Basic Science (Biology) Revision Notes

This comprehensive revision guide covers key concepts in Biology relevant for the Forester Exam, focusing on 12th standard basic science. It’s designed for quick and effective revision.

Table of Contents

I. The Living World

Characteristics of Living Organisms:
Growth: Irreversible increase in mass and number of cells. (Note: Non-living things can also grow, e.g., mountains, but through external accumulation of material).
Reproduction: Production of offspring (sexual/asexual). (Note: Not all living organisms reproduce, e.g., mules, sterile couples, worker bees).
Metabolism: Sum total of all chemical reactions occurring in a living organism (anabolism + catabolism). It is a defining feature of life.
Cellular Organization: All living organisms are composed of one or more cells. This is a defining feature.
Consciousness: Ability to sense environment and respond to stimuli. It is the most defining feature of living organisms. (Self-consciousness is unique to humans).
Movement: Internal (cytoplasmic streaming) or external (locomotion).
Adaptation: Ability to adjust to the environment.
Homeostasis: Maintenance of a stable internal environment.

Biodiversity: The variety of life forms on Earth.
Nomenclature:

Binomial Nomenclature (Linnaeus): Each organism has two parts in its scientific name – Genus (capitalized) and species (lowercase), both italicized when typed, underlined separately when handwritten. E.g., Mangifera indica* (Mango).

Universal Rules: Latin origin, italics, first letter of genus capital, specific epithet lowercase, author’s name in abbreviated form after species (e.g., Mangifera indica* Linn.).

Taxonomy & Systematics:
Taxonomy: Science of identifying, classifying, and naming organisms.
Systematics: Study of evolutionary relationships among organisms.
Taxonomic Categories (Hierarchy): King Philip Came Over For Good Soup (Kingdom, Phylum/Division, Class, Order, Family, Genus, Species).
Species: Group of individuals that can interbreed and produce fertile offspring. (Biological species concept).
Taxonomic Aids: Herbarium, Botanical Gardens, Museums, Zoological Parks, Keys (analytical, based on contrasting characters), Flora, Manuals, Monographs, Catalogues.

II. Biological Classification

Kingdom Monera:
Organisms: Bacteria (prokaryotes).
Cell Type: Prokaryotic, unicellular.
Cell Wall: Peptidoglycan (not cellulose).
Nutrition: Autotrophic (photosynthetic, chemosynthetic) or Heterotrophic (saprophytic, parasitic).
Reproduction: Asexual (binary fission), sexual (conjugation – primitive DNA transfer).

Examples: Bacillus, Lactobacillus, Nostoc, Anabaena* (Cyanobacteria/Blue-green algae).

Kingdom Protista:
Organisms: Unicellular eukaryotes.
Cell Type: Eukaryotic, unicellular.
Cell Wall: Present in some (e.g., diatoms), absent in others.
Nutrition: Auto (photosynthetic) or Heterotrophic (holozoic, saprophytic).
Reproduction: Asexual (binary fission), sexual (fusion of gametes).
Examples: Diatoms, Dinoflagellates, Euglenoids, Slime Moulds, Protozoans (Amoeboid, Flagellated, Ciliated, Sporozoans).

Kingdom Fungi:
Organisms: Heterotrophic eukaryotes.
Cell Type: Eukaryotic, mostly multicellular (except yeast which is unicellular).
Cell Wall: Chitin and polysaccharides.
Nutrition: Heterotrophic (saprophytic, parasitic, symbiotic).
Body Structure: Filaments called hyphae, forming a mycelium.
Reproduction: Asexual (spores: conidia, sporangiospores, zoospores), sexual (oospore, ascospore, basidiospore).

Examples: Yeast (Saccharomyces), Penicillium, Agaricus (mushroom), Puccinia* (rust).

Economic Importance: Antibiotics, spoilage, decomposers.

Kingdom Plantae:
Organisms: Multicellular eukaryotes.
Cell Type: Eukaryotic, multicellular.
Cell Wall: Cellulose.
Nutrition: Autotrophic (photosynthesis).
Life Cycle: Alternation of generations (sporophyte and gametophyte).
Groups: Algae, Bryophytes, Pteridophytes, Gymnosperms, Angiosperms.

Kingdom Animalia:
Organisms: Multicellular eukaryotes.
Cell Type: Eukaryotic, multicellular.
Cell Wall: Absent.
Nutrition: Heterotrophic (holozoic).
Mode of life: Motile (except sponges).
Reproduction: Sexual reproduction is primary.
Body Plans: Asymmetry, Radial Symmetry, Bilateral Symmetry.

