Q.Distinguish between homologous organs and analogous organs, giving two examples of each. What does the presence of homologous organs across different species tell us about their evolutionary relationship, and what does the presence of analogous organs tell us instead?

Showing the 12 most recent of 26 on this concept.

1. CBSE 2026Set 57/2/11 markMCQ
   Q.What conclusion can be drawn if the forelimbs of an aquatic animal and a terrestrial animal have similar anatomical structure ? (A) Live in same habitat (B) Share common ancestors (C) Forelimbs perform same functions (D) Forelimbs are analogous

   ›Reveal solutionSolution

   Similar anatomical structures in the forelimbs of different animals, despite varied functions and habitats, indicate that they share a common ancestor.

   When we observe the natural world, one of the most fascinating aspects is the diversity of life, yet beneath this diversity, there are often striking similarities. The question of why different animals, living in vastly different environments and performing different tasks, might possess forelimbs with a fundamentally similar anatomical structure is central to understanding evolutionary biology. This observation provides powerful evidence for how life on Earth has changed over millions of years.

   Consider the forelimb of a whale, an aquatic mammal, and the forelimb of a human, a terrestrial mammal. Superficially, they look very different: a whale's flipper is adapted for swimming, while a human's arm is adapted for grasping, manipulating, and walking (in our distant ancestors). However, if we examine their internal bone structure, we find a remarkable resemblance. Both possess a humerus (upper arm bone), radius and ulna (forearm bones), carpals (wrist bones), metacarpals (palm bones), and phalanges (finger bones), arranged in a very similar pattern.

   Important

   Structures that have the same basic structural plan but perform different functions are called homologous structures. They are a key piece of evidence for evolution.

   This similarity in basic anatomical structure, despite differences in function and habitat, is not a coincidence. It suggests that these animals inherited this fundamental limb design from a common ancestor. Over vast periods, as different groups of descendants adapted to various environments and lifestyles—some returning to water, others remaining on land—their forelimbs underwent modifications. These modifications allowed them to perform specialized functions like swimming, flying, running, or grasping, but the underlying blueprint remained. This process, where structures diverge from a common form to serve different functions, is known as divergent evolution.

   Let's evaluate the given options based on this understanding:

   • ** (A) Live in same habitat:** This is incorrect. The premise of the question explicitly states an aquatic animal and a terrestrial animal, meaning they live in different habitats.
   • ** (C) Forelimbs perform same functions:** This is also incorrect. A whale's flipper is for swimming, while a human's arm is for grasping and manipulating. Their functions are distinct, even if both involve movement.
   • ** (D) Forelimbs are analogous:** This is incorrect. Analogous structures are those that perform similar functions but have different basic structural designs. For example, the wings of a bird and the wings of an insect are analogous; both are used for flight, but their underlying anatomy is entirely different. In our case, the forelimbs have similar basic structures, making them homologous, not analogous.

   Note

   The distinction between homologous and analogous structures is crucial. Homologous structures point to common ancestry, while analogous structures point to convergent evolution (where different species evolve similar traits independently due to similar environmental pressures).

   • ** (B) Share common ancestors:** This is the correct conclusion. The presence of similar basic anatomical structures, like the forelimbs of an aquatic and a terrestrial animal, despite their different functions and habitats, is the hallmark of homologous organs. Homologous organs provide strong evidence that these diverse species have evolved from a common ancestral form, with modifications occurring over time to suit their specific environmental niches.

   ✓Final answer

   In short, if the forelimbs of an aquatic and a terrestrial animal have similar anatomical structures, it indicates that they share common ancestors from which these structures were inherited and then modified over evolutionary time.

2. CBSE 2026Set A1 markMCQ
   Q.Which of the following are examples of homologous organs in animals?

   (a) Eyes of octopus and human

   (b) Sweet potato and potato

   (c) Flippers of penguins and dolphins

   (d) Heart of reptiles and mammals

   ›Reveal solutionSolution

   Homologous organs share a common ancestral structure though they may do different jobs; penguin and dolphin flippers fit this.

   Homology reflects common ancestry: the forelimbs of vertebrates (penguin flipper, dolphin flipper, human arm, etc.) share the same underlying bone pattern (humerus, radius, ulna, carpals) inherited from a common ancestor — divergent evolution. Octopus and human eyes, and flippers of a marlin vs. a whale used only for the same function, are analogous (convergent). Sweet potato and potato is a plant example of analogy. So the correct homologous pair here is the flippers of penguins and dolphins.

   ✓Final answer

   (C) Flippers of penguins and dolphins.

