Introducing Biology Chapter Notes | Biology Class 9 ICSE PDF Download

Growth of Biology

• Biology began with early humans learning about plants and animals while gathering food and hunting.
• Prehistoric cave drawings of animals and plants show early human interest in living things.
• As humans settled into communities and started farming, they domesticated animals like dogs, cows, sheep, horses, and buffaloes, increasing their knowledge of animal behavior.
• Greeks were among the first to study biology systematically.
• Aristotle (384-322 B.C.) is known as the "Father of Biology" for his detailed study of animals.
• Theophrastus (370-285 B.C.) is called the "Father of Botany" for his work on plants.
• Hippocrates (460-377 B.C.) is recognized as the "Father of Medicine" for his contributions to healing and treating illnesses.
• In ancient India (2500 B.C. to 650 B.C.), animals and plants were classified into groups like Jeevaj (viviparous, giving birth to young ones) and Andaj (oviparous, laying eggs).
• India was the first to cultivate rice, developing over 1,000 varieties.
• The invention of the microscope in the 16th century revealed tiny organisms and cells, boosting biological discoveries.
• In the 19th century, biology advanced with discoveries like germs, the theory of evolution, and the cell theory.
• In the 21st century, biology continues to grow with advancements in vitamins, hormones, genetics, genetic engineering, antibiotics, cancer research, cloning, stem cell research, organ transplants, environmental sciences, and the search for life in outer space.
• Scientists are working on creating single-celled bacteria from non-living materials like fatty acids and nucleotides.

Branches of Biology

A. Based on Major Kinds of Organisms

• Botany: Study of plants.
• Zoology: Study of animals.
• Human Biology: Study of humans as living organisms and their interactions with other organisms.
• Anthropology: Study of humans and their societies.

B. Based on Special Groups of Organisms

• Bacteriology: Study of bacteria.
• Virology: Study of viruses.
• Mycology: Study of fungi.
• Entomology: Study of insects.
• Ichthyology: Study of fishes.
• Herpetology: Study of reptiles like lizards and snakes.
• Ornithology: Study of birds.

C. Based on Approach to Studying

• Anatomy: Study of the internal structure of organisms through dissection.
• Morphology: Study of the form and structure (both external and internal) of plants and animals.
• Histology: Study of tiny body structures using a compound microscope.
• Cytology: Study of the structure and function of cells.
• Physiology: Study of the functions and activities of organisms and their parts.
• Embryology: Study of the formation and development of embryos in plants and animals.
• Taxonomy (Systematics): Science of naming, grouping, and classifying plants and animals.
• Ecology: Study of organisms' relationships with their living and non-living environments.
• Biogeography: Study of the geographical distribution of plants and animals.
• Palaeontology: Study of prehistoric life through fossils.
• Evolution: Study of the origin and descent of organisms.
• Genetics: Study of how traits are passed from parents to offspring.
• Parasitology: Study of parasites that live on or inside other organisms and feed on them.
• Pathology: Study of diseases in plants and animals.
• Immunology: Study of immunity and resistance to diseases.
• Eugenics: Science aimed at improving the human race through controlled heredity.
• Biochemistry: Study of chemical reactions inside living organisms, including applications like DNA fingerprinting.

Applied Biology

• Agriculture: Growing crops and raising livestock like cows and buffaloes.
• Veterinary Science: Treatment and surgery of animals.
• Marine Biology: Study of life in the sea.
• Household Biology: Study of household animals and insects, including ways to prevent harm to humans and property.
• Horticulture: Science and art of growing fruits, vegetables, flowers, or ornamental plants.
• Sericulture: Technique of producing silk by raising silkworms.
• Pisciculture: Technique of growing fish.
• Molecular Biology: Study of biological events in terms of molecules in cells.
• Biotechnology: Use of living cells or microorganisms in industry and technology, including biogas production, food processing, genetic engineering, antibiotic production, bio-detergents, vaccine production, antibodies, and tissue culture.
• Cloning: A biotechnology process where animals are produced from a body cell without male sperm, also used to improve crop growth and quality.
• Bioengineering: Techniques like creating artificial limbs, joints, or body parts from metals or plastics, and improving crop quality.
• Nuclear Biology (Radiation Biology): Study of the effects of radioactivity on living organisms.
• Space Biology: Study of survival challenges for living things in outer space.
• Exobiology: Study of potential life elsewhere in the universe.
• Genomics: Study of an organism’s entire DNA sequence (genome).
• Bioinformatics: Management and analysis of biological data stored in databases.
• Biometrics: Verification of a person using body features like iris patterns or behavioral traits.

Study of Biology Helps us in Many Ways

• Appreciation of Nature: Biology helps us marvel at the vast variety of plants and animals while understanding their shared features.
• Keeping Healthy: Biology explains disease causes and how germs spread through insects, wind, or water, helping us take better care of our health.
• Conservation of Natural Resources: Biology highlights the interdependence of plants and animals, encouraging conservation of forests, wildlife, petroleum, coal, and metal deposits.
• Growing More Food: Biology contributes to developing new plant varieties and animal breeds, and understanding plant and animal diseases to increase food production.
• Making Us Conscious Citizens: Biology helps address issues like sanitation, public health, and water supply.
• Population Control: Biology raises awareness about the need to manage rapid population growth.
• Pollution Control: Biology helps identify and combat pollution from population growth, industries, transport, and insecticides, which harm human health.
• Careers in Biology: Knowledge of biology is essential for careers like doctor, dentist, bacteriologist, pathologist, druggist, entomologist, forester, teacher, veterinary doctor, and biotechnologist.

Points to Remember

• Biology is the study of living organisms.
• Biology has grown slowly over time but rapidly in the 20th century, with even faster growth expected in the 21st century.
• Biology includes branches like Zoology, Botany, Mycology, Cytology, Ecology, and Genetics.
• Biology is a foundation for careers in medicine, agriculture, pharmacology, and more.
• Biology helps us appreciate nature, stay healthy, grow more food, and address population and pollution issues.