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State Board · Class 12 · Biology

Lesson 5: Origin and Evolution of Life

7 concepts · 56 practice questions with answers · Free to read

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Origin of life

Link to Std 9–10

Std 10 introduced Lamarck and Darwin; here we study the origin of life, evidences, mechanisms of evolution and human evolution in depth.

From daily life

Ingredients combine into a dish; likewise chemicals are believed to have combined into life.

Simple definition

Chemical evolution = gradual origin of life from non-living chemicals. Protobionts = molecular aggregates with some properties of life.

Origin of lifeOrigin of lifeCH₄ NH₃ H₂ H₂OSimple organicProtobiontsRNA → DNA → cellSpecial creation, cosmozoa, abiogenesis (refuted by Redi, Pasteur)Biogenesis: life from life; cannot explain the first lifeOparin (1924) + Haldane (1929): chemical evolutionBig Bang (Lemaitre 1931); Earth ~4.6 billion y; reducing atmosphere‘Hot dilute soup’: amino acids, sugars, purines, pyrimidinesProtobionts: coacervates (Oparin), microspheres (Fox)Miller–Urey (1953): CH₄:NH₃:H₂ = 1:2:2 + spark → amino acidsRNA World: first life on RNA (Woese, Crick, Orgel 1960); ribozymesFirst life ~2000 million y ago; chemoheterotroph

In the figure : Steps in the origin of life.

Rule 1 : Older theories — Special creation: created by God (a religious belief; no proof). Cosmozoa / panspermia: life came from other planets as spores; does not explain origin on Earth. Spontaneous generation (abiogenesis): life from non-living matter; refuted by Redi (flies and maggots) and Louis Pasteur (swan-neck flask). Biogenesis: life arises only from life; explains continuity but not the first life.

  • Easy : Pasteur: swan-neck flask.
  • Medium : Biogenesis = life → life.
  • Exam-type (CET) : Abiogenesis was refuted.

Rule 2 : Chemical evolution, Miller–Urey, RNA World — Oparin (1924) + Haldane (1929). Big Bang (Lemaitre 1931): universe ~20 billion y ago; Earth ~4.6 billion y ago; primitive atmosphere reducing (no oxygen; CH₄, NH₃, H₂, water). Reactions gave simple organic molecules (sugars, amino acids, purines, pyrimidines) → collected in water = ‘hot dilute soup’; polymerisation → proteins, nucleic acids → protobionts: coacervates (Oparin), microspheres (Fox). Miller and Urey (1953): CH₄:NH₃:H₂ = 1:2:2 + water vapour + electric spark → amino acids, urea, lactic acid. RNA World: first life based on RNA (Woese, Crick, Orgel 1960; ribozymes and RNA catalysis in ribosomes as evidence); DNA and proteins came later. First life ~2000 million y ago.

  • Easy : Miller: 1953.
  • Medium : Reducing = no O₂.
  • Exam-type (CET) : Coacervate = Oparin; microsphere = Fox.
Remember

O-H-M: Oparin-Haldane, Miller-Urey, … RNA first.

Common mistake and CET trap

‘Free O₂ was present’ is wrong. Trap: ‘Miller did Pasteur's experiment’ is wrong.

Shortcut

Memory clue : "Miller–Urey gases 1:2:2 = methane : ammonia : hydrogen".

Spot the difference

ScientistContribution
Redi / PasteurRefuted abiogenesis
Oparin–HaldaneChemical evolution
Miller–UreyAmino acids formed
Woese–Crick–OrgelRNA World

Practice questions

Easy
  1. 1Who refuted abiogenesis?
  2. 2What is biogenesis?
  3. 3Age of Earth?
Medium
  1. 4Primitive atmosphere?
  2. 5Haldane's ‘soup’?
  3. 6Who named coacervates?
Challenging
  1. 7Gases in Miller's experiment?
  2. 8Who proposed RNA World?
Show answers (try them yourself first)
  1. 1Pasteur.
  2. 2Life from life.
  3. 3~4.6 billion years.
  4. 4Reducing.
  5. 5Hot dilute soup.
  6. 6Oparin.
  7. 7CH₄, NH₃, H₂ (1:2:2).
  8. 8Woese, Crick, Orgel.

Early theories of evolution

From daily life

Why is the giraffe's neck long? Different explanations gave rise to several theories.

