We can simply define biology as the study of life. It is one of the natural sciences that deal with the studying of life and living organisms; including the growth, reproduction, evolution, function, classification and organization of every living creature in the earth. Those creatures are not limited to what is currently existing but also to the extinct ones and even to the prediction of future species that may occur.
The term biology is derived from two Greek words bios, which means "life" and logos, which means "study of".
Biology means the scientific study of the life and structure of plants and animals. The science that deals with the study of living objects goes by the general name of biology. Bios means life and logos means discourse or study. Since both animals and plants are living, biology includes a study of both. Biology is, therefore, divided into two branches: botany (botane, plant) which deals with the study of plants from many point of view with internal and external structures of all kinds of plants from the simplest to the most complex form, and zoology (zoon, animal) which treats of animals.
Biology is made up of two roots, bio and ology. Bio means life, and ology means the study of. Hence, the definition of biology means the study of life. With expanding knowledge of biology, biology studies may involve study the chemistry of living organisms and aspects that involve living organisms. Biology also involves the studies of systems, microsystems and macrosystems. Hence, in learning biology one could learn about the working of a system of a small cell, to a bigger system of the human body, to the system of an environment in which organisms thrive. Furthermore, in the study of biology include learning major topics of biology, such as evolution, ecology, genetics, physiology, and cell biology.