Viruses, Viroids, Prions, Lichens:
Viruses: Non-cellular, infectious agents. Obligate intracellular parasites. Genetic material (DNA or RNA) enclosed in a protein coat (capsid).
Viroids: Smaller than viruses, circular RNA, no protein coat. Cause plant diseases.
Prions: Abnormally folded proteins, cause neurological diseases (e.g., Mad Cow Disease).
Lichens: Symbiotic association between algae (autotrophic phycobiont) and fungi (heterotrophic mycobiont). Pioneer species, pollution indicators.

III. Cell: The Unit of Life

Cell Theory (Schleiden & Schwann):
All living organisms are composed of cells and cell products.
The cell is the structural and functional unit of life.

(Rudolf Virchow added: Omnis cellula e cellula* – all cells arise from pre-existing cells).

Prokaryotic Cells (e.g., Bacteria):
Lack a true nucleus.
Genetic material (nucleoid) is naked, circular DNA.
Absence of membrane-bound organelles.
Ribosomes are 70S type.
Cell wall present (peptidoglycan).
Have a capsule (glycocalyx) in some.
Pili, fimbriae for attachment. Flagella for motility.
Mesosomes: Infoldings of cell membrane, involved in respiration, DNA replication, cell wall formation.

Eukaryotic Cells (Plants, Animals, Fungi, Protists):
Possess a true nucleus (genetic material enclosed by nuclear envelope).
Presence of membrane-bound organelles.
Ribosomes are 80S type (cytoplasm) and 70S type (mitochondria, chloroplasts).
Cell Membrane (Plasma Membrane): Fluid Mosaic Model (Singer & Nicolson) – dynamic, selectively permeable. Composed of lipids (phospholipid bilayer), proteins, and carbohydrates.
Cell Wall (Plants & Fungi): Rigid outer layer, provides support and protection. (Cellulose in plants, chitin in fungi).
Cytoplasm: Jelly-like substance filling the cell, site of many metabolic reactions.
Endoplasmic Reticulum (ER): Network of tubules and sacs.
Rough ER (RER): Has ribosomes, involved in protein synthesis and secretion.
Smooth ER (SER): Lacks ribosomes, involved in lipid synthesis, steroid hormone synthesis, detoxification.
Golgi Apparatus: Stacks of flattened sacs (cisternae). Modifies, sorts, and packages proteins and lipids. Forms lysosomes.
Lysosomes: “Suicidal bags,” contain hydrolytic enzymes (acid hydrolases) for digestion of cellular waste and foreign particles.
Vacuoles: Membrane-bound sacs.
Plant cells: Large central vacuole, maintains turgor, stores water, nutrients, waste.
Animal cells: Smaller, temporary vacuoles.
Mitochondria: “Powerhouse of the cell.” Double-membrane structure. Inner membrane folded into cristae. Site of cellular respiration and ATP production. Have their own 70S ribosomes and circular DNA.
Chloroplasts (Plant cells & Algae): Site of photosynthesis. Double-membrane structure. Contains chlorophyll within thylakoids stacked into grana. Have their own 70S ribosomes and circular DNA.
Ribosomes: Protein synthesis factories. 70S (prokaryotes, mitochondria, chloroplasts), 80S (eukaryotic cytoplasm).
Cytoskeleton: Network of protein filaments (microtubules, microfilaments, intermediate filaments). Provides structural support, cell motility, intracellular transport.
Cilia & Flagella: Hair-like or whip-like appendages for locomotion or moving substances. (9+2 microtubule arrangement).
Centrosome & Centrioles (Animal cells): Involved in cell division, formation of basal bodies for cilia and flagella. (9+0 microtubule arrangement in centrioles).
Nucleus: Contains genetic material (DNA) organized into chromosomes. Nuclear envelope (double membrane), nuclear pores, nucleoplasm, nucleolus (rRNA synthesis).

