EVOLUTION · Comparison Tables

1. Chemical evolution vs biological evolution

Two stages in the origin and diversification of life
Feature	Chemical evolution	Biological evolution
Meaning	Formation of organic molecules and first self-replicating systems from non-living matter.	Change in inherited characters and populations across generations.
Context	Early earth and origin of life	After life originated
NCERT evidence / idea	Miller's experiment produced amino acids in simulated primitive-earth conditions.	Natural selection, mutation, recombination, drift and gene flow alter gene frequencies.
Key result	Prebiotic organic compounds and early life	Biodiversity, adaptation and speciation

2. Lamarckism vs Darwinism

Historic explanations of evolution
Point	Lamarckism	Darwinism / natural selection
Main idea	Use and disuse modify organs; acquired characters are inherited.	Heritable variations already occur; individuals with favourable variations leave more offspring.
Source of variation	Need-directed modification during life	Pre-existing heritable variation in a population
Classic giraffe explanation	Repeated stretching lengthened neck and offspring inherited it.	Longer-necked individuals had a survival/reproductive advantage.
Status	Acquired characters are generally not inherited.	Core principle remains central to modern evolutionary theory.

3. Homologous vs analogous organs

Comparative anatomical evidence
Feature	Homologous organs	Analogous organs
Basic plan / origin	Same basic structural plan and origin	Different basic structure and origin
Function	May be different	Similar
Evolutionary pattern	Divergent evolution	Convergent evolution
Examples	Forelimbs of whale, bat, cheetah and human; thorn of Bougainvillea and tendril of Cucurbita.	Wings of birds and butterflies; flippers of penguins and dolphins.

4. Divergent vs convergent evolution

Patterns produced by selection in different lineages
Feature	Divergent evolution	Convergent evolution
Starting point	Common ancestor	Different ancestors
Outcome	Related forms become increasingly different	Unrelated forms independently become similar
Structures produced	Homologous organs	Analogous organs
Example	Darwin's finches radiating from an ancestral finch	Australian marsupials resembling placental mammals

5. Adaptive radiation vs convergent evolution

Do not confuse these related ideas
Point	Adaptive radiation	Convergent evolution
Definition	Evolution of different species from a common ancestor in a geographical area, each adapting to a different niche.	Independent evolution of similar adaptive traits in unrelated groups.
Relationship	A form of divergent evolution	Produces analogy
NCERT example	Darwin's finches of the Galapagos; Australian marsupials	Australian marsupials and placental mammals with similar ecological roles

6. Stabilising vs directional vs disruptive selection

Effects of natural selection on phenotype distribution
Type	Favoured phenotype	Effect on population
Stabilising selection	Intermediate phenotype	Mean remains similar; extremes are selected against.
Directional selection	One extreme	Mean shifts toward the favoured extreme.
Disruptive selection	Both extremes	Intermediate forms are selected against; distribution may split.

7. Hardy-Weinberg equilibrium vs evolutionary change

Population genetics reference point
Feature	Hardy-Weinberg equilibrium	Evolutionary change
Gene pool	Allele frequencies remain constant generation after generation.	Allele frequencies change across generations.
Equation	p² + 2pq + q² = 1; p + q = 1	Observed frequencies deviate from equilibrium expectations.
Disturbing factors	Absent	Gene migration/flow, genetic drift, mutation, recombination and natural selection.

Exam cueFounder effect is a type of genetic drift in which a new population begins with only a few individuals.

8. Ape vs human

Key NCERT points in human evolution
Group	NCERT point
Dryopithecus	More ape-like; lived about 15 mya.
Ramapithecus	More man-like; lived about 15 mya.
Australopithecines	East African grassland hominids, likely ate fruit and hunted with stone weapons.
Homo habilis	Brain capacity 650-800 cc; probably did not eat meat.
Homo erectus	About 1.5 mya; brain around 900 cc; ate meat.
Homo sapiens	Modern humans; Neanderthal man had brain size about 1400 cc and lived 100,000-40,000 years ago.