Basic Biology

Biology: The scientific study of life and living organisms. Derived from Greek words 'bios' (life) and 'logos' (study).

Branches of Biology: Botany (study of plants), Zoology (study of animals), Microbiology (study of microorganisms), Ecology (study of organisms and environment), Genetics (study of heredity).

Importance: Understanding life processes, disease prevention, agriculture improvement, environmental conservation, biotechnology applications.

Growth: Increase in size and mass. Irreversible in living organisms. Plants grow throughout life; animals stop after maturity.

Nutrition: Process of obtaining and utilizing food. Autotrophic (plants make food) and Heterotrophic (animals consume food).

Respiration: Breakdown of food to release energy. Aerobic (with oxygen) and Anaerobic (without oxygen).

Excretion: Removal of metabolic waste products. CO₂, urea, sweat are excretory products.

Movement: Change in position or place. Animals show locomotion; plants show growth movements (tropisms).

Reproduction: Production of new individuals. Sexual (two parents) and Asexual (single parent).

Sensitivity/Irritability: Ability to respond to stimuli. Plants respond to light, gravity; animals to touch, sound, light.

Adaptation: Features that help organisms survive in their environment. Cactus has spines to reduce water loss.

Taxonomy: Science of classification. Organisms grouped based on similarities and evolutionary relationships.

Five Kingdom Classification: Monera (bacteria), Protista (unicellular eukaryotes), Fungi (decomposers), Plantae (plants), Animalia (animals).

Binomial Nomenclature: Two-name system by Carolus Linnaeus. Generic name (genus) + specific name (species). Example: Homo sapiens (humans).

Hierarchy: Kingdom → Phylum → Class → Order → Family → Genus → Species.

Importance: Systematic organization, easy identification, understanding evolutionary relationships, studying biodiversity.

Cell Theory: All living organisms are made of cells. Cell is the basic structural and functional unit of life. New cells arise from pre-existing cells.

Proposed by: Schleiden (plant cells), Schwann (animal cells), Virchow (cell division).

Types of Cells: Prokaryotic (no nucleus, bacteria) and Eukaryotic (true nucleus, plants and animals).

Unicellular vs Multicellular: Unicellular organisms have single cell (Amoeba, bacteria). Multicellular have many cells (humans, plants).

Cell Size: Microscopic (1-100 micrometers). Smallest cell: Mycoplasma. Largest cell: Ostrich egg.

Cell: Basic unit of life. Example: Nerve cell, muscle cell.

Tissue: Group of similar cells performing same function. Example: Epithelial tissue, connective tissue.

Organ: Group of different tissues working together. Example: Heart, kidney, leaf.

Organ System: Group of organs working together. Example: Digestive system, respiratory system.

Organism: Complete living being. Example: Human, mango tree.

Hierarchy: Cell → Tissue → Organ → Organ System → Organism.

Biodiversity: Variety of life forms on Earth. Includes diversity of species, genes, and ecosystems.

Importance: Ecological balance, food security, medicines, economic value, aesthetic value.

Threats: Habitat destruction, pollution, climate change, overexploitation, invasive species.

Conservation: Protection and preservation of biodiversity. In-situ (national parks, sanctuaries) and Ex-situ (zoos, botanical gardens, seed banks).

Endemic Species: Species found only in specific geographical area. Example: Lion-tailed macaque in Western Ghats.

Endangered Species: Species at risk of extinction. Example: Bengal tiger, Great Indian bustard.

Observation: Noticing phenomena in nature using senses or instruments.

Hypothesis: Tentative explanation based on observations. Must be testable.

Experimentation: Testing hypothesis through controlled experiments. Variables: independent, dependent, controlled.

Data Collection: Recording observations and measurements systematically.

Analysis: Interpreting data using statistics and graphs.

Conclusion: Accepting or rejecting hypothesis based on results.

Theory: Well-tested explanation supported by multiple experiments. Example: Cell theory, Theory of evolution.