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
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
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.
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?
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
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.
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.
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,