BIOLOGY

Biology(bios,life;knowledge) is a science devoted to the stdy of living organisms.Science has progressed by breaking down complex subject of the study into their component parts so that to day there are numerous branches of biology.Some of which are:

This principle is often called the 'reductionist' principle and carried to it's logical conclusions,it has focused attentation on the most elementary form of matter in living and non living systems.This approach to study seeks fundamental understanding by looking at parts rather,than the wholw.An opposing approch,based on the 'vitalist'principle,consider that 'life' is something special and unique, and maintains that life cannot be explained solely in terms of the laws of physica and chemistry,having properties which as special to the system as whole.The aim of biology must ultimately be to explain the living world in terms of scientific principles,althoug appreciating that organisms behave in ways which often seem beyond the capabilities of their component parts.Certainly the consiciousness of living organisms cannot be described in terms of physics and chemistry even though the neurophysiologist can describe the working of millions of neurons and their electro-chemical states,but as yet we have no real concept of the chemical nature of thoughts and ideas.Nor do we understand completely how living organisms originated and evolved.These have been many attempts to answers this questions from theological to biological,but with the emphasis on the possible biological explanations.
Thus we are reduce to the position that we cannot define precisely what life nor whence it came.All that we can do is describe the observable phenomena that distinguish living matter from non-living matter.These are as follows:

Nutrition:All living organisms need food,which is used as a source of energy,and materials for the process of life,such as growth.Only two sourcs of energy are used by living organisms,namely light and chemical energy.