Biology · Evolution · NEET
NCERT (Ch 6) groups the evidences as: (1) Paleontological evidence — fossils in different-aged rock sediments; (2) Comparative anatomy and morphology — homologous organs (divergent evolution) and analogous organs (convergent evolution); (3) Embryological evidence — proposed by Haeckel, later disproved by von Baer; (4) Biochemical/molecular evidence — similarities in proteins and genes; (5) Evidence seen in our lifetime — artificial selection (domestication), industrial melanism (peppered moth), and drug/pesticide resistance.
No. This is the most common trap. Analogous organs (like wings of butterfly and bird) look alike and do the same job, but they evolved independently in unrelated lineages. They show convergent evolution and adaptation to a similar environment, NOT descent from a common ancestor. Only homologous organs prove common ancestry.
Fossils are the actual remains or impressions of hard parts of dead organisms preserved in rock sediments. Deeper (older) sediments hold simpler/extinct forms and upper (newer) sediments hold more complex forms. This visible time-ordered record directly shows that life forms changed over millions of years, so fossils are treated as direct paleontological evidence.
Homologous organs have the same basic anatomical plan but different functions (e.g. forelimbs of man, whale, bat, cheetah — all have humerus, radius, ulna, carpals, metacarpals, phalanges). They arise by divergent evolution and prove common ancestry. Analogous organs have different structure but the same function (wings of butterfly and bird). They arise by convergent evolution and only show adaptation, not ancestry.
Homologous structures and biochemical/molecular similarities (shared proteins, similar DNA/genes) are the strongest for common ancestry, because they reflect inherited features from a shared ancestor. Analogy is the weakest for ancestry — it only shows similar function evolving separately.
Partly. Ernst Haeckel proposed embryological support using features like gill slits common to all vertebrate embryos. Karl Ernst von Baer disproved the strong 'recapitulation' idea, noting embryos never pass through the adult stages of other animals. So NCERT mentions it, but exam questions often mark Haeckel's proposal as the disproved/weak one.
Which of the following is NOT evidence for evolution?
Match List I with List II. (a) Adaptive radiation (b) Convergent evolution (c) Divergent evolution (d) Evolution by anthropogenic action | (i) Selection of resistant varieties due to excessive use of herbicides and pesticides (ii) Bones of forelimbs in Man and Whale (iii) Wings of butterfly and birds (iv) Darwin Finches
Try the real previous-year questions from this chapter — each with the answer and a full solution.
For NEET, remember six lines of evidence: paleontological (fossils), comparative anatomy (homology and analogy), embryological, biochemical/molecular, biogeographical, and evolution observed in our own time (artificial selection, peppered moth, drug resistance).
Homologous organs are the result of divergent evolution — the same basic structure adapts along different directions for different functions (e.g. vertebrate forelimbs, thorn and tendril of Bougainvillea and Cucurbita).
Analogous organs result from convergent evolution — different structures evolving the same function (wings of butterfly and bird, eye of octopus and mammal, flippers of penguin and dolphin).
Yes. Industrial melanism in the peppered moth is a real, observed case of natural selection: dark moths survived on soot-darkened trees after industrialisation, showing evolution happening in a short, human-recorded time.
Yes. Homologous structures and molecular/biochemical similarities (similar proteins and DNA) most strongly point to a common ancestor, because these features are inherited rather than independently evolved.
