Thursday, August 10, 2006
A Second Look at Walking Australopithecines and the Direction of Evolution
However, in the latest Journal of Creation, Matthew Murdock makes a case for Australopithecus walking upright on the basis of its pelvis rather than its feet. In particular Murdock uses muscle attachment evidence:
It is not only the shape of the pelvic bones that are important in locomotion, it is the attachment of the muscles. Abductors are pulling muscles that draw a body part away from the midsagittal line (midpoint or midline of the body), such as moving your arms outward, or spreading your legs apart. Quadrupeds have a gluteus maximus (muscle of the buttocks) that acts as an abductor of the thigh. In bipeds the ilium is expanded posteriorly, and the gluteus maximus originates behind the hip joint. So rather than abducting the thigh, it serves to pull the thigh back in one leg while the other is moving forward.
Both Lucy and Sts 14 have the posterior expansion of the pelvis that would allow the gluteu muscles to abduct the thigh in bipedal locomotion.
Both specimens (A.L. 288-1 and Sts 14) have a wide and thick ilium along with a long femoral neck which adds to the leverage the abductors can exert. The more leverage the abductors have the more efficient the creature can walk bipedally.
Murdock makes several additional points in favor of bipedality of australopithecines (if you want to know them all -- read the paper!).
As a side note, Murdock contrary to many creationists, Murdock puts homo erectus as an ape, rather than a human.
Murdock believes that australopithecus is an ancestor of modern chimps:
There are signs of degeneration in every bone of the chimpanzee body compared to an australopithecine. Every bone of the australopithecine body is more complex than a chimpanzee. There are differences in the skull, the vertebrae and the limbs that enabled the australopithecines to walk upright habitually, and which limits chimpanzees to walking upright only part of the time. When they do walk upright, they do so with knees and back bent slightly.
...[explains more interesting aspects of chimp walking]...
I will explore these differences and their implications at a later time, but can say that they all follow a degeneration pattern from biped to quadruped.
So Australopithecus could probably stand upright perfectly at first (in Eden for which we have no fossils) and then years later with difficulty, balancing as we see in Lucy (post-flood), and finally to what we now see today in chimps, which is habitual quadrupedalism, with only moments of awkward bipedality.
Murdock also commented that many of the problems in current human/ape paleontology come from coming to the data with the wrong assumptions. He says that the data, rather than pointing to australopithecus as an ancestor of humans, instead is like an ancestor of chimpanzees. Australopithecines are very much like a more complex chimp. The assumption that evolution is progressive is what prevents current paleontology from seeing the obvious patterns. As he says, "Nobody is looking for animals that are more complex than their living relatives in the fossil record (biblical view)".
Finally, he comments about the general relationship between australopithecines, humans, and chimpanzees:
Having studied not just the pelvis of australopithecines, but skeletons of three of them (two published, one unpublished), and comparing them with humans, other hominids and extant apes it is easy to see the similarities between australopithecines and chimpanzees. There are far more similarities than differences, whereas between ausstralopithecines and humans there are similarities yes...[description of dentition and pelvis]...but there are far more differences between the two.
Anyway, what I got most out of this article is:
- Pelvic evidence favors Lucy being bipedal (however, I don't think it's a closed case -- Wieland's complaints weren't addressed, but I think I can certainly agree that Lucy was better at it than modern chimps)
- Many of the problems in establishing phylogenies in evolution may stem from evolutionists looking at the wrong direction of evolution (this was also hinted at in a recent Science paper on prokaryotes/eukaryotes)
- I am now eagerly awaiting Murdock to expound upon his thesis that chimpanzees are devolved descendents of australopithecines
Murdock, Matthew. 2006. "These apes were made for walking: the pelves of Australopithecus afarensis and Australopithecus africanus". Journal of Creation 20(2):104-112.
Again, thanks for your support and your willingness to examine Creation and australopithecines in a new light.
Thanks for dropping by! I learned a lot in the paper not just about the australopithecine issue, but about paleontology in general. It was fabulous!
Looking forward to your next paper.
Stick around and enjoy the fun!