3. CBSE 2026Set ZOOLOGY1 markMCQ
   Q.The wings of butterflies and the wings of birds are the examples of which of the following?

   (a) Homologous organs

   (b) Analogous organs

   (c) Vestigial organs

   (d) Asymmetric organs

   ›Reveal solutionSolution

   Butterfly wings and bird wings are analogous organs: same function, different evolutionary origin (convergent evolution).

   Analogous organs are structures that perform the same function in different organisms but have a different basic structure and developmental origin, arising through convergent evolution in response to similar environmental/functional demands. The wings of a butterfly (a membranous extension of the exoskeleton, an insect structure) and the wings of a bird (a modified forelimb built on a vertebrate pentadactyl bone framework) both serve the function of flight, but they are structurally and developmentally completely different and did not arise from a common ancestral structure. This is in contrast to homologous organs (e.g., forelimbs of frog, lizard, bird, and man), which share the same basic structure/origin but may perform different functions.

   ✓Final answer

   (b) Analogous organs.

4. CBSE 2026Set ANNUAL1 markMCQ
   Q.Wings of bat and wings of insects have similar functions, so they are examples of

   (a) Homologous organs

   (b) Analogous organs

   (c) Vestigeal organs

   (d) Connecting links

   ›Reveal solutionSolution

   Organs that look/function alike but arose independently from different structures are analogous organs — evidence of convergent evolution.

   Homologous organs share the same basic structure and developmental origin even though their functions may differ (e.g., the forelimbs of a human, cat, whale and bat all share the same bone plan). Analogous organs, in contrast, perform the same function but have different structural origin and evolve independently in unrelated groups facing similar environmental pressures — this is convergent evolution.

   Bat wings are modified forelimbs (skin stretched over elongated finger bones), while insect wings are outgrowths of the exoskeleton (chitinous cuticle) with no relation to limbs at all. Both let their owners fly, but the underlying structures share no common ancestry — a textbook example of analogous organs, alongside eyes of octopus and mammals.

   ✓Final answer

   (b) Analogous organs.

5. CBSE 2026Set ANNUAL1 mark
   Q.Mention the type of evolution that has brought the similarity as seen in potato tuber and sweet potato.

   ›Reveal solutionSolution

   Potato tuber (a modified underground STEM) and sweet potato (a modified ADVENTITIOUS ROOT) look and function alike (as storage organs) despite arising from different plant parts — this is convergent evolution, producing analogous structures.

   When two organisms/structures resemble each other closely due to adaptation to a similar function or environment, even though their developmental/evolutionary origin is different, it is called convergent evolution and the resulting structures are termed analogous. The potato tuber develops from underground stem tissue (it bears nodes, internodes, and axillary buds/'eyes'), while the sweet potato is a modified adventitious root. Both evolved a swollen, starch-storing form independently to serve the same storage function, illustrating convergent evolution — as opposed to divergent evolution, which produces homologous organs from a common ancestral structure (e.g. vertebrate forelimbs).

   ✓Final answer

   Convergent evolution (the tuber and the root are analogous organs).

6. CBSE 2026Set SEM31 markMCQ
   Q.Match Column-I with Column-II and select the correct option : Column-I : i) Phylloclade of Opuntia, stem tendril of Passiflora ii) Archaeopteryx iii) Sphenodon, Limulus iv) Bat wings, insect wings v) Ornithorhynchus ; Column-II : a) Connecting link between reptiles and mammals b) Living fossils c) Analogous organs d) Missing link between reptiles and birds e) Homologous organs.

   (a) i-e, ii-c, iii-d, iv-b, v-a

   (b) i-b, ii-c, iii-a, iv-e, v-d

   (c) i-e, ii-b, iii-d, iv-c, v-a

   (d) i-b, ii-e, iii-a, iv-c, v-d

   ›Reveal solutionSolution

   Correct evolutionary matches: stem modifications (Opuntia phylloclade, Passiflora tendril) = homologous organs; Archaeopteryx = missing link between reptiles and birds; Sphenodon & Limulus = living fossils; bat wing & insect wing = analogous organs; Ornithorhynchus (platypus) = connecting link between reptiles and mammals. Among the options, (c) is anchored on these definitive pairings.

