9 Chapter 9: How Did We Get Here?
I vividly remember my anthropology professor explaining how Raymond Dart is credited with discovering the first Australopithecine in South Africa 1924— a strange primate that walked on two legs some 3 million years ago. Technically, the real discoverers were miners who were instructed to bring anything strange they found to Dr. Dart’s attention during the course of their excavations. After explaining the discovery of the Taung Child as it is called, my professor changed his tone to storytelling mode. Dart wanted to make casts of the spectacular “career-making” fossil in England just in case something catastrophic happened to the actual remains. Dart was unable to go to London at the time, so his wife Dora was responsible for transporting the Taung Child to the lab in London. After arriving in the city, Dora took a cab to her hotel, but accidentally forgot the box with the skull in the backseat of the cab. The Taung Child then got a whirlwind tour of London. Eventually, the taxi driver discovered the box with the skull, assumed it was the head of a baby, and immediately called the authorities. My professor ended the story abruptly by stating that Dart and his wife divorced soon thereafter.
Paleoanthropology
Paleoanthropology is a specialized field in biological anthropology that is interested in human origins. This subject is investigated through two main avenues—the study of ancient fossils and genetics. Paleoanthropologists group ancient species into taxonomic groups (just like modern primates are classified in taxonomic groups) according to their morphology and sometimes their genetic makeup. This is done in order to understand the evolution, or change over time, in the human species.
Fossils are simply the remains of once-living organisms, whose tissues (usually bones and teeth) have been replaced by rock. Fossils only form when the organism was quickly buried and conditions are ideal. As a result, the fossil record represents only a small fraction of the populations that were once living. Paleoanthropologists also group species based on their genetics. This approach is only possible when tissues have not been fully mineralized or fossilized. This sparsity of the fossil record and the lack of preserved genetic material makes paleoanthropology a challenging discipline.
The processes by which species diversify today, as seen in the rock pocket mouse example, were also at play in the past. Mutations occur randomly and processes like natural selection and founder effect lead to diversification in species. These processes can lead to many branches that derive from a common ancestor. Change over time does not happen in a linear step-wise fashion, but rather in a branching fashion. In this chapter, we will look at some of those species that are thought to be ancestral to humans and why they are considered to be in the human family.
The Problem of Time
It was once thought that there wasn’t much time for a lot to happe