Cell Cycle and Cell Division:
Cell Cycle: Ordered sequence of events that involve cell growth and cell division.
Interphase: G1 (gap 1 – cell growth), S (synthesis – DNA replication), G2 (gap 2 – cell growth, preparation for mitosis).
M-phase (Mitosis/Meiosis): Actual cell division.
Mitosis (Somatic cells): “Equational division” – produces two identical daughter cells with the same number of chromosomes as the parent cell (2n -> 2n).
Phases: Prophase, Metaphase, Anaphase, Telophase. Followed by cytokinesis (cytoplasm division).
Meiosis (Germ cells): “Reductional division” – produces four haploid (n) daughter cells from a diploid (2n) parent cell, involving two successive divisions (Meiosis I and Meiosis II).
Key events: Crossing over (Meiosis I, Prophase I – Pachytene) leading to genetic recombination, reduction of chromosome number. Essential for sexual reproduction.

Mnemonic for Mitosis Phases: Please Make A Toast (Prophase, Metaphase, Anaphase, Telophase)

IV. Plant Physiology

Photosynthesis: Process by which green plants synthesize organic food (glucose) from inorganic substances (CO2 and H2O) using light energy and chlorophyll.
Equation: 6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2
Site: Chloroplasts.
Two stages:
Light-dependent reactions: Occur in thylakoid membranes. Light energy converted to chemical energy (ATP and NADPH). Water splits (photolysis) releasing O2.
Light-independent reactions (Calvin Cycle / C3 cycle): Occur in stroma. ATP and NADPH used to fix CO2 into glucose.
Factors affecting photosynthesis: Light intensity, CO2 concentration, temperature, water availability.
C3 vs C4 Plants:
C3 plants: First stable product is a 3-carbon compound (PGA). Found in temperate regions. (E.g., Wheat, Rice).
C4 plants: First stable product is a 4-carbon compound (OAA). Have Kranz anatomy. Efficient at high temperatures and high light intensities. Minimize photorespiration. (E.g., Maize, Sugarcane).

Respiration (Cellular Respiration): Breakdown of organic food molecules (glucose) to release energy (ATP).
Aerobic Respiration: Requires oxygen. Occurs in cytoplasm (glycolysis) and mitochondria (Krebs cycle, electron transport system). Releases large amount of energy (~38 ATP).
Anaerobic Respiration: Without oxygen. Occurs in cytoplasm. Releases less energy (~2 ATP).
Alcoholic Fermentation: Glucose → Ethanol + CO2 (e.g., Yeast).
Lactic Acid Fermentation: Glucose → Lactic Acid (e.g., Muscle cells during strenuous exercise).

Plant Growth and Development:
Growth: Irreversible increase in size, mass, or number.
Development: Sum of growth and differentiation.
Plant Growth Regulators (Phytohormones):
Auxins: Cell elongation, apical dominance, root initiation, fruit development. (e.g., IAA)
Gibberellins: Stem elongation, seed germination, bolting. (e.g., GA3)
Cytokinins: Cell division, lateral bud growth, delay senescence.
Ethylene: Fruit ripening, senescence, abscission. (Gaseous hormone).
Abscisic Acid (ABA): Stress hormone, dormancy, abscission, stomatal closure.

Mineral Nutrition: Plants require macro (C, H, O, N, P, K, Ca, Mg, S) and micro-nutrients (Fe, Mn, Cu, Zn, B, Mo, Cl, Ni).

Transport in Plants:
Xylem: Transports water and minerals from roots to leaves (unidirectional).
Phloem: Transports prepared food (sugars) from leaves to all parts of the plant (bidirectional).
Transpiration: Loss of water vapor from aerial parts of the plant, mainly through stomata. Creates a ‘transpirational pull’ for water absorption.

V. Human Physiology

Digestive System:
Organs: Mouth, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (caecum, colon, rectum, anus).
Accessory Glands: Salivary glands, liver (produces bile), pancreas (produces digestive enzymes and hormones).
Digestion:
Carbohydrates: Start in mouth (salivary amylase), completed in small intestine (pancreatic amylase, disaccharidases).
Proteins: Start in stomach (pepsin), completed in small intestine (trypsin, chymotrypsin, peptidases).
Fats: Digested in small intestine (lipases, with help of bile emulsification).
Absorption: Primarily occurs in small intestine (villi and microvilli increase surface area).

Respiratory System:
Organs: Nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs (alveoli).
Mechanism of Breathing:
Inhalation: Diaphragm contracts and moves down, external intercostal muscles contract, ribs move up and out, thoracic volume increases, pressure decreases, air rushes in.
Exhalation: Diaphragm relaxes, internal intercostal muscles contract (for forced exhalation), thoracic volume decreases, pressure increases, air forced out.
Gas Exchange: Occurs in alveoli by diffusion. O2 into blood, CO2 out of blood.
Transport of Gases:
Oxygen: Primarily bound to hemoglobin (oxyhemoglobin) in RBCs.
Carbon Dioxide: Mostly as bicarbonate ions (~70%), some with hemoglobin (carbaminohemoglobin) and dissolved in plasma.