Simple definition

Organic evolution = slow, gradual, continuous and irreversible change from simple ancestors to present complex forms. Darwin: ‘descent with modification’.

Theories of evolutionTheories of evolutionLamarck 1809Darwin 1859de Vries 1901Use and disuseNatural selectionMutation theoryLamarck: acquired traits inherited (giraffe); Weismann cut tails for 21 generationsWeismann: continuity of germplasm; somatic changes not inheritedDarwin: voyage 1831–36 (Beagle), Galápagos; Wallace, Malthus5 points: overproduction, struggle, variations, natural selection, speciationSpencer: ‘survival of the fittest’; salmon ~2.8 million eggsDarwin's limits: no cause/inheritance of variations explainedde Vries: Oenothera lamarckiana; mutations = sudden, large, heritableObjections: big changes = chromosomal aberrations; rate low

In the figure : Lamarck, Darwin and de Vries.

Rule 1 : Lamarck and Darwin — Lamarck (1809): acquired traits from use/disuse and need are inherited (e.g. giraffe's neck lengthened to reach tall trees). Weismann cut rats' tails for 21 generations — no change; so germplasm continuity (somatic changes are not inherited). Darwin (voyage 1831–36; Galápagos finches and tortoises; Wallace, Malthus, artificial selection): 1 overproduction, 2 struggle for existence, 3 variations, 4 natural selection (Spencer: ‘survival of the fittest’), 5 origin of new species. Limits: cause and inheritance of variations unexplained; intermediate forms not found.

  • Easy : Lamarck: use and disuse.
  • Medium : Weismann: 21 generations.
  • Exam-type (CET) : Darwin: 5 points.

Rule 2 : de Vries' mutation theory — Hugo de Vries (1901): in 7 generations of Oenothera lamarckiana some offspring showed sudden, clear differences. Features: mutations are large, sudden, random, discontinuous; inheritable; raw material of evolution; useful ones are selected, harmful ones eliminated; accumulation gives new species. Objections: de Vries' big changes were really chromosomal aberrations; gene mutations are usually small; rate is low.

  • Easy : Mutation = sudden and inherited.
  • Medium : 1901: de Vries.
  • Exam-type (CET) : Oenothera = experimental plant.
Remember

L-D-V: Lamarck-use, Darwin-selection, de Vries-mutation.

Common mistake and CET trap

‘Darwin accepted acquired traits’ is wrong (Lamarck). Trap: ‘Weismann supported Lamarck’ is wrong (he refuted it).

Shortcut

Memory clue : "Lamarck = long neck by use; Darwin = the fit survive".

Spot the difference

TheoryMain idea
LamarckUse–disuse, acquired traits
DarwinNatural selection
de VriesMutations
WeismannGermplasm continuity

Practice questions

Easy
  1. 1Year of Lamarck's theory?
  2. 2Weismann's experiment?
  3. 3Who coined ‘survival of the fittest’?
Medium
  1. 4Island group visited by Darwin?
  2. 5First postulate of Darwin?
  3. 6Plant of de Vries?
Challenging
  1. 7Year of mutation theory?
  2. 8One objection to mutation theory?
Show answers (try them yourself first)
  1. 11809.
  2. 2Cut tails for 21 generations.
  3. 3Herbert Spencer.
  4. 4Galápagos.
  5. 5Overproduction.
  6. 6Oenothera lamarckiana.
  7. 71901.
  8. 8Changes were chromosomal aberrations.

Mechanisms of evolution, isolation and speciation

From daily life

A river dividing a village slowly makes the two sides speak differently — likewise in animals.

Simple definition

Speciation = formation of new species. A species = organisms that interbreed and produce fertile offspring.

Mechanisms and speciationMechanisms of evolution and speciationMutationRecombinationGene flowGenetic driftGene flow (migration): alleles move; populations convergeGenetic drift: chance change in allele frequency; small groups; founder effectIsolation: geographical/reproductive → gene flow stopsAllopatric: geographical barrier (Galápagos finches, marsupials)Sympatric: no barrier; reproductive isolation (cichlids, Lake Victoria)Interspecific: hybridisation + chromosome doubling (Triticum aestivum)Species = interbreed + fertile young; Mendelian population; gene poolMule (donkey × mare) is sterileEvolution = ‘descent with modification’ (Darwin)

In the figure : Mechanisms of evolution.