   The biology of each item:

   • i) Phylloclade of Opuntia & stem tendril of Passiflora → (e) Homologous organs: both are modifications of the stem — same origin, different functions → homologous.
   • ii) Archaeopteryx → (d) Missing link between reptiles and birds: it had reptilian teeth/tail and bird-like feathers.
   • iii) Sphenodon, Limulus → (b) Living fossils: ancient forms surviving almost unchanged.
   • iv) Bat wings & insect wings → (c) Analogous organs: different origins, same function (flight) → analogous.
   • v) Ornithorhynchus (duck-billed platypus) → (a) Connecting link between reptiles and mammals: an egg-laying mammal.

   Option (c) correctly places the three unambiguous anchors — i-e (homologous), iv-c (analogous), v-a (reptile–mammal link) — and is the intended key.

   (Honesty note: the given options do not contain a fully perfect permutation; option (c) uniquely carries the three definitive matches above, so it is selected as the best/intended answer.)

   Based on NCERT/CBSE Class 12 Biology Evolution (evidences of evolution).

   ✓Final answer

   (c) i-e, ii-b, iii-d, iv-c, v-a (anchored on homologous organs, analogous organs, and the reptile–mammal connecting link).

7. CBSE 2025Set 57/5/11 markMCQ
   Q.Which of the following combinations is a correct example of convergent evolution in Australian marsupials and Placental mammals ? [Australian Marsupials / Placental Mammals] (A) Lemur / Spotted cuscus (B) Tasmanian tiger cat / Anteater (C) Bobcat / Lemur (D) Numbat / Anteater

   ›Reveal solutionSolution

   Convergent evolution produces similar adaptations in unrelated lineages facing similar ecological pressures. Numbat and Anteater both evolved specialized ant/termite-eating features independently, making (D) correct.

   Convergent evolution occurs when distantly related organisms independently evolve similar traits because they occupy similar ecological niches or face similar environmental challenges. The classic textbook example compares Australian marsupials (which evolved in isolation on the Australian continent) with placental mammals from other continents that filled analogous roles.

   The key is to identify pairs where the Australian marsupial and the placental mammal share a similar lifestyle and corresponding adaptations, despite their evolutionary distance.

   Let me examine each option:

   1. Option (A): Lemur / Spotted cuscus

      This pairing is backwards. Lemurs are placental mammals (primates from Madagascar), while spotted cuscuses are Australian marsupials. Both are arboreal and somewhat similar in lifestyle, but the question asks for [Australian Marsupial / Placental Mammal] in that order. The order is reversed here.

   2. Option (B): Tasmanian tiger cat / Anteater

      The Tasmanian tiger cat (actually called the spotted-tailed quoll) is a carnivorous marsupial that hunts small vertebrates. Anteaters are highly specialized placental mammals with elongated snouts, long sticky tongues, and powerful claws for breaking into ant and termite nests. These occupy very different ecological niches—one is a generalist carnivore, the other an insectivore specialist. Not a good match.

   3. Option (C): Bobcat / Lemur

      Bobcats are placental mammals (wild cats from North America), and lemurs are also placental mammals (primates). This pairing doesn't even include an Australian marsupial, so it cannot demonstrate marsupial-placental convergence.

   4. Option (D): Numbat / Anteater

      The numbat is an Australian marsupial that feeds almost exclusively on termites. It has evolved a long, sticky tongue, a pointed snout, and specialized behaviors for extracting termites from wood. Anteaters (placental mammals from Central and South America) show remarkably similar adaptations: elongated snouts, long sticky tongues, reduced teeth, and powerful digging claws—all for the same diet of ants and termites. This is textbook convergent evolution.

   Tip

   In convergent evolution questions, focus on functional similarity driven by diet and lifestyle, not just superficial appearance. Ant-eaters and termite-eaters across different continents are classic examples.

   Watch out

   Don't confuse the order of the pairing. The question format specifies [Australian Marsupial / Placental Mammal], so the first organism must be the marsupial.

   ✓Final answer

   The correct option is (D) — Numbat (Australian marsupial) and Anteater (placental mammal) both independently evolved specialized adaptations for eating ants and termites.

8. CBSE 2025Set F1 markMCQ
   Q.Which of the following is an example of analogous organs?

   (a) Wings of birds and butterfly

   (b) Tail of dog and cat

   (c) Wing of bat and hand of man

   (d) All of these

   ›Reveal solutionSolution

   Wings of a bird and a butterfly are analogous — same function, different origin (convergent evolution).

   Analogous organs have a similar FUNCTION but a different structural origin (developmental/anatomical basis); they illustrate convergent evolution. The wing of a bird (a modified forelimb with feathers and bones) and the wing of a butterfly (a thin cuticular outgrowth of the exoskeleton) both serve flight yet arise from entirely different structures — hence analogous. In contrast, the wing of a bat and the hand of a man share the same underlying bone plan and are HOMOLOGOUS organs (divergent evolution). Therefore option (A) is the correct example of analogy.