Circulatory System (Blood Vascular System):
Heart: Four-chambered organ, pumps blood. Right side (deoxygenated blood), left side (oxygenated blood).
Blood Vessels: Arteries (carry blood away from heart), Veins (carry blood towards heart), Capillaries (site of exchange).
Blood: Fluid connective tissue.
Plasma: Liquid matrix (~55%).
Formed Elements (~45%):
RBCs (Erythrocytes): Biconcave, anucleated, contain hemoglobin, transport O2.
WBCs (Leukocytes): Immune function. (Granulocytes: Neutrophils, Eosinophils, Basophils; Agranulocytes: Lymphocytes, Monocytes).
Platelets (Thrombocytes): Blood clotting.
Blood Groups (ABO system): Based on antigens (A, B) on RBC surface. Antibodies (a, b) in plasma.
Universal Donor: O-group (no A/B antigens).
Universal Recipient: AB+ group (has both A/B antigens, no anti-A/anti-B antibodies).
Rh Factor: Another antigen. Rh+ (present), Rh- (absent).

Excretory System:
Organs: Kidneys (filter blood, form urine), Ureters, Urinary Bladder, Urethra.
Kidney Structure: Renal cortex, renal medulla (renal pyramids), renal pelvis.
Nephron: Functional unit of the kidney. Composed of Glomerulus (filters blood), Bowman’s capsule, Renal tubule (PCT, Loop of Henle, DCT, Collecting Duct).
Urine Formation:
Glomerular Filtration: Blood filtered from glomerulus into Bowman’s capsule.
Tubular Reabsorption: Essential substances (water, glucose, amino acids, salts) reabsorbed back into blood.
Tubular Secretion: Waste products (H+, K+, creatinine, drugs) secreted from blood into tubular filtrate.
Regulation: ADH (Antidiuretic Hormone) or Vasopressin increases water reabsorption. Renin-Angiotensin-Aldosterone System (RAAS) regulates blood pressure and fluid balance.

Nervous System:
Central Nervous System (CNS): Brain and Spinal Cord.
Peripheral Nervous System (PNS): Nerves extending from CNS.
Somatic Nervous System: Controls voluntary movements.
Autonomic Nervous System (ANS): Controls involuntary functions.
Sympathetic: “Fight or flight” response.
Parasympathetic: “Rest and digest” response.
Neuron: Structural and functional unit of the nervous system. Dendrites (receive signals), Cell body (soma), Axon (transmits signals), Synaptic knob (releases neurotransmitters).
Nerve Impulse: Electrical and chemical signal transmission.

Endocrine System:
Glands: Ductless glands that secrete hormones directly into the bloodstream.
Hormones: Chemical messengers that regulate various body functions.
Key Glands and Hormones:
Hypothalamus: Releasing & Inhibiting hormones (regulates pituitary).
Pituitary (Master Gland): Growth Hormone (GH), TSH, ACTH, FSH, LH, Prolactin, ADH, Oxytocin.
Thyroid: Thyroxine (T4), Triiodothyronine (T3) – regulate metabolism. Calcitonin – lowers blood calcium.
Parathyroid: Parathyroid Hormone (PTH) – raises blood calcium.
Adrenal: Cortex (Cortisol, Aldosterone), Medulla (Adrenaline/Epinephrine, Noradrenaline/Norepinephrine – “stress hormones”).
Pancreas: Insulin (lowers blood glucose), Glucagon (raises blood glucose).
Gonads (Testes/Ovaries): Testosterone (males), Estrogen, Progesterone (females) – regulate reproduction and secondary sexual characteristics.
Thymus: Thymosins – immune development.
Pineal: Melatonin – regulates sleep-wake cycle.

Reproductive System:
Male: Testes (sperm and testosterone production), Epididymis, Vas Deferens, Seminal Vesicles, Prostate Gland, Urethra, Penis.
Female: Ovaries (ova and estrogen/progesterone production), Fallopian Tubes (site of fertilization), Uterus (site of fetal development), Cervix, Vagina.
Gametes: Sperm (male), Ovum (female).
Fertilization: Fusion of sperm and ovum, usually in fallopian tube.
Gestation: Pregnancy period.