Rule 1 : Factors changing the gene pool — A Mendelian population = a small interbreeding group; the sum of its genes = gene pool. Changing factors: mutation, genetic recombination, gene flow (migration) (exchange of alleles), genetic drift (chance change in allele frequency; strong in small groups; founder effect: when a few individuals found a new colony), natural selection, non-random mating. Isolation = splitting a population into sub-units; barriers (river, mountains) stop gene flow.

  • Easy : Drift = chance.
  • Medium : Gene flow = migration.
  • Exam-type (CET) : Founder effect = small colony.

Rule 2 : Types of speciation — Intraspecific: (i) Allopatric — by a geographical barrier (glaciers, mountains, migration); e.g. Galápagos finches (14 species), Australian marsupials; adaptive radiation. (ii) Sympatric — without barrier, through reproductive isolation; e.g. Cichlid fishes of Lake Victoria; mutations help. Interspecific: hybridisation + chromosome doubling gives a new species — e.g. wheat Triticum aestivum (hexaploid). Sterile hybrid: mule (donkey × mare).

  • Easy : Allopatric = barrier.
  • Medium : Sympatric = no barrier.
  • Exam-type (CET) : Mule = sterile.
Remember

Allo = away (different place); sym = same place.

Common mistake and CET trap

‘Sympatric needs a geographical barrier’ is wrong. Trap: ‘genetic drift = natural selection’ is wrong.

Shortcut

Memory clue : "Allopatric = away, sympatric = same place".

Spot the difference

TypeBarrierExample
AllopatricGeographicalGalápagos finches
SympatricNoneCichlids
InterspecificHybridisationTriticum aestivum

Practice questions

Easy
  1. 1What is a gene pool?
  2. 2What is gene flow?
  3. 3What is genetic drift?
Medium
  1. 4Founder effect?
  2. 5Allopatric example?
  3. 6Sympatric example?
Challenging
  1. 7Define species.
  2. 8A sterile hybrid?
Show answers (try them yourself first)
  1. 1Sum of all genes in the population.
  2. 2Exchange of alleles by migration.
  3. 3Chance change in allele frequency.
  4. 4Drift due to a small founding group.
  5. 5Galápagos finches.
  6. 6Lake Victoria cichlids.
  7. 7Interbreed with fertile offspring.
  8. 8Mule.

Natural selection, Hardy–Weinberg and adaptive radiation

From daily life

When soot darkened tree bark, dark moths hid better and became more numerous.

Simple definition

Natural selection = those with favourable variations survive. Hardy–Weinberg = allele frequencies stay constant in a non-evolving population. Adaptive radiation = many forms from one ancestor.

Natural selectionNatural selection, Hardy–WeinbergStabilisingDirectionalDisruptiveStabilising: mean kept, extremes lost; directional: shift to one extreme (DDT, peppered moth)Disruptive: both extremes kept (seed-cracker finches)Hardy–Weinberg: p + q = 1; p² + 2pq + q² = 1Constant if no mutation, drift, gene flow, selection or non-random matingAdaptive radiation: one ancestor → many formsDarwin's finches (Galápagos): beak types; marsupials (Australia)Industrial melanism: dark moths rise in polluted areasDDT-resistant mosquitoes; antibiotic resistance (examples)

In the figure : Types of selection and Hardy–Weinberg.

Live figure

Natural selection, Hardy–Weinberg and adaptive radiation

In the app you can move this figure with your finger.

Open in the app

Rule 1 : Three types of natural selection — Stabilising: intermediate form survives, both extremes lost; variation reduced; stability (e.g. medium-weight babies). Directional: shifts towards one extreme; evolutionary change (e.g. industrial melanism — dark moths; DDT-resistant mosquitoes). Disruptive: both extremes survive, intermediate lost; two peaks; rare (e.g. African seed-cracker finches: large and small beaks).

  • Easy : Stabilising = middle.
  • Medium : Directional = one extreme.
  • Exam-type (CET) : Disruptive = both extremes.

Rule 2 : Hardy–Weinberg and adaptive radiation — Hardy–Weinberg principle: at equilibrium allele and genotype frequencies remain constant across generations. p = dominant allele, q = recessive; p + q = 1; p² + 2pq + q² = 1 (AA : Aa : aa). E.g. if q = 0.3 then p = 0.7; AA = 0.49, Aa = 0.42, aa = 0.09. Factors disturbing it: mutation, genetic drift, gene flow, recombination, natural selection, non-random mating; without them the population does not evolve. Adaptive radiation: one ancestor gives many adapted forms — Darwin's finches (Galápagos; varied beaks), Australian marsupials.

