The Science Of Physical Anthropology
When oceans formed on the newly solidified surface of planet Earth more than 3. 5 billion years ago, the conditions were met for the first seeds of the roots of the tree of life to grow. The nutrient rich liquid, lacking in predators of any kind, provided the perfect environment for the development of simple microorganisms. For billions of years, the single celled organism ruled the world, participating in a slow process of evolution. Working together, these single celled organisms could accomplish a more complex and effective existence and propagation leading to the first multicellular organism 900 million years ago. The resulting explosion in quantity and variety of multicellular life sparked further evolution, bringing life on Earth to the state it exists in today. Contrary to what some believe, human life on Earth did not spontaneously appear. We’re too complex, our bodies composed of millions of organisms existing in harmony to produce one complete living being with thoughts and feelings. Just as the first organisms banded together to become more complex, so too has humanity - there is evidence of a rich history of physical and cultural evolution. Just as a baby becomes a young girl who becomes a teenager who becomes a woman, so too has humankind matured and developed to where we are today. As humans, the study of the origin and evolution of humankind is a subject of great curiosity.
Physical anthropology deals with the study of this increasing complexity of life, specifically as it relates to human evolution. Through the use of various forms of collected evidence, anthropologists seek to know where we come from, how we got where we are today, and where we are growing towards. There are four major fields of anthropology: biological anthropology, cultural anthropology, linguistic anthropology, and archaeology. Each focuses on a different set of research interests and generally uses different research techniques.
Certain types of rock formation allow for the study of organisms from eras long past. Wind, moving water, and even glaciers transport matter along the surface of the planet, depositing sediment which eventually solidifies to form sedimentary rock, one of the tools of the anthropologist. Due to the nature of the formation of sedimentary rock, the petrified remains of early proto-human organisms can be found in stone. These impressions are called fossils, and are particularly useful to biological- and paleoanthropologists. Fossils are formed when an organism dies in a watery or silt rich environment; though soft tissue usually decomposes quickly, the skeletal remains of the organism endure. The silt and sediment carried by various means fall on the final resting place of the dead organism and overtime compact into a sedimentary rock. The result is a perfect impression of the skeleton of the organism, trapped in stone. When discovered, these fossils are useful for a number of reasons; for instance, accumulation of fossils has allowed scientists to construct a timeline of evolution backed by physical evidence, known as the fossil record.
Fossils are found when sedimentary rock is exposed, which researchers will excavate. Many are found accidentally by miners, scientists, even natural exposure. Once discovered it has to be dated to fit into the fossil record. Key to the construction of an accurate timeline in modern archeology is stratigraphy, the study of the order of strata. Strata are layers of sedimentary rock with characteristics which distinguish it from other layers; through examination of these characteristics, the rocks, and thus the uncovered fossil, can be approximately dated through radioisotope dating of igneous rocks near the discovery. Unstable elements, such as Uranium-235, have a predictable half-life; analysis of how much a given a isotope remains reveals it's age. Unfortunately, the fossil record isn’t a perfect recording of the evolutionary history of humanity. The conditions for the creation of a fossil are specific - an organism has to die in a location capable of preserving fossils, it has to be covered before the body is destroyed or eaten, it has to survive or luckily avoid any number of catastrophic events which could destroy the fossil, and then it has to be discovered by someone who understands the importance of what they found.
Many fossils have likely been destroyed by nature and ignorant or uncaring human hands. Because of the high threshold for the creation of a fossil the fossil record is spotty at best, rarely showing a complete evolutionary path. There are many gaps in the search for evidence of human evolution which may never be filled by physical fossil evidence. However, studying the fossilized and otherwise preserved remains of human bones and teeth has led to great strides in the study of the physical form and structure of an organism - known as morphology. Though the record is incomplete, a somewhat clear evolutionary path can be exposed. Due to our bipedal nature humans have the most distinct feet of any primate, as we need feet which can accommodate the entire weight of our body on one foot at a time. To that end, human evolution resulted in an adducted toe bone which helps us walk upright. By understanding the physical process of bipedalism, anthropologists can search the fossil record for evidence of the origins of bipedalism in primates, helping us identify human ancestors. Anthropometers are used to measure human bones, and spreading calipers are used to measure head length and breadth. Teeth are studied to great effect as well. Measured with boley gauges, they are easily identified as human or ape, and can be used by anthropologists to estimate how old the remains are, the diet consumed by the human, an analysis on the health of the human, and can even point towards cultural rituals. More than just human remains, anthropologists also study the surrounding material found at sites.
Artifacts are the man made products of people from the past, and can include clay pottery, bricks, clothing - basically anything a human has made. Examination of artifacts left behind by past humans can reveal much. Anthropologists can learn about the aesthetics of a group of people from their clothing and adornments on other items. The makeup of the artifacts can point towards information about the artisan techniques or materials available to them. Correlation between other sites can show how cultures traded and interacted, showing their routes and migration patterns. By seeing what they left behind, we can figure out what they valued as a group. Just as important as the things intentionally carried by people are those things unintentionally carried. Ecofacts are the environmental remains which were minimally or not at all altered by humans. A common ecofact is plant or seed remains, which can be used to discern information such as diet and medicine. Pollen can be linked to a specific type of plant, and if enough is found, this can point towards the cultivation of plant life, and what types of plants they cultivated, providing information on their way of life. Utilizing new technology, genetic anthropologists use gene data and DNA testing in the study of human evolution to find patterns of human variation, relationships between humans and primates, the migration of humans, and relationships between biological variation and other types of variation, such as language. Through genetic testing, it was discovered that physical variations of groups of people, such as height, complexion, and hair color, are the result of the complex hereditary actions of genes. Through examination of data recovered through DNA testing, anthropologists discovered physical adaptations born from differing environments of humans. Information such as this can point towards the migratory habits and evolutionary past of groups of people.
Anthropologists seek to uncover the mysteries of human history, the history of all life on this planet, as all life has common ancestry. They want to know where we came from, where we traveled, the culture of the people who came before us, the environments people lived in and why they made those choices. Through examination of the choices and lives of people of the past, anthropologists pursue a more complete comprehension of the forces which drive humankind towards whatever ambition we are eventually headed for.