VI. Genetics and Evolution

Mendel’s Laws of Inheritance:
Law of Dominance: In a heterozygote, one allele (dominant) masks the expression of the other (recessive).
Law of Segregation: Alleles for each gene separate during gamete formation, so each gamete receives only one allele.
Law of Independent Assortment: Alleles of different genes assort independently of each other during gamete formation (applies to genes on different chromosomes or far apart on the same chromosome).

Beyond Mendelian Genetics:
Incomplete Dominance: Heterozygote phenotype is intermediate between homozygous dominant and recessive (e.g., pink flower in snapdragon).
Co-dominance: Both alleles express themselves fully in the heterozygote (e.g., ABO blood groups – AB type).
Multiple Alleles: More than two alleles for a single gene (e.g., ABO blood groups, which have I^A, I^B, i alleles).
Polygenic Inheritance: Trait controlled by multiple genes, showing continuous variation (e.g., human skin color, height).
Pleiotropy: A single gene affects multiple phenotypic traits (e.g., Phenylketonuria).
Sex Determination: Chromosomal basis for determining sex (e.g., XX-XY in humans, ZZ-ZW in birds).
Sex-linked Inheritance: Genes located on sex chromosomes (e.g., hemophilia, color blindness – X-linked recessive).

DNA (Deoxyribonucleic Acid):
Structure (Watson & Crick model): Double helix, two polynucleotide strands coiled around each other.
Components: Deoxyribose sugar, phosphate group, nitrogenous bases (Adenine-Thymine, Guanine-Cytosine). A-T (2 H-bonds), G-C (3 H-bonds).
Function: Genetic material, stores and transmits hereditary information.
Replication: Semi-conservative (Meselson & Stahl experiment).

RNA (Ribonucleic Acid):
Structure: Single-stranded, ribose sugar, bases (A, U, G, C) – Uracil replaces Thymine.
Types:
mRNA (messenger RNA): Carries genetic code from DNA to ribosomes.
tRNA (transfer RNA): Carries specific amino acids to ribosomes during protein synthesis.
rRNA (ribosomal RNA): Structural and catalytic component of ribosomes.

Central Dogma of Molecular Biology (Crick): DNA → RNA → Protein.
Transcription: DNA to mRNA (in nucleus).
Translation: mRNA to protein (on ribosomes in cytoplasm).
Genetic Code: Triplet code, unambiguous, degenerate, universal.

Gene Expression Regulation: Switching genes on and off (e.g., Lac Operon in bacteria).

Evolution: Change in heritable characteristics of biological populations over successive generations.
Theories:
Lamarckism: Inheritance of acquired characters (disproved).
Darwinism (Natural Selection): Organisms with advantageous traits survive and reproduce more, passing on those traits. “Survival of the fittest.”
Modern Synthesis of Evolution: Integrates Darwinian natural selection with Mendelian genetics (gene mutations, genetic drift, gene flow).
Evidence for Evolution: Homologous and analogous organs, embryonic development, fossils, molecular biology (DNA similarities).
Speciation: Formation of new species.

VII. Biology and Human Welfare

Human Health and Disease:
Pathogens: Disease-causing microorganisms (bacteria, viruses, fungi, protozoans, worms).
Common Diseases:

Bacterial: Typhoid (Salmonella typhi), Pneumonia (Streptococcus pneumoniae*), Cholera, TB.

Viral: Common cold (Rhinovirus), Measles, Polio, AIDS (HIV), Dengue, Chikungunya, Covid-19.

Protozoan: Malaria (Plasmodium), Amoebiasis (Entamoeba histolytica), Kala-azar (Leishmania*).

Fungal: Ringworm.
Helminthic: Ascaris, Filariasis.
Immunity: Body’s ability to fight off infections.
Innate Immunity: Non-specific, present from birth (skin, mucous membranes, phagocytes).
Acquired Immunity: Specific, develops after exposure to pathogen.
Active: Body produces its own antibodies (vaccination, natural infection).
Passive: Antibodies transferred from outside (mother to fetus, anti-venom).
AIDS (Acquired ImmunoDeficiency Syndrome): Caused by HIV, attacks T-lymphocytes, compromising immune system.
Cancer: Uncontrolled growth of cells.
Drug Abuse: Addiction to substances affecting nervous system.

Microbes in Human Welfare:
Household Products: Lactic Acid Bacteria (LAB) in curd, Yeast in bread/fermentation.