  • Easy : p + q = 1.
  • Medium : 0.49 + 0.42 + 0.09 = 1.
  • Exam-type (CET) : H–W: no evolution.
Remember

S-D-D: stabilising = stay, directional = drift to one side, disruptive = divide.

Common mistake and CET trap

‘Stabilising selection drives evolution’ is wrong. Trap: ‘p² = heterozygotes’ is wrong (2pq).

Shortcut

Memory clue : "2pq = heterozygous".

Spot the difference

TypeResult
StabilisingMean kept
DirectionalShifts to one end
DisruptiveTwo peaks

Practice questions

Easy
  1. 1Hardy–Weinberg equation?
  2. 2If q = 0.4, p = ?
  3. 3If q = 0.5, aa = ?
Medium
  1. 4Industrial melanism is which type?
  2. 5Seed-cracker finches?
  3. 6Example of adaptive radiation?
Challenging
  1. 7With none of the disturbing factors?
  2. 82pq represents?
Show answers (try them yourself first)
  1. 1p² + 2pq + q² = 1.
  2. 20.6.
  3. 30.25.
  4. 4Directional.
  5. 5Disruptive.
  6. 6Darwin's finches.
  7. 7Population does not evolve.
  8. 8Heterozygotes.

Evidences of evolution

From daily life

A family resemblance reveals kinship; body structure reveals kinship among animals.

Simple definition

Palaeontology = study of fossils. Homologous = similar structure, different function. Analogous = similar function, different structure.

EvidencesEvidences of evolutionHomologousAnalogousVestigialSame structure, different functionSame function, different structureRemnants; appendix, coccyxDivergent evolutionConvergent evolutionPalaeontology: fossils; older layers = primitive; moulds, casts, compressionsConnecting links: Archaeopteryx (reptile↔bird), SeymouriaArchaeopteryx: teeth, long tail, claws + feathers, wings (1861, Bavaria)Homologous: forelimbs of bat, whale, horse, man; bael thornsAnalogous: insect and bird wings; octopus and mammal eyeVestigial: wisdom teeth, nictitating membrane, appendixMolecular: cells, DNA/RNA, ATP, same genetic code in allChimp–human DNA difference 2.5%; monkey–human 10%

In the figure : Homologous, analogous and vestigial organs.

Rule 1 : Fossils (palaeontology) — Fossils = remains of past organisms; the most direct evidence; older layers hold primitive forms, newer layers advanced ones. Types: moulds (impression in a cavity), casts (minerals filling a mould), compressions (carbon film), ice-preserved (Woolly Mammoth, Siberia), amber (insects in resin). A connecting link shows traits of two groups — Archaeopteryx (reptile ↔ bird; Jurassic, Bavaria 1861): teeth, long tail, claws, scales (reptilian) + feathers, wings, beak (avian); Huxley: ‘glorified reptiles’. Another: Seymouria (amphibian ↔ reptile).

  • Easy : Archaeopteryx = reptile + bird.
  • Medium : Older layer = primitive.
  • Exam-type (CET) : Amber = resin.

Rule 2 : Morphology, embryology, molecular evidences — Homologous (same origin, different function): forelimbs of bat, whale, horse, man, bird; bougainvillea thorn and cucurbita tendril → divergent evolution/adaptive radiation; common ancestry. Analogous (different origin, same function): wings of insects and birds; octopus and mammal eye; penguin and dolphin flippers → convergent evolution; do not show ancestry. Vestigial (rudimentary, non-functional): wisdom teeth, nictitating membrane, coccyx, vermiform appendix. Molecular: cells, DNA/RNA, ATP, the same genetic code; chimp–human DNA difference 2.5%, monkey–human 10%.

  • Easy : Homologous = divergent.
  • Medium : Analogous = convergent.
  • Exam-type (CET) : Vestigial = remnant.
Remember

H-D, A-C: homologous-divergent, analogous-convergent.

Common mistake and CET trap

‘Insect and bird wings are homologous’ is wrong (analogous). Trap: ‘analogous organs show common ancestry’ is wrong.

Shortcut

Memory clue : "Homo = same origin; analo = same job".

