Introduction to Biology & Branches Of Biology

The physical world including all natural phenomena and living things is called nature.

The biologists study the living part of the nature.

Biology is a branch of science which deals with the study of living things.Or it is a branch of science which deals with the study of life.

“Life is a set of characters that distinguish living organisms from non-living objects (including dead organisms)”.

Cell, DNA and Metabolism are three basic characters of life. Other characters: Life is highly organized; complex; Homeostasis; get and use energy; growth; reproduction;response to stimuli.

Modern biologists believe that life had originated in oceans first and then migrated to the land.

About the origin of life, it is suggested that life must have begun with some simple cell. With the passage of time it evolved into the plants and animals of today.

If there is a spontaneous appearance of life, the beginnings must be due to by chance association of atoms.

It is believed that the primitive earth had an atmosphere of methane, ammonia, water-vapour, hydrogen sulphide and hydrogen. These simple substances gradually combined into complex molecules. From these complex molecules life was originated.

Unit of living/life is the cell. Unit of living and non-living is the Atom.

Living organisms are composed of one or more cells.

The application of the principles and methods of physics and the other physical sciences tothe solution of biological problems is the biophysics.

EXTERNALMORPHOLOGY is the study of form and structure of living organisms with the naked eye or with microscope.

INTERNALMORPHOLOGY(ANATOMY) is the study of internal gross structure.Or itis the study of internal organs of a dissected organism.

Histology is the microscopic study of tissues.

Cytology is the study of structure and functions of the cells.

Physiology is the study of normal functioning of various parts of plants or animals.

PALAEONTOLOGY is the study of fossils. Its two forms are: Palaeobotany the study of plant fossils. Palaeozoology the study of animal fossils.

Fossils are the remains of living organisms or their impressions preserved in the rocks.

Genetics is the study of hereditary characters transmitted from parents to the offspring’s.

Taxonomy is the naming and classification of organisms.

Classification means the arrangement of plants and animals into groups and subgroups according to their similarities.

EMBRYOLOGY is the study of the development of an organism from zygote.

A zygote is a fertilized egg.

EVOLUTION is the ancestral history of living organisms.

BIOGEOGRAPHY is the distribution of organisms in nature. Its two forms are: ZOOGEOGRAPHY the distribution of animals in nature. PHYTOGEOGRAPHY the distribution of plants in nature.

MOLECULARBIOLOGY is the study of structure of organisms, the cells and their organelles at molecular level.

ECOLOGY is the study of organisms in relation to their environment.

MICROBIOLOGY is the study of microorganisms which include Bacteria, Viruses, Protozoa, microscopic algae and microscopic fungi.

FRESHWATERBIOLOGY (Limnology) is the study of organisms living in freshwater bodies (i.e., rivers, lakes etc.) and physical and chemical parameters of these water bodies.

MARINEBIOLOGY includes the study of the marine life (life in seas and oceans) and the physical and chemical characteristics of the marine environment.

PARASITOLOGY is the study of parasites. The structure, mode of transmission, life histories and host — parasite relationships are studied in parasitology.

HUMANBIOLOGY deals with the study of morphology, anatomy, histology, physiology, evolution, genetics, cell biology and ecology etc. of human beings.

SOCIAL BIOLOGY: Study of social behaviour and communal life of human beings. Or The study of the biological basis of social behavior, or the study of behaviors from an evolutionary perspectives.

BIOTECHNOLOGY: Use of living organisms, systems or processes in manufacturing and service industries.

PATHOLOGY is the study of cause, origin and nature of diseases.