human anatomy, made the discovery after analysing the skull sizes and estimated body weights for all of the 200 identified specimens of human-like fossils known as hominims. These span the entire history of humans, from the emergence of so-called Australopithecines with an upright stance more than four million years ago to neolithic modern humans from around 10,000 years ago.

Prof Henneberg found that the fossils show clear evidence of evolution, with substantial increases in both skull sizes and body-weight. However, he also found that the fossils show no evidence of being anything other than a single species which had grown bigger and smarter over time. According to Prof Henneberg, the much-vaunted differences in fossil size used to identify "new" species all lie within the normal range expected for one species.

I don't believe in evolution -- at least not Darwin's theory of evolution.  Sure, there may be some 'evolution' in the sense that there are variations or mutations within the same species, but the idea that one species turns into another species over time is garbage, in my opinion.  Any variations that occur are probably just variations to code that already exist within the genome anyways.  Considering there are species that have existed since the time of dinosaurs unchanged, I see no reason to believe that species eventually evolve into brand new species over time.  So the idea that there is only one human species throughout history makes sense to me.

But this also had me wondering how they come up with all these supposedly different species of humans in the first place and reminded me of a find from last year that was lauded as yet another species of human.  The 'evidence' came from a single pinky finger bone.  I could hardly see what the excitement was.  Could they really declare a new species just from a pinky finger bone?  The declaration was based on DNA evidence alone.  But is that really enough?  DNA has been called the "gold standard or proof in criminal cases,"but is that really true either?  A New York Times article from 2009 says that DNA evidence can be fabricated.  Here is an excerpt from that:
Scientists in Israel have demonstrated that it is possible to fabricate DNA evidence, undermining the credibility of what has been considered the gold standard of proof in criminal cases.

The scientists fabricated blood and saliva samples containing DNA from a person other than the donor of the blood and saliva. They also showed that if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile without obtaining any tissue from that person.

I doubt that our prehistoric ancestors conspired to fabricate the DNA of a single pinky bone in the hope that many thousands of years later someone would find it and confuse it for another species of human. But contamination may still be a possibility or it may just be possible that the difference really isn't significant enough to declare a new species.  I mean, how important is DNA in determining the similarities and differences between species anyways?  Apes are our closest relatives in the animal kingdom and have DNA that is 95-98% similar to ours, and they are the most similar to us as far their body structure goes.  But the DNA of zebrafish is 92% similar to ours, which still sounds like a pretty close match.  But you don't see much physical resemblance between us and zebrafish.

Granted, I don't know much about DNA and have no formal education on the subject.  I don't doubt the authenticity of the science or it's benefits, but maybe it shouldn't be considered the gold standard of proof in criminal cases or in determining whether or not a fossil is a separate species of human either.

Even today, you can see differences in modern humans.  We're not all the same size or color.  We don't all have the same kind of hair.  We don't all live the same kind of lifestyle either.  But we are all still human.  And it would seem that it may have always been that way since the birth of humanity.

1 comment:

  1. I'm with you on the evolution thing, so far as I haven't found it to make a lot of sense, but then there are different races and ironically those near the equator have more melanin, so it's possible that we do adapt to our locations in some ways, but as a species...don't know about that. I think it's possible that, like animals, there can be many kinds of canines, but some become extinct, some breeds simply have bad location and illnesses that finish them off and it's not necessarily a matter of evolving, simply the dying off of less viable variants.