Biology
🔒 Log in to trackBranches of biology and ecology
🔒 Log in to trackBranches of study (-ologies)
| Branch | Study of | Branch | Study of |
|---|---|---|---|
| Ornithology | Birds | Entomology | Insects |
| Ichthyology | Fish | Herpetology | Reptiles and amphibians |
| Mycology | Fungi | Phycology | Algae |
| Cytology | Cells | Histology | Tissues |
| Genetics | Heredity | Taxonomy | Classification |
| Palaeontology | Fossils | Anthropology | Humans / human cultures |
| Pathology | Diseases | Virology | Viruses |
| Cardiology | Heart | Nephrology | Kidneys |
| Dermatology | Skin | Haematology | Blood |
| Oncology | Cancer | Ophthalmology | Eyes |
| Osteology | Bones | Neurology | Nervous system |
| Pomology | Fruits | Olericulture | Vegetables |
| Floriculture | Flowers | Horticulture | Garden crops |
Culture / rearing
| Term | Rearing of |
|---|---|
| Apiculture | Honey bees |
| Sericulture | Silkworms (silk) |
| Pisciculture | Fish |
| Viticulture | Grapes |
| Lac culture | Lac insects |
Ecology
- 'Ecology' was coined by Ernst Haeckel; 'ecosystem' by A.G. Tansley (1935).
- A food chain runs: producers (green plants) → primary consumers (herbivores) → secondary consumers → tertiary consumers. Decomposers (bacteria, fungi) recycle nutrients.
- 10% law (Lindeman): only about 10% of energy passes to the next trophic level; the rest is lost mostly as heat. Hence food chains are short (usually 3–5 levels).
- The pyramid of energy is always upright; the pyramid of biomass in a pond can be inverted.
- Biomagnification — non-degradable chemicals like DDT and mercury increase in concentration at higher trophic levels.
- The flow of energy is one-way; nutrients cycle.
Detailed notes
Branches of study — the -ology table
| Branch | Studies |
|---|---|
| Ornithology | Birds |
| Entomology | Insects |
| Ichthyology | Fishes |
| Herpetology | Reptiles and amphibians |
| Mycology | Fungi |
| Virology | Viruses |
| Cytology | Cells |
| Histology | Tissues |
| Oncology | Cancer |
| Cardiology | Heart |
| Ophthalmology | Eye |
| Anthology | Flowers |
| Trap pair: entomology = insects (not etymology — words). Apiology = bees; malacology = molluscs. |
Culture words — rearing living things
Apiculture = honeybees (honey). Sericulture = silkworms (silk). Pisciculture = fish. Aquaculture = water organisms. Horticulture = garden plants. Floriculture = flowers. Vermiculture = earthworms. Silviculture = forest trees. Poultry farming = fowl. India's colour revolutions: Green — food grain (M.S. Swaminathan in India; Norman Borlaug worldwide), White — milk (Verghese Kurien, Operation Flood), Blue — fish, Yellow — oilseeds.
Ecosystem and the 10% law
An ecosystem = living community + its physical surroundings. Food chain: producers (green plants) → herbivores (primary consumers) → carnivores (secondary, tertiary). Lindeman's 10% law: only about 10% of energy passes to the next level — 10,000 J of producers gives 1,000 J to herbivores, 100 J to small carnivores, 10 J to big ones. Decomposers (bacteria, fungi) recycle nutrients. A food web is interlinked chains; bioaccumulation makes toxins concentrate up the chain.
Cycles, conservation, biodiversity
Nitrogen cycle: soil nitrogen → plants (via Rhizobium bacteria in legume root nodules) → animals → back to soil. Carbon cycle ties respiration, photosynthesis and fuels. Conservation firsts: Jim Corbett National Park (1936) — India's first; Project Tiger (1973); Chipko movement (1973) — villagers hugging trees. IUCN Red List ranks threatened species (extinct → vulnerable → least concern); the Red Data Book records them. Ramsar sites = wetlands.
Pollution and milestones
Air: CO, SO₂, NOₓ, particulates; BOD (biochemical oxygen demand) measures water pollution — higher BOD, dirtier water. Silent Spring (Rachel Carson, 1962) warned against pesticides like DDT. Cloning milestone: Dolly the sheep (1996), first cloned mammal. Norman Borlaug = father of the Green Revolution; Salim Ali = the birdman of India.
Quick revision
- Ornithology–birds, entomology–insects, ichthyology–fish, herpetology–reptiles, mycology–fungi, oncology–cancer.
- Apiculture–bees, sericulture–silk, pisciculture–fish, vermiculture–worms, silviculture–trees.
- 10% law (Lindeman): 10,000 → 1,000 → 100 → 10 J up the chain.
- Corbett 1936 first park; Project Tiger 1973; Chipko 1973; Dolly the sheep 1996.
- Green–Swaminathan/Borlaug, White–Kurien, Blue–fish; Rhizobium fixes nitrogen in legume nodules.
Types of questions asked
Every way this subtopic shows up in exams — how to recognise it, the formula or logic to use, and a solved example.
Type 1: Branch of study → organismvery common4 practice Q
'Ornithology is the study of…', 'entomology / ichthyology / herpetology / mycology', 'study of cancer / heart / eye', odd-one-out among -ology branches.