   ✓Final answer

   (A) Wings of birds and butterfly.

9. CBSE 2025Set F1 markMCQ
   Q.Convergent evolution is demonstrated by which of the following?

   (a) Bacteria and protozoa

   (b) Rat and dog

   (c) Starfish and cuttle fish

   (d) Dogfish and whale

   ›Reveal solutionSolution

   Dogfish and whale show convergent evolution (analogous streamlined bodies).

   Convergent evolution occurs when unrelated organisms independently evolve similar features because they live in similar environments; such similar structures are analogous. A dogfish is a cartilaginous fish while a whale is an aquatic mammal, yet both have evolved a streamlined, fusiform body with fin-like appendages for efficient swimming. Since they belong to very different groups but look alike due to aquatic life, they illustrate convergent evolution.

   ✓Final answer

   (d) Dogfish and whale.

10. CBSE 2025Set A1 mark
    Q.Fill in the blank with the correct answer: Placental wolf and Tasmania wolf similar to a corresponding ______.

    ›Reveal solutionSolution

    Similar body forms arising independently in unrelated lineages, due to adaptation to similar habitats, is convergent evolution.

    The placental wolf (Canis, found in North America) and the Tasmanian wolf/thylacine (a marsupial, found in Australia) belong to very different mammalian lineages — one placental, one marsupial — that have been separated for tens of millions of years. Yet both evolved a strikingly similar wolf-like body plan, skull shape, and predatory lifestyle because they occupied similar ecological niches in their respective, geographically isolated regions. This is a textbook example of convergent evolution, where unrelated organisms evolve analogous structures/forms under similar selection pressures, rather than from shared ancestry (which would be homology/divergent evolution).

    ✓Final answer

    Convergent evolution (they are analogous, not homologous, structures).

11. CBSE 2025Set ANNUAL1 markMCQ
    Q.Which of the following are homologous organs?

    (a) Trunk of an elephant and forelimbs of a monkey

    (b) Wings of bird and wings of butterfly

    (c) Cat's paw and forelimbs of a horse

    (d) Wings of a bat and wings of a cockroach

    ›Reveal solutionSolution

    Homologous organs share the same basic structural/developmental origin from a common ancestor but may perform different functions (divergent evolution); analogous organs perform the same function but arose independently from different origins (convergent evolution).

    A cat's paw and a horse's forelimb are both built on the same pentadactyl limb skeletal plan (humerus-radius/ulna-carpals-digits) inherited from a common tetrapod ancestor, even though a cat's paw is used for walking/grasping and a horse's limb for running on a single toe (hoof) - this is the hallmark of homology.

    By contrast: a bird's wing and a butterfly's wing both enable flight but arose from completely different structures (a modified vertebrate forelimb vs a chitinous outgrowth of an insect's exoskeleton) - they are analogous, not homologous. Similarly a bat's wing (modified forelimb) and a cockroach's wing (exoskeletal outgrowth) are analogous. An elephant's trunk (a modified nose/upper lip) and a monkey's forelimb do not share a common origin either, so they are not homologous.

    ✓Final answer

    (c) Cat's paw and forelimbs of a horse.

12. CBSE 2025Set ANNUAL1 mark
    Q.Would you consider the wings of a butterfly and a bat as homologous or analogous?

    ›Reveal solutionSolution

    Homology depends on shared origin/structure, not shared function - so despite performing the same function (flight), butterfly wings and bat wings are analogous, not homologous, because their underlying structures and evolutionary origins are completely different.

    Homologous organs have the same basic structural plan and arise from a common ancestral structure, even if they now serve different functions (e.g. divergent evolution, as in the pentadactyl forelimbs of different vertebrates). Analogous organs, by contrast, may look or function similarly but have entirely different developmental origins, having evolved independently to meet a similar environmental need (convergent evolution).

    A butterfly's wing is a thin membranous outgrowth of its chitinous exoskeleton (an insect, invertebrate structure), while a bat's wing is a modified vertebrate forelimb - a skeleton of arm and finger bones stretched with a skin membrane. Both evolved the ability to fly independently, from very different starting structures, so they are analogous organs, not homologous.

    ✓Final answer

    Analogous - they serve the same function (flight) but have entirely different structural origins (exoskeletal outgrowth vs modified forelimb), so they arose by convergent evolution, not from a common ancestral wing.