Our universe operates under certain principles. For understanding of these principles, the experiments are done and observations are made; on the basis of which logical conclusions are drawn. Such a study is called “Science”. In brief science is the knowledge based on experiments and observations.
The Scientific study of living organisms is called Biology. The word biology is derived from two Greek words “bios” meaning life and “logos” meaning thought, discourse, reasoning or study. It means that all aspects of life and every type of living organism are discussed in biology.
Branches of Biology
Biology is divided into following branches:
The study of form and structure of living organisms is called morphology. It can be further divided into following two parts:
1. The study of external parts of living organism is called external morphology.
2. The study of internal parts of living organism is called internal morphology or anatomy.
The study of cells and tissues with the aid of the microscope is called Histology.
3. Cell Biology:
The study of structure and functions of cells and their organelles is called Cell Biology.
The study of different functions performed by different parts of living organism is called Physiology.
The study of organisms in relation to each other and their environment is called Ecology or Environmental Biology.
Living organisms are classified into groups and subgroups on the basis of similarities and differences. This is called classification Taxonomy is that branch of biology in which organisms are classified and given scientific names.
The study of development of an organism from fertilized egg (zygote) is called embryology. The stage between zygote and newly hatched or born baby is called embryo.
The study of methods and principles of biological inheritance of characters from parents to their offspring is called genetics.
The body parts of ancient organisms or their impressions preserved in rocks are called fossils. The study of fossils is called paleontology. It also includes the study of origin and evolution of organisms.
It can be divided into two parts:
1. The study of fossils of plants is called Palaeobotany.
2. The study of fossils of animals is called Palaeozoology.
The study of metabolic reactions taking place in living organisms is called biochemistry. These reactions may be constructive or destructive. The assimilation of food is a constructive process and respiration is a destructive process.
It is the branch of biology which deals with the practical application of organisms and their components for the welfare of human beings e.g. disinfections and preservations of food, preservations of insulin and biogas from bacteria etc.