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The evolution of similar features in unrelated groups such as Australian marsupials (thylacine, marsupial mole, wombat) resembling placental mammals (wolf, mole, mouse) is called ________.

R
Solution written and verified by Roshan, science educator with 5 years of experience teaching NEET and JEE aspirants. Last reviewed September 2026.
Options
1
Divergent evolution
2
Adaptive radiation
3
Convergent evolution
4
Co-evolution
Correct Answer
Convergent evolution
Solution
1

Marsupials in Australia evolved similar forms to placental mammals elsewhere:

Thylacine ≈ Wolf | Marsupial mole ≈ Placental mole | Wombat ≈ Rodent

2

These are UNRELATED organisms that evolved SIMILAR features = CONVERGENT EVOLUTION

Produces ANALOGOUS structures (same function, different origin)

Answer: Convergent evolution

Convergent evolution: unrelated organisms → similar features (analogous)
Marsupials ≈ Placentals despite being unrelated — same ecological niches selected similar forms
Theory: Evolution
1. Convergent vs Divergent Evolution

Convergent: unrelated → similar (analogous organs). Divergent: related → different (homologous organs). Key test: Are they structurally similar (convergent) or anatomically similar beneath appearance (divergent)? Dolphin fin vs shark fin: look similar, but dolphin fin has hidden humerus-radius-ulna = homologous to forelimb = actually divergent at deeper level, while the STREAMLINED SHAPE convergent.

2. Australian Marsupials — Adaptive Radiation + Convergent Evolution

Australia isolated from other continents early → marsupials filled all ecological niches without placental mammal competition. Same niches filled by placentals elsewhere, but independently by marsupials: Wolf-like predator: thylacine (marsupial wolf/Tasmanian tiger — extinct 1936). Mole-like burrower: marsupial mole (Notoryctes). Mouse-like omnivore: dasyures. Anteater-like: numbat. Rabbit-like: bilby. These parallel ecomorphs demonstrate both adaptive radiation (one marsupial ancestor → many species) AND convergent evolution (marsupials converged on placental forms).

3. Molecular Evidence for Convergent Evolution

DNA sequencing confirms convergent evolution: species appearing similar morphologically are actually phylogenetically distant when their genomes are compared. Famous example: convergent evolution of eyes. Vertebrate eyes and cephalopod (octopus) eyes appear remarkably similar structurally but were proven to have evolved independently (the key gene Pax6 controls eye development in both lineages but the final structures arose independently). Molecular clock comparisons confirm unrelated ancestry despite morphological similarity.

4. Co-evolution Distinguished

Co-evolution: two or more species evolving in response to each other (reciprocal evolutionary change). Examples: flowers and pollinators (long orchid spurs co-evolved with long-tongued hawkmoths), hosts and parasites (immune system vs pathogen evolution), predator and prey (cheetah speed vs gazelle speed). Convergent evolution involves similar environmental pressures from the PHYSICAL environment; co-evolution involves evolutionary responses to each OTHER.

Frequently Asked Questions
1. What is convergent evolution? ⌄
Convergent evolution: unrelated species independently evolve similar features (analogous structures) in response to similar environmental pressures or ecological roles. They do NOT share recent common ancestry for these features. Results in analogous organs. Examples: wings of birds and insects (both for flying, different origin), eyes of vertebrates and cephalopods (similar structure, evolved independently), streamlined body of dolphins (mammals) and sharks (fish).
2. What is the difference between convergent and divergent evolution? ⌄
Convergent evolution: different organisms → similar features (analogous). Results from similar selection pressures. Unrelated organisms become MORE similar. Divergent evolution: related organisms → different features (homologous). Results from different selection pressures. Related organisms become LESS similar (adaptive radiation). Example of divergent: Darwin's finches (same ancestor, different beaks). Example of convergent: dolphin and shark (different ancestors, similar body form).
3. What is adaptive radiation? ⌄
Adaptive radiation: rapid divergent evolution of one ancestral species into many species occupying different ecological niches. Classic examples: Darwin's finches (Galapagos — 14 finch species from one ancestor with different beaks). Australian marsupials (one marsupial ancestor radiated into wolf, mole, anteater, etc. niches). Mammals after dinosaur extinction (rapid radiation into diverse niches).
4. What are analogous vs homologous organs in evolution? ⌄
Analogous: same function, different evolutionary origin, convergent evolution. Wings of birds vs insects. Eyes of vertebrates vs octopus. Homologous: same evolutionary origin (common ancestor), different functions, divergent evolution. Forelimbs of vertebrates. Analogous organs are evidence of convergent evolution; homologous organs are evidence of common ancestry.
5. Give more examples of convergent evolution. ⌄
Ichthyosaurs (extinct reptiles) + dolphins (mammals) + sharks (fish): all streamlined for aquatic predation. Cactus (Americas) + Euphorbia (Africa): both succulent stem plants in deserts (not related, but evolved similar adaptations to water scarcity). Flying squirrel + sugar glider (marsupial): both have skin flaps for gliding. Saber-toothed cats (extinct) + marsupial lion: both had enlarged saber canine teeth for similar prey.
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