Up until today, the best known ancient ancestor of ours has been the Australopithecus afarensis known as Lucy, more than a million years younger than Ardipithecus. A. ramidus was different from Lucy, different from modern apes and different from modern humans, in that he moved differently, had a mobile lower back and a robust and flexible hand structure.
Researchers have believed since the discovery of Lucy that both extant African apes and hominids evolved from a transitional ape-like ancestor, but the investigation of Ardipithecus ramidus suggests that the anatomy of living African apes—including knuckle walking, vertical climbing and suspension behaviors—evolved after the hominid line broke away from them. In other words, the anatomy and behavior of hominids has deeper roots than scientists believed even as short a time ago as 15 years.
According to researcher Owen Lovejoy, the discovery of such a fully bipedal, upright hominid with a small cranium and upright pelvis, who lived in a wooded area and walked on the ground and in trees suggests a range of behaviors. These behaviors—food-carrying, pair-bonding and reduced advertisement of ovulation—all would have intensified male parental investment. That adaptation, says Lovejoy, seems to have marked an evolutionary pattern which created the differences between apes and humans.
Sources and Further Information
Lovejoy, C. O., et al. 2009 The Great Divides: Ardipithecus ramidus Reveals the Postcrania of Our Last Common Ancestors with African Apes. Science 326:100-106.
Lovejoy, C. O. 2009 Reexamining Human Origins in Light of Ardipithecus ramidus. Science 32674e1-74e8.
- Ardipithecus ramidus, the blog post, which has links to recent news stories
- Lucy, famous Australopithecus afarensis
- Hominin
- Aramis, Ethiopia
- Bipedal locomotion
- Stable Isotope Analysis
- Phytoliths
- Middle Awash
