Close your eyes and imagine
Africa as it would have been 1.6
million years ago. The sun radiating in the sky, the fish swimming in the marshes, the-
wait, whoa, huh? marshes?
That's right. Marshes. An examination of
sediments at
Nariokotome in
Kenya show that the area was a
floodplain. For quite a while. It wasn't always the dry, dusty image with
coke bottles falling from the sky we see in the movies. Rather, it was humid. It supported lush green life which sheltered lizards and young fish among reeds in shallow water. When the
Omo River overflowed,
Nariokotome sprang with life.
It was then, in that lush setting teeming with
aquatic life that a young boy lived and died. He was much like the
Masai people that inhabit Kenya today, with long, slender limbs that helped him survive in the African heat. He had a bone structure that allowed him to walk and run with a grace that would make
Olympic Gold Medallists weep. He also had an infection from
gum disease that led to his death at the young age of 9 or 10.
His body came to rest in a place near
Lake Turkana amongst greenery, so it's fitting that 1.6 million years later it would be the growth of
life that reintroduced him to the world. A
mesquite tree took to seed and began to grow from the
fossilized cranium of the boy, slowly bringing
fragments of bone to the surface. In 1984 those fragments were found.
-The discovery-
In the 70s Africa was at the center of the world's stage as the
Leakey family made one discovery after another at
Olduvai Gorge. Then things trickled to a stop. By the 80s it was believed Africa had been picked dry, that nothing of significance would be found there. But
Richard Leakey along with wife
Meave and their friend
Alan Walker believed otherwise. In 1984 they assembled a team of experienced
fossil hunters and sought out the fragments that only their trained eyes would see. The leader of the hunters, Kamoya Kimue, was the first to make a discovery.
Kimue found small pieces of a
hominid skull. This was all that was needed to put the rest on the scent, carefully scouring the area in search of the remaining fragments and bones. What they ended up with - after four years of
excavation - was the nearly complete
skeleton of what appeared to be a 12 year-old boy.
wait. didn't you say he was 9 or 10?
The most complete
Homo erectus skeleton ever found, Turkana Boy (as he was dubbed) was only missing the hands and feet along with one
humerus. A quick look at his
mandible showed he'd just received his second
molars. This is consistent with a human around the age of 12. However, when they looked at the growth lines on his teeth they saw that Turkana Boy was actually only 9 or 10. This meant that he matured quickly.
-What else do the bones say?-
Turkana Boy's skeleton tells an interesting story. His small molars indicate he was
omnivorous, no longer needing the large teeth to grind plants and nuts. Coupled with his long limbs and a height that would have put him at 6' as an adult, we can surmise that he probably
scavanged meat after traveling long distances. The neck of his
femur is longer than in modern man, providing a better range of
mobility. He also had extra
vertebrae and thicker femur bones which provided more support for his
frame than we experience today.
why is that?
The
pelvis of Turkana Boy is quite narrow, which suggests that infants were born with small brains that grew rapidly after
birth. In order for our
species to
evolve from the 900cc brain that Turkana Boy had to the 1350cc brain we now have, the pelvis had to widen. We lost the extra vertebrae and thicker femurs with their long necks to make room for babies with a larger capacity to
learn and the ability to
speak (something it's thought Turkana Boy may not have been able to do since the opening his
spinal chord would have occupied in the vertebrae is small). In short, for bigger brains we have to endure some limits in our
bipedalism as well as lower back pain.
-The ramifications-
Turkana Boy's discovery came at the height of the
creation vs evolution battle. Before he was found many people sat on the fence concerning the matter for a lack of
evidence. When the first nearly complete skeleton of what is clearly a
human was discovered, and then was dated to 1.6 million years in age, many people fell off the fence.
At the same time some scientists were unsure of whether it should be
classified as
Homo erectus or not. It had all the right developments and characteristics to be classified as such, but it had some differences as well. The unusual extra vertebrae, the thick femurs with their long necks, made some think perhaps it should be considered a new species. Despite his firm belief that Turkana Boy is, in fact,
Homo erectus, Rickard Leakey eventually went with the classification
Homo ergaster. To this day Turkana Boy is referred to as
Homo erectus/Homo ergaster as the line between the two is pretty thin.
References:
Talk Origins, www.talkorigins.org/faqs/homs/15000.html
Searching for Our Origins, www25.brinkster.com/jmcginn/homo_erectus/ knm_wt_15000/knm_wt_15000.asp
The Lake Turkana Boy, www.mc.maricopa.edu/dept/d10/asb/learning/ origins/hominid_journey/turkana.html
What Bones Tell Us About Human Evolution,
www.saitama-kenpaku.com/jinrui/special/ english/number/07_E/factor05_02.htm
Africa, www.homepages.hetnet.nl/~krocat/english/afr_cont.htm