evolving through time. Consider the Arctic, which was widely colonized after about 1,500 years ago by people who invented dog sleds, whale-hunting equipment, watercraft, and the snow-house or iglu.
This purposive invention leads us, I think, to see living things the way we see our artifacts: as the finished products of some kind of intent. It’s hard to imagine that some mind didn’t make the elm tree for some purpose, because we ourselves invent and build things for specific purposes. But evolution shows that those things can come to be without any conscious plan or designer. That can be hard to reconcile with humanity’s purposeful tendencies.
More facets of physical anthropology
The evolutionary principles underlying physical anthropology touch everything that physical anthropologists study. In this section, I outline a few of the main fields of physical anthropology; you can read about yet more subfields and discoveries in the other chapters in this part of the book.
Primatology
One specialty of physical anthropologists is the study of living primates, a field called primatology. (Some biologists also study primates, but without expressly looking for what they can teach humanity about itself.) Primatological physical anthropology studies primate behavior, biology, evolution, and anatomy. Each of these fields ties into the other, such that what anthropologists learn about behavior informs — and is informed by — what they learn about biology and so on. For example, you can’t fully understand the anatomy of a species without knowing about its evolution because anatomical characteristics — like a prehensile tail, or new kinds of teeth — don’t just pop up out of nowhere; they accumulate (or vanish) as selective pressures change and shape the organism.
Anthropologists study primate behavior by using the principles of ethology, the study of animal behavior. Although approaches vary, they often emphasize
Observation of the animal in its natural environment for long periods — for example, across seasons and years rather than just a few weeks at a time
Careful consideration of the interplay between behavior, environment, and anatomy, accounting for all that’s known about the species
A search for and explanation of widespread similarities of behavior
A search for and explanation of differences of behavior
Unfortunately, study of many primates in their natural habitats is becoming impossible as primate species become extinct or their habitats are reduced. (You can read more about the peril in which many primate species exist in Chapter 4.) Unfortunately, primatologists must often resort to studying primate species in enclosure settings such as zoos (where their behavior and biology must differ from that in the wild). Considering that humanity has only been doing comparative primatology for a few decades and is only just sketching out an understanding of the living primates, this situation is a real shame.
Paleoanthropology
Paleoanthropology (paleo meaning “old”) specifically studies the human species and its relatives in the ancient past, particularly focusing on the early proto-human species, known as the hominins. (You can check out more on hominins in Chapter 6.) Paleoanthropology is extremely diverse and involves finding ancient human fossils, excavating them (and any artifacts found with them, including stone tools), interpreting the skeletal remains to understand the anatomy, and reconstructing hominin behavior as well as evolutionary relationships. To accomplish all this, most paleoanthropologists have a strong background in the following fields:
Evolution: Because the foundation of biology must be comprehensively understood to make sense of the fossil record
Skeletal anatomy: Because fossilized bone (bone turned to stone by a geochemical process) is the bread and butter of paleoanthropology, understanding how the body’s skeletal tissues reflect daily life, disease, stress, and other factors is critical to reconstructing ancient ways of life
Geology: Because fossils are often found in complex geological circumstances, such as fossil beds that contain the fossils of lots of plants and animals, perhaps millions of years extinct
Archaeology: Because archaeologists must exercise great care to excavate fossils, the principles of keeping track of where they find items and carefully bringing them back to the lab are important
Some people even specialize within these divisions; some paleoanthropologists focus on certain parts of the skeleton (like the teeth, the hand bones, or the pelvis), some focus on specific geological layers (for example, layers representing time before or after some event), and some focus on paleoecology, reconstructing entire ancient ecosystems in which early hominins evolved.
One of the main contributions of paleoanthropology to the human understanding of humanity is to fill in the missing links of the evolutionary chain connecting modern people to our most ancient ancestors. Unfortunately the term missing link is something of a misnomer because species aren’t so easy to define or draw lines around when you know them from fossil material only. But fossils do tell a lot about ancient life, and they do indeed show us, as a species, where we’ve been both figuratively and literally. (You can read more about fossils in Chapter 6.) Today, hundreds of fossil specimens bear some resemblance to modern people, and more ancient human-like forms. Because new species don’t pop up out of nowhere today, anthropologists can reasonably assume that these hundreds of fossils don’t represent early proto-humans that simply popped up and then vanished, either. Instead, they represent members of our own lineage that slowly changed over time by the evolutionary process. Fossil specimens are better thought of as shades from an evolutionary spectrum than links in a chain, but the chain metaphor has stuck, and it’s a tough one to fight.
THE KOOBI FORA RESEARCH PROJECT
Just two years into my undergraduate study of archaeology, I was lucky enough to participate in a field school at the Koobi Fora research project in northern Kenya. Run from the National Museum of Kenya and based on a landform called Koobi Fora on the eastern shore of Lake Turkana (once Lake Rudolf), the project was begun by Richard Leakey in the 1960s. Later it was run by his daughter, Dr. Louise Leakey.
Decades of research at Koobi Fora have revealed more than 200 early hominin fossils dating between about four million and 700,000 years ago. As a student, I vividly remember crawling across the baking desert and finding chips of stone eroding from an ancient lake-shore; picking one up, I realized it had been buried for more than a million years, and my career was locked in that moment.
Currently, George