Spot the difference

PointHomologousAnalogous
StructureSimilarDifferent
FunctionDifferentSimilar
EvolutionDivergentConvergent

Practice questions

Easy
  1. 1Study of fossils?
  2. 2Archaeopteryx links?
  3. 3Homologous example?
Medium
  1. 4Analogous example?
  2. 5Vestigial example?
  3. 6Divergent evolution applies to?
Challenging
  1. 7Chimp–human DNA difference?
  2. 8What is amber?
Show answers (try them yourself first)
  1. 1Palaeontology.
  2. 2Reptiles and birds.
  3. 3Forelimbs of bat and man.
  4. 4Insect and bird wings.
  5. 5Wisdom teeth / appendix.
  6. 6Homologous organs.
  7. 72.5%.
  8. 8Hardened resin.

Geological time scale

From daily life

Earth's history is like a huge book; each era is a chapter.

Simple definition

The geological time scale divides Earth's history into eras → periods → epochs, measured in million years ago (mya).

Geological time scaleGeological time scale (mya)Cenozoic 0–65Mesozoic 65–225Palaeozoic 225–600Proterozoic 600–1600Archaeozoic 1600–3800Cenozoic: age of mammals; modern man; angiospermsMesozoic: age of reptiles, Cretaceous (65–135), Jurassic, Triassic65 mya: dinosaurs extinct; placental mammals risePalaeozoic: Permian, Carboniferous (age of amphibians), Devonian (fishes)Silurian: first land animals; Ordovician: jawless fishesCambrian: trilobites; Proterozoic: early metazoans1600–3800: origin of life; viruses, bacteria, algaeCoelacanth: ‘living fossil’ (1938, South Africa)

In the figure : Eras and key events.

Rule 1 : Eras and periods — As per the book (mya): Cenozoic 0–65 (age of mammals; angiosperms; man), Mesozoic 65–225 (age of reptiles; Cretaceous 65–135, Jurassic 135–165, Triassic 165–225), Palaeozoic 225–600 (Permian 225–280, Carboniferous 280–345 age of amphibians, Devonian 345–400 age of fishes, Silurian 400–440, Ordovician 440–500, Cambrian 500–590), Proterozoic 600–1600, Archaeozoic 1600–3800 (origin of life). Eras ended with major environmental changes and extinctions.

  • Easy : Cenozoic: mammals; Mesozoic: reptiles.
  • Medium : Carboniferous: amphibians.
  • Exam-type (CET) : Devonian: fishes.

Rule 2 : Sequence of life — Life began in the sea; Cambrian: trilobites; Ordovician: first jawless fishes; Silurian: first land animals and plants (ferns); Devonian: fishes diversify; amphibians; Carboniferous: amphibians, first reptiles, coal forests; Mesozoic: dinosaurs, first birds, Archaeopteryx, dinosaurs extinct at 65 mya; Cenozoic: mammals, primates, man. The coelacanth (a lobe-fin fish) was caught in South Africa in 1938 = a living fossil.

  • Easy : 65 mya = dinosaurs ended.
  • Medium : Coelacanth = living fossil.
  • Exam-type (CET) : Cambrian: trilobites.
Remember

C-M-P-P-A: Cenozoic, Mesozoic, Palaeozoic, Proterozoic, Archaeozoic (new → old).

Common mistake and CET trap

‘Dinosaurs lived in the Cenozoic’ is wrong (Mesozoic). Trap: fishes diversified in the Devonian.

Shortcut

Memory clue : "C-M-P-P-A = ‘Can My Pet Pig Act?’".

Spot the difference

EraAge
CenozoicMammals
MesozoicReptiles
PalaeozoicAmphibians / fishes

Practice questions

Easy
  1. 1Order of eras (new to old)?
  2. 2Age of reptiles?
  3. 3When did dinosaurs go extinct?
Medium
  1. 4Age of amphibians?
  2. 5First jawless fishes?
  3. 6When was coelacanth found?
Challenging
  1. 7Archaeopteryx era?
  2. 8Origin of life era?
Show answers (try them yourself first)
  1. 1Cenozoic, Mesozoic, Palaeozoic, Proterozoic, Archaeozoic.
  2. 2Mesozoic.
  3. 3~65 mya.
  4. 4Carboniferous.
  5. 5Ordovician.
  6. 61938.
  7. 7Mesozoic (Jurassic).
  8. 8Archaeozoic.

