I suppose this article that appeared in today's Globe and Mail, Canada's national newspaper, could be seen as a response to the recent announcement of the opening of the Creation Museum in Petersburg, Kentucky, U.S.A., and about which I blogged here:
http://easynash.blogspot.com/2007/05/179the-debate-rages-on-new-creation.html
The upright truth about humans
We never walked on four feet - and neither do orangutans
ANNE MCILROY
SCIENCE REPORTER
June 1, 2007
We were never knuckle draggers.
Early humans didn't start out walking on all fours like gorillas and then slowly straighten up, a team of British researchers says. Instead, our ancestors became two-footed while nimbly traversing tree branches in search of fruit. When ancient rain forests began to thin out, they jumped down from the trees and starting walking on the ground.
"They stayed doing what they were doing in the first place," says Robin Crompton, with the department of human anatomy and cell biology at the University of Liverpool.
His work, published in today's edition of the journal Science, is based on the fossil record and observations of orangutans. It challenges the widely held notion that upright walking is uniquely human, something that distinguishes us from our closest relatives, the great apes.
Orangutans do it all the time, Dr. Crompton says. They navigate skinny branches on two feet, grabbling higher branches with their hands to help with their balance. They can also walk two-footed on the ground.
The paper in Science not only challenges the conventional wisdom that humans evolved from a four-footed terrestrial ancestor, it puts forward the simplest explanation yet for why we put one foot in front of the other.
Early humans didn't start walking upright so they could wade into water to find food, more easily carry their babies or travel more quickly and efficiently on the savannah, Dr. Crompton says, dismissing competing theories about the evolution of bipedalism.
Instead, they learned how to walk in trees, and eventually did the same on the ground.
"Bipedalism is nothing new. It is not the dramatic change that people portray it as," he says.
He has long been skeptical of the theory that humans originally walked like gorillas, and over time came to use two feet and stand upright.
Studying orangutans offered a chance to gather evidence for an alternative explanation. His colleague, Susannah Thorpe at the University of Birmingham, spend a year in the Sumatran rain forest recording almost every move the orangutans made.
The team concluded that two-footed walking helps orangutans survive because it allows them better access to fruit.
They argue than ancient apes - including our ancestors - probably did the same thing, and that upright walking offered an advantage once they climbed down from the trees.
Starting about 24 million years ago, the rain forests in East and Central Africa dwindled and became patchy. Apes that had spent almost their entire lives in the forest canopy had to walk from tree to tree.
Early human ancestors probably spent more time feeding on the forest floor, the researchers say. Compared to balancing on a springy branch, walking on the ground would have been easy.
The ancestors of chimps and gorillas, on the other hand, became more specialized at going up and down trees - holding on with both their hands and feet. They kept that same posture on the ground, which is why they often knuckle-walk, supporting their weight with their hands as well as their feet.
Paul O'Higgins, a researcher at the University of York in Britain, says the paper offers "compelling new evidence" that two-footed walking is more ancient than scientists ever imagined.
Not only can orangutans do it, but a number of fossils suggest that ancient apes were walking on two feet long before humans evolved.
These fossils show evidence of upright posture and bipedalism, Dr. O'Higgins says, but scientists weren't sure what to make of them.
The new research offers an explanation: ancient apes could walk upright.
But it also complicates the work of paleontologists, who have used evidence of two-footed walking as a key criterion for distinguishing early human (or hominin) fossils from those of other apes.
"It turns it all on its head, and reopens the debate," he says. "The key question is; how do we recognize our own ancestors?"
We may have always walked upright
A team of scientists says our ancestors may have always walked upright, but in trees, much like orangutans do. Early humans were able to transfer that skill to the ground. But the ancestors of gorillas and chimps stayed in trees longer, which is why their descendants use their hands and feet when walking.
Shared ancestor
This large ancestral ape was capable of hand-assisted, arboreal bipedalism with extended lower limbs.
Orangutans
hand-assisted bipedalism allows movement on slender, springy branches for easier crossings between trees.
Gorillas
and chimps, in response to changing habitats, moved in and out of trees, independently acquiring knuckle walking.
Chimpanzees
The bent-hip, bent-knee bipedal posture accomodates the physical demands of vertical climbing.
Hominins
retained the adaptations for extended-limb bipedalism and eventually became committed to walking on the ground.
SOURCE: SCIENCE MAGAZINE
easynash
Islam, eminently logical, placing the greatest emphasis on knowledge, purports to understand God's creation:Aga Khan 4(2006)
The God of the Quran is the One whose Ayats(Signs) are the Universe in which we live, move and have our being:Aga Khan 3(1952)
Our interpretation of Islam places enormous value on knowledge. Knowledge is the reflection of faith if it is used properly. Seek out that knowledge and use it properly:Aga Khan 4(2005)
