Biology

BIOLOGY, THE STUDY of life, has grown in complexity and comprehensiveness from its origins in antiquity. By the 20th century, biology was not a single science, but a group of subfields. Among the subfields was conservation biology, the discipline that sought to verify the reality of climate change and to stop it before it causes a mass extinction of species. In a number of ways, conservation is unique among the biological sciences. It is the science that is most conscious of global warming and of the need to arrest it.

Biology had its first stirrings among the ancient Greeks; Aristotle was the pioneer. The founder of anatomical studies, Aristotle likely performed the first dissections. His study of anatomy presaged the work of French comparative anatomist Georges Cuvier. Aristotle also appears to have been the first taxonomist. His classification of marine invertebrates anticipated the work of Swedish taxonomist Carl Linneaus.

As the founder of developmental biology, Aristotle sought to explain why, for example, an acorn always develops into an oak tree, and a frog's egg always turns into a frog. This line of research would lead to the 20th-century science of genetics. Aristotle sparked an interest in biology among his pupils, one of whom, Theophrastus, established the science of botany.

From this impressive beginning, the study of biology languished in the early Middle Ages, a period of theological, rather than scientific, study. In the 12th century, several universities in Italy revived the study of anatomy. Their focus was on human anatomy as a method of training physicians. The dissection of cadavers brought reproaches from the Catholic Church; but this work continued and, in 1543, Flemish physician Andreas Vesalius published his landmark study of human anatomy, The Fabric of the Human Body.

To an agnostic, the dissection of human cadavers implied that a person was nothing more than the sum of his or her parts: organs, muscles, bones, and the like. French philosopher and mathematician Rene Descartes wrote that purely mechanical forces animated the lower organisms. Humans alone had an immaterial soul. The idea that humans had a soul did not persuade everyone, and many biologists in the 20th century quietly banished the soul to the realm of superstition. Swiss alchemist Paracelsus had a more promising insight in supposing that chemical processes animated life. From this insight would emerge the science of biochemistry.

The 18th century was the age of taxonomy, one of Aristotle's lines of research. Among the systems of classification, Linneaus's work continues to influence the science of taxonomy. It was Linneaus, for example, who named humans Homo sapiens. Linneaus [Page 123]assumed that humans were special and deserved a genus apart from all other organisms. Natural theology, the study of nature for theological ends, agreed that humans were special among all other forms of life. The science of evolutionary biology, emerging in the 19th century, eroded the belief that humans were somehow special. Like all other organisms, humans were the result of natural selection, the product of nearly 4 million years of evolution.

Evolutionary biology requires that natural selection operate on a diversity of traits. Not all organisms of a species are identical; they vary in their particulars. Humans, for example, differ in height, eye and hair color, shape and length of the nose, and myriad other traits. The source of this variation puzzled British naturalist Charles Darwin, who was unaware of Austrian monk Gregor Mendel's work. Mendel was the first to understand that genes code for traits and that organisms differ because they have different assortments of genes. Mendel founded the science of genetics, which grew in scope during the 20th century.

...