Bones Unearth Faculty Interest
A new female skeleton belonging to the same species as the famous Lucy was discovered in Ethiopia this September. While Lucy was an adult skeleton, this one is a juvenile, which scientists hope will help provide a more detailed snapshot of ancient hominid life. For this article, Oberlin professors of anthropology, geology and biology weighed in on how the discovery has affected their fields of study.
Scientists from the Max Planck Institute for Evolutionary Anthropology in Leipzig reported the unearthing of the hominid skeleton at the end of September in an exposed portion of a sedimentary. Geologists aged the exposed portion at 3.3 million years, which places it in the Pliocene age. Based on structural comparisons with previous fossil finds, the skeleton is thought to belong to the species Australopithecus afarensis, the same classification as Lucy — found in the same region in 1973.
Remarkably complete, the remains of the new find include the skull, many bones of the trunk, parts of both legs and one foot. The structure of the limbs suggests that the individual was bipedal, like Lucy, but curved bones of the fingers and gorilla-like morphology of the scapula, or shoulder blade, suggest to anthropologists that the individual may also have climbed trees.
Professor of Anthropology Linda Grimm is an archeologist specializing in human evolution. Grimm said that the finding is “important because it’s a young individual [which is a rarity]. Unlike most fossils, it’s amazingly complete.”
“[The finding] confirms so much of what we have come to believe about Lucy,” she added, giving as examples the combination of features for terrestrial and arboreal life.
Karla Parsons-Hubbard, a Professor of Invertebrate Paleontology, also marveled at the completeness of the preserved skeleton. In order to be protected from scavengers and weathering events, she said, the corpse must have been preserved in sediment soon after death and in a manner that did not damage the fragile bones of the young specimen.
A variety of scientific bodies of knowledge and methods of inquiry were brought to bear on this finding, including anatomy and physiology, geology, paleontology, analyses based in chemistry and physics and multiple branches of anthropology — all under the umbrella of the study of evolution.
Evolution is a topic studied by scholars in many fields outside biology, and the approaches to studying evolution can be quite varied. For example, Biology Professor Yolanda Cruz is a developmental biologist who seeks primarily molecular explanations for developmental phenomena. For Cruz and many biologists, definitive evolutionary relationships can be drawn only from analysis of DNA sequences. These have not been extracted from the hominid specimens in question.
Other attempts at classification, such as paleontology, remain largely speculative until molecular evidence can provide a clear answer.
In this case, the molecular evidence is not available and would not be particularly useful for making judgments about evolution even then.
“It is unlikely that many interesting changes visible at the level of sequenced DNA could have occurred between Lucy’s time and ours,” said Cruz. “Dinosaurs and people, yes, but not among primates.”
This is not to write off the discovery, but just to say that it is outside of the domain in which she studies evolution.
Cruz said that she had “heard of this discovery, and was excited by it, but [that] it really doesn’t touch ‘evo-devo’ [evolutionary developmental biology] in the sense that I know or teach about it. Development and evolution intersect across many millions of years, and not within a species and only rarely among closely related species only a few million years apart.”
For paleontologists and anthropologists like Professor Amy Margaris, on the other hand, “Fossils are a critical kind of evidence that can offer insights into hominid evolution and adaptations that complement those made by genetics — and with the added bonus that physical anthropologists are trained to take culture into account, something critical to our evolution as a species.”
Margaris provided an example of a physiological insight outside the realm of genetic analysis: “The preserved anatomy, such as of the scapula and finger…gives unique clues about the animal’s locomotor abilities that genetic data probably could not tell us.”