Industrial Products: Alcoholic beverages (Yeast), Antibiotics (Penicillium*), Organic acids.

Sewage Treatment (Wastewater Treatment Plants – WWTPs): Primary (physical), Secondary (biological using microbes), Tertiary (chemical/advanced).
Biogas Production: Anaerobic bacteria ferment organic waste to produce biogas (mostly methane).

Biofertilizers: Microbes that enrich soil fertility (e.g., Rhizobium* in legumes, nitrogen-fixing cyanobacteria).

Biocontrol Agents: Using microbes/insects to control pests (e.g., Bacillus thuringiensis* – Bt cotton).

Biotechnology Principles and Processes:
Genetic Engineering: Manipulation of genetic material to alter the characteristics of an organism.
Recombinant DNA Technology: Combining DNA from two different sources.
Tools: Restriction enzymes (“molecular scissors”), Cloning vectors (plasmids), DNA ligase (“molecular glue”).
Steps: Isolation of DNA, fragmentation, cloning, ligation, insertion into host, gene transfer, expression.
Applications:
Medical: Insulin production (Humulin), Gene therapy, Molecular diagnosis (ELISA, PCR).
Agricultural: Bt crops (pest resistance), Golden Rice (Vitamin A enriched).

VIII. Ecology and Environment

Organisms and Populations:
Ecology: Study of interactions among organisms and their environment.
Levels: Organism, Population, Community, Ecosystem, Biome, Biosphere.
Population Interactions:
Mutualism (+/+): Both benefit (e.g., lichens, mycorrhizae).
Commensalism (+/0): One benefits, other unaffected (e.g., orchids on mango tree).
Competition (-/-): Both harmed.
Predation (+/-): Predator benefits, prey harmed.
Parasitism (+/-): Parasite benefits, host harmed.
Amensalism (-/0): One harmed, other unaffected.

Ecosystem: Functional unit of nature where living organisms interact with each other and their physical environment.
Components: Abiotic (physical factors) and Biotic (producers, consumers, decomposers).
Energy Flow: Unidirectional. Producers → Primary Consumers → Secondary Consumers → Tertiary Consumers.
10% Law (Lindeman): Only 10% of energy is transferred from one trophic level to the next.
Food Chain & Food Web: Interconnected feeding relationships.
Ecological Pyramids: Pyramid of numbers, biomass, energy. (Pyramid of energy is always upright).
Nutrient Cycling (Biogeochemical Cycles): Carbon cycle, Nitrogen cycle, Phosphorus cycle.

Biodiversity and Conservation:
Biodiversity Hotspots: Regions with high species richness and endemism, under threat.
Threats to Biodiversity: Habitat loss and fragmentation, over-exploitation, alien species invasions, co-extinctions (HIPPO – Habitat destruction, Invasion, Pollution, Population, Overharvesting).
Conservation Strategies:
In-situ Conservation: Protecting species in their natural habitats (National Parks, Wildlife Sanctuaries, Biosphere Reserves, Sacred Groves).
Ex-situ Conservation: Protecting species outside their natural habitats (Botanical Gardens, Zoological Parks, Seed Banks, Gene Banks, Cryopreservation).
Endemic species: Found only in a particular geographical area.
Endangered species: At high risk of extinction.
Red Data Book (IUCN): Catalogues endangered and extinct species.

Environmental Issues:
Pollution: Undesirable changes in physical, chemical, or biological characteristics of air, water, soil.
Air Pollution: Particulates, SO2, NOx, CO, Ozone. Acid Rain, Smog.
Water Pollution: Domestic sewage, industrial effluents, pesticides, heavy metals. Eutrophication, Biomagnification.
Soil Pollution: Pesticides, industrial waste, solid waste.
Noise Pollution: High sound levels harmful to human health.
Greenhouse Effect and Global Warming: Trapping of heat by greenhouse gases (CO2, CH4, N2O, CFCs) leading to increase in Earth’s temperature.
Ozone Depletion: Depletion of stratospheric ozone layer by CFCs, leading to increased UV radiation reaching Earth. Protects from harmful UV rays.
Deforestation: Cutting down forests.
Solid Waste Management: Proper disposal and treatment of waste.
Radioactive Waste: Safe disposal for long periods.

Key Highlight: The Forester Exam often focuses on practical aspects of biology related to environment, conservation, and plant/animal life cycles. Pay special attention to these sections.

All the best for your examination!

Editorial Team

Founder & Content Creator at EduFrugal

Email View Articles