Human evolution

From daily life

The human journey began with a tree-dweller learning to stand and walk upright.

Simple definition

Human evolution = journey from ape-like ancestors to modern Homo sapiens; key changes: bipedalism, opposable thumb, larger brain.

Human evolutionHuman evolutionDryopith.Ramapith.Australop.H. habilisH. erectusNeanderthalH. sapiensapeman-like450–600650–80090014001450Cranial capacity (cc)Dryopithecus: ape-like; Ramapithecus: man-like (Shivalik)Australopithecus: ‘man with ape brain’ (Taung, S. Africa)H. habilis: ‘handy man’ (Olduvai); toolsH. erectus: Java/Peking ‘ape man’; fire, meatNeanderthal: Germany; burial; ~1400 cc; 100,000–40,000 yH. sapiens: Africa; modern man; ~1450 ccTrends: bipedal, opposable thumb, larger brain, languageAncestor: tree-dwelling shrew-like animal

In the figure : Human evolution sequence and cranial capacity.

Rule 1 : Ancestors and sequence — The ancestor is thought to be a tree-dwelling shrew-like animal. Sequence: Dryopithecus (chimp-like; Africa) → Ramapithecus (man-like; Shivalik, India) → Australopithecus (‘ape brain’, man-like; Taung, S. Africa; 450–600 cc) → Homo habilis (‘handy man’; Olduvai Gorge; 650–800 cc; tools) → Homo erectus (Java/Peking ‘ape man’; ~900 cc; fire, meat) → Neanderthal (Germany; ~1400 cc; 100,000–40,000 y; buried the dead) → Homo sapiens (modern; ~1450 cc; Africa).

  • Easy : Cranial capacity rises: 450 → 1450 cc.
  • Medium : Habilis = tools.
  • Exam-type (CET) : Neanderthal = burial.

Rule 2 : Major trends — Key changes: larger and more complex brain (cranial capacity), bipedal locomotion and upright posture, opposable thumb (grip), flatter face, large frontal lobe (high forehead), language and culture. Intelligence needed matching bodily development. Chimp–human DNA differs by only 2.5%. Brain complexity (frontal lobe), not size alone, determines intelligence.

  • Easy : Bipedal + thumb + brain.
  • Medium : 2.5% DNA difference.
  • Exam-type (CET) : Frontal lobe = intelligence.
Remember

D-R-A-H-E-N-S: Dryo, Rama, Austral, Habilis, Erectus, Neanderthal, Sapiens.

Common mistake and CET trap

‘Humans descended from chimpanzees’ is wrong (common ancestors). Trap: Neanderthal is a side branch/predecessor.

Shortcut

Memory clue : "Habilis = handy; erectus = fire and meat".

Spot the difference

NameCranial capacity
Australopithecus450–600 cc
H. habilis650–800 cc
H. erectus900 cc
Neanderthal1400 cc
H. sapiens1450 cc

Practice questions

Easy
  1. 1Fossil from Shivalik hills?
  2. 2‘Handy man’?
  3. 3Man with ape brain?
Medium
  1. 4Java ape man?
  2. 5Neanderthal cranial capacity?
  3. 6Name of modern man?
Challenging
  1. 7One trend?
  2. 8Where is Olduvai Gorge?
Show answers (try them yourself first)
  1. 1Ramapithecus.
  2. 2Homo habilis.
  3. 3Australopithecus.
  4. 4Homo erectus.
  5. 5~1400 cc.
  6. 6Homo sapiens.
  7. 7Bipedal locomotion.
  8. 8Tanzania.

Quick revision of the whole lesson

ConceptKey fact
OriginOparin–Haldane; Miller 1953; RNA World
TheoriesLamarck, Darwin, de Vries
MechanismsDrift, gene flow, allopatric/sympatric
Selection / H–Wp² + 2pq + q² = 1
EvidencesHomologous, analogous, vestigial
Time scaleCenozoic → Archaeozoic
HumanAustralopithecus → H. sapiens

🎯 Most important points for the exam

  • Miller–Urey, RNA World.
  • Lamarck, Darwin, de Vries.
  • Allopatric / sympatric speciation.
  • Hardy–Weinberg.
  • Homologous / analogous.
  • Geological eras.
  • Order of human evolution.
Study mantra

Understand the concept → draw the figure → memorise the key points → solve questions yourself.