In this video Emerald Robinson explains the definition of biology and the basic principles of Modern biology. Biology is the study of all aspects of life. Every living thing is studied in this vast subject from the nucleus of the tiny living cell to vast algal blooms spread over the surface of oceans. Scientists who study biology are called Biologists. Biology is a very broad science. Some scientists claim that there are over 50 branches of biology. There are 5 basic principles which unify all fields of modern biology. Since biology is a science, biologists use scientific method that is a specific series of steps designed to form answers to questions when doing experiments.