Introduction to Biology

(b) Study of living organisms, their structure, function, growth, evolution, and interactions

Biology is the branch of science that deals with all aspects of living organisms — their form, physiology, development, origin, evolution and their relationship with one another and with the environment. Options (a) and (c) cover only animals and plants respectively, while (d) describes chemistry, not biology.

Biology is the branch of science that deals with the study of living organisms — their structure, function, growth, origin, evolution, distribution, and the interactions among themselves and with their non-living environment. The word is derived from the Greek words bios (life) and logos (study), so biology literally means "the study of life."

The major branches of biology include:

1. Morphology — the study of the external form, shape, size, colour, and structural features of organisms. It is divided into external morphology (study of outer features) and internal morphology or anatomy (study of internal organs). For example, the study of the shape of leaves, roots, and flowers of a plant.

2. Anatomy — the study of the internal structure of organisms, i.e., the arrangement and relationship of internal organs and tissues. For example, the study of the arrangement of the heart, lungs, and digestive organs in the human body. Its sub-branch histology deals with tissues.

3. Physiology — the study of the normal functions and life processes of living organisms and their organs, such as digestion, respiration, circulation, excretion, and reproduction. For example, studying how the human kidney filters blood to form urine.

4. Taxonomy (Systematics) — the branch of biology dealing with the identification, naming, classification, and study of the relationships of organisms. It arranges organisms into groups such as kingdom, phylum, class, order, family, genus, and species. For example, classifying humans as Homo sapiens.

Other important branches include cytology (study of cells), genetics (study of heredity and variation), ecology (study of organisms in relation to their environment), and embryology (study of the development of the embryo).

Importance of Biology

Biology is the study of living organisms, and its principles and techniques are applied in many fields that directly affect human welfare. Its importance in four major fields is described below.

1. In agriculture

• Biology helps in understanding the structure, physiology, and genetics of crop plants and livestock.
• Improved high-yielding, disease-resistant, and pest-resistant varieties of crops have been developed through plant breeding, hybridization, and genetic engineering (e.g. hybrid maize, disease-resistant wheat).
• Biofertilizers (Rhizobium, Azotobacter, blue-green algae) and biopesticides (Bacillus thuringiensis) are used to increase soil fertility and control pests without harming the environment.
• Tissue culture and cloning are used to produce large numbers of disease-free plants in a short time.
• Knowledge of plant and animal diseases helps in their prevention and control, and of animal nutrition and breeding in improving milk and meat production.

2. In medicine

• The study of anatomy, physiology, and microbiology is the basis of diagnosis, treatment, and prevention of diseases.
• Vaccines (e.g. for polio, measles, hepatitis, COVID-19) and antibiotics (penicillin) have been developed through biological research, saving millions of lives.
• Techniques such as X-rays, ECG, MRI, organ transplantation, blood transfusion, and kidney dialysis depend on biological knowledge.
• Biotechnology has made possible the production of human insulin, growth hormone, and interferon using bacteria, and gene therapy for genetic disorders.
• It also helps in understanding the causes and inheritance of genetic diseases and in family planning.

3. In the environment

• Biology helps in understanding ecosystems, food chains, and the interdependence of organisms.
• It explains the causes and effects of pollution, deforestation, soil erosion, and loss of biodiversity, and suggests remedies.
• Biological knowledge is used in waste treatment (sewage treatment plants, biogas production), bioremediation of polluted soil and water, and conservation of endangered species.
• It creates awareness about the need to maintain ecological balance for the survival of mankind.

4. In industry

• Biology is applied in the production of fermented products such as curd, cheese, bread, beer, wine, and vinegar using microorganisms.
• Antibiotics, vitamins, enzymes, organic acids (citric acid, lactic acid), and alcohol are produced industrially by microbes.
• Biotechnology industries produce genetically modified organisms, biopolymers, and biofuels.
• The leather, dairy, food processing, and pharmaceutical industries all depend on biological principles and processes.

Conclusion Thus, biology is not merely a theoretical science but an applied science whose knowledge is essential for food production, health care, environmental protection, and industrial development.

Living beings are organised, self-regulating systems of matter that carry out metabolism, respond to stimuli, grow, reproduce and evolve. They are made of cells, use energy and maintain a constant internal environment. Non-living things lack these capacities, though they may show isolated features (a crystal "grows", a river "flows").

Major characteristics distinguishing living from non-living things

1. Cellular organisation: All living things are made of one or more cells, the basic structural and functional units. Non-living matter is not cellular.
2. Metabolism: Living things carry out anabolism and catabolism with exchange of energy. No non-living object metabolises.
3. Growth and development: Living organisms grow from inside by increase in cell number and size and pass through definite stages. Non-living things grow only by external accumulation.
4. Reproduction: Living organisms produce offspring of their own kind (sexually or asexually), keeping the species continuous.
5. Response to stimuli: Living beings sense and react to physical, chemical and biological stimuli, such as the touch-me-not (Mimosa) leaf folding or phototropism.
6. Movement: Living organisms show movement of protoplasm and often locomotion. Non-living objects move only when pushed by an external force.
7. Respiration and excretion: Living beings release energy by oxidation of food and remove metabolic wastes.
8. Homeostasis and organisation: Living things maintain a stable internal environment and a definite organisation from molecules to organs.
9. Adaptation and evolution: Populations adapt to their environment and change genetically over generations.
10. Life span: Living organisms are born, age and die.

Significance of biology in modern society

• Health and medicine: Vaccines, antibiotics, insulin, organ transplantation and control of diseases such as TB, polio and COVID-19.
• Agriculture and food security: Improved crop varieties, hybrid seeds, biofertilisers, biopesticides and tissue culture.
• Biotechnology and industry: Genetic engineering, fermentation and enzyme technology produce medicines, foods and chemicals.
• Environment: Ecology and biodiversity studies help in pollution control, wildlife conservation, forest management and tackling climate change.
• Forensics and law: DNA fingerprinting and serology help in crime investigation.
• Animal husbandry: Better breeds raise milk, meat and egg production.
• Employment and economy: Careers in medicine, pharmacy, agriculture, biotechnology and research.
• Scientific outlook: Biology explains the origin and diversity of life and promotes rational thinking.

(b) Taxonomy

Taxonomy is the science of identification, naming (nomenclature) and classification of organisms into groups. Morphology studies form and structure, ecology studies relationships with the environment and histology studies tissues.

(b) Mycology

Mycology is the study of fungi (Greek mykes, fungus). Phycology deals with algae, bryology with mosses and virology with viruses.

(b) Carolus Linnaeus

Linnaeus introduced binomial nomenclature in Species Plantarum (1753), naming each organism with a genus and a species name.