Biology · Evolution · NEET
Same in STRUCTURE, not in function. Homologous organs share the same internal design and the same origin (they come from a common ancestor), but they may perform very different functions. Do not get confused: matching the FUNCTION is the trap. A human hand and a bat wing look totally different and do different jobs, but the bones inside are the same pattern, so they are homologous.
Because the underlying bone plan is identical. Human, whale, bat and cheetah forelimbs all contain humerus, radius, ulna, carpals, metacarpals and phalanges. The SAME structure got shaped in different directions to suit different needs (grasping, swimming, flying, running). Same starting design + different final use = homology. NCERT calls this divergent evolution.
Divergent evolution is when ONE common ancestral structure changes along DIFFERENT directions in different species, because each species adapts to a different need or habitat. The result is homologous organs. Think of it like one road splitting into many paths. Homology is the evidence; divergent evolution is the process behind it.
Yes. Both are forelimbs built on the same vertebrate bone pattern inherited from a common ancestor, even though one flies and one swims. This is a favourite NEET trap: a moth wing is NOT homologous to a bird wing (it is analogous — same function, different design). Only structures with the same bone plan are homologous.
Yes. In plants, the thorn of Bougainvillea and the tendril of Cucurbita are both modifications of the same organ (they arise from the same position), so they are homologous even though a thorn protects and a tendril climbs. This is NCERT's standard plant example of homology and divergent evolution.
Yes. NCERT states clearly: 'Homology indicates common ancestry.' If two animals share the same basic structural plan, it means they inherited that plan from a shared ancestor. This makes homologous organs an anatomical evidence for evolution. Analogous organs, by contrast, do NOT prove common ancestry.
These are totally different topics that share a word. Homologous ORGANS (Evolution chapter) are body parts with the same structure but different function, showing common ancestry. Homologous CHROMOSOMES (Cell Division chapter) are a matching pair of chromosomes, one from each parent, that pair up during meiosis. Do not mix them in the exam.
Which of the following structures is homologous to the wing of a bird?
The similarity of bone structure in the forelimbs of many vertebrates is an example of
Among the following sets of examples for divergent evolution, select the incorrect option:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Homologous organs are organs that have the same fundamental structure and the same developmental origin (from a common ancestor) but may perform different functions. NCERT's example is the forelimbs of whales, bats, cheetah and humans, which all have humerus, radius, ulna, carpals, metacarpals and phalanges.
Homology is the pattern (the evidence we observe) and divergent evolution is the process that produces it. When one ancestral structure evolves in different directions in different species, we get homologous organs. So homology is based on divergent evolution.
Animals: forelimbs of humans, whales, bats and cheetah (all same bone plan). Plants: thorn of Bougainvillea and tendril of Cucurbita, which are both modifications of the same organ. Both sets show divergent evolution.
Because homology indicates common ancestry. If different species share the same basic structural plan, the simplest explanation is that they inherited it from a shared ancestor and then modified it for different uses. This anatomical evidence supports the theory of evolution.
Homologous organs = same structure, different function, common ancestry, product of divergent evolution (e.g. forelimbs of vertebrates). Analogous organs = different structure, same function, no common ancestry, product of convergent evolution (e.g. wings of birds and butterflies).
