Zoology

Zoology is the scientific study of animals. Its subjects are highly diverse, and it includes a wide range of other disciplines. Some of these study the whole animal in a very broad way, such as animal ecology, while others examine animals on a smaller scale, such as their anatomy (structure) or physiology (function).

Zoology is one of the two main branches of biology. The other branch of biology is botany or the study of plants. Zoology includes the study of every type of animal, from the 180-ton blue whale to the one-celled bacteria. Animals make up the largest of the five kingdoms that were created by biologists to organize and describe the living world. Besides animals, the other kingdoms are monerans, protists, fungi, and plants. Described in the simplest way possible, animals are multicelled organisms that move about and live by taking in food. They are classified into two main groups: vertebrates have bony internal skeletons and invertebrates do not. There are eight different groups, or phyla, of invertebrates, all of which differ greatly in body structure, where they live, and how they reproduce. Vertebrates all belong to the same phylum and are classified as cold-blooded (the internal body temperature changes with the environment) or warm-blooded (internal body temperature remains the same despite the environment). Finally, animals react to what goes on in their environment. Much of this behavior involves communicating with other animals, and searching for food, mates, and a place to live.

As a science, zoology began with the Greek philosopher Aristotle (384–322 b.c.), who developed his own system to classify animals. His accomplishments and reputation were so great that much of what he wrote about animals remained unquestioned for nearly 2000 years. It was not until the middle of the eighteenth century that a modern system of classifying animals was created by the Swedish botanist, Carolus Linnaeus (1707–1778). Another century would also pass before biology, and therefore zoology, would be given a theory of evolution (the process by which living things can change over time) to explain the origins and development of animal life. That great theory, published in 1859 by the English naturalist Charles Robert Darwin (1809–1892), laid a new foundation for zoology.

Since the nineteenth century, the field encompassed by zoology has grown so large that it eventually became divided up into many other fields or branches. Some of these are broad subject areas, like embryology, which studies the development of individual animals, and anatomy that studies the structure of an animal's body. Other branches focus on only one type of animal, such as ichthyology, which studies fish, or entomology, which studies insects. There are also other fields in zoology that focus only on animal behavior.

Technical advances have always played a major role in the advancement of science, and they have allowed zoology to progress rapidly as well. Beginning with the seventeenth-century invention of the microscope, zoology benefitted by the new ability to see not only tiny life forms but also smaller details of other animals that had not been known. Further improvements allowed zoologists to examine animals at their cellular level. Recent breakthroughs in gene technology have given zoologists the ability to manipulate an animal's genetic makeup for a number of scientific and commercial purposes. Zoological research benefits humans in many ways, one example of which is the use of bacterial studies to learn how to protect people from being infected by disease. Since cattle and chicken are key to humans' food supply, zoologists regularly search for ways to produce healthier animals. Finally, zoologists also work to preserve those animal species that are endangered and could possibly go extinct.