- Animals: ornithology–birds, entomology–insects, ichthyology–fishes, herpetology–reptiles+amphibians, apiology–bees.
- Micro/inner: mycology–fungi, virology–viruses, cytology–cells, histology–tissues.
- Medical: oncology–cancer, cardiology–heart, ophthalmology–eye, nephrology–kidney.
- Kill the trap: entomology is insects, NOT etymology (words). Why: root + animal = answer; cluster-learn five at a time.
Example: Entomology is the study of —
Insects. Don't confuse with etymology (word origins). Ichthyology is fish; ornithology, birds.
Type 2: Culture/rearing word ↔ creaturevery common3 practice Q
'Sericulture is associated with…', 'apiculture / pisciculture / vermiculture', 'which culture is for flowers', match-the-column of cultures.
- Apiculture–bees (honey); sericulture–silkworms (silk); pisciculture–fish; aquaculture–water organisms.
- Horticulture–gardens; floriculture–flowers; vermiculture–earthworms; silviculture–trees.
- Root logic helps: api- (bee), seri- (silk), pisci- (fish), vermi- (worm), silvi- (forest). Why: each word is Latin root + culture; decode the root when unsure.
Example: Sericulture is the rearing of —
Silkworms for silk production. Apiculture keeps bees, pisciculture fish.
Type 3: Food chain and the 10% law (computed)very common3 practice Q
'Producers trap 10,000 J, energy at the third level', 'the 10% law was given by…', 'which are primary consumers', 'energy flow is always…'.
- Chain: producers → primary (herbivores) → secondary → tertiary; energy flows one way, decreasing.
- Lindeman's 10% law: keep chopping a zero — 10,000 J → 1,000 J (2nd level) → 100 J (3rd) → 10 J (4th) → 1 J (5th).
- 'Third trophic level' = second consumer = small carnivores: 100 J from a 10,000 J base. Count levels, not names.
Example: Producers store 10,000 J. By the 10% law, the energy reaching the third trophic level is —
10,000 → 1,000 (herbivores) → 100 J (small carnivores). Each step keeps only a tenth.
Type 4: Conservation firsts and biodiversitycommon3 practice Q
'First national park of India', 'Project Tiger was launched in…', 'Chipko movement', 'IUCN Red List', 'which bacteria fix nitrogen in legumes'.
- Jim Corbett (1936) = first national park; Project Tiger (1973); Chipko movement (1973, tree-hugging, Sunderlal Bahuguna).
- IUCN Red List + Red Data Book = threatened species records; Ramsar = wetlands.
- Rhizobium in legume root nodules fixes atmospheric nitrogen — the natural fertiliser.
Example: India's first national park (1936) is —
Jim Corbett National Park (Uttarakhand; originally Hailey). Project Tiger began there in 1973.
Type 5: Colour revolutions and scientistscommon3 practice Q
'White Revolution is related to…', 'father of the Green Revolution', 'who is the birdman of India', 'Blue Revolution'.
- Green–food grain (M.S. Swaminathan in India; Norman Borlaug worldwide); White–milk (Verghese Kurien, Operation Flood); Blue–fish; Yellow–oilseeds.
- Salim Ali = birdman of India; Rachel Carson = Silent Spring (DDT warning); Dolly the sheep (1996) = first cloned mammal.
- Pair the colour with the produce first, then attach the name.
Example: The White Revolution (Operation Flood) in India is associated with —
Milk production, led by Verghese Kurien (Amul). Green was food grain, Blue was fish.
Type 6: Ecology basics and pollution measurescommon2 practice Q
'BOD measures…', 'which organisms are decomposers', 'ozone layer position', 'food web is…', 'bioaccumulation'.
- BOD (biochemical oxygen demand) — higher value = more polluted water.
- Decomposers = bacteria and fungi recycling nutrients; food web = many interlinked food chains.
- Pollutants like DDT bioaccumulate up the food chain — top predators get the most.
- Ozone layer sits in the stratosphere; CFCs were its destroyer (Montreal Protocol, 1987).
Example: BOD (biochemical oxygen demand) of a water sample indicates —
Its pollution level: more organic waste means bacteria consume more oxygen, so a HIGHER BOD means dirtier water.
Formulas
E₁ = energy at the producer level, n = trophic level
Shortcut tricks
⚡ Culture words by root
Api = bee (apiary), Seri = silk, Pisci = fish (Pisces), Viti = vine/grapes, Pomo = fruit (pomegranate), Olera = vegetables.
Example: Sericulture is the rearing of?
Silkworms.
⚡ Study-of roots
Ornitho = bird, Ento = insect, Ichthyo = fish, Herpeto = creeping animals, Myco = fungus, Phyco = seaweed/algae, Onco = tumour, Nephro = kidney.
Where students lose marks
Confusing entomology (insects) with etymology (word origins).
Mixing up pisciculture (fish) and pomology (fruits).
Saying energy cycles in an ecosystem — it flows one way; nutrients cycle.
Practice sets — 20 questions
Sets of 10, mixed across the question types above. Each answer comes with a step-by-step explanation.
Topic test · 10 questions
Suggested time 3 min · wrong answers go to your mistake notebook automatically.