MPSC 2026 Prelims Paper-I · Question 35 of 100

Correct — option (2), F. Clements (1916). The American plant ecologist Frederic E. Clements proposed the term 'biome' in 1916, the same year as his major work on plant succession, and the idea was developed further in Bio-Ecology, which he wrote with the animal ecologist Victor Shelford in 1939. The point of the term was integration. Plant ecologists at the time worked with the plant formation, animal ecologists with the animal community, and the two were studied separately; the biome was proposed as the larger unit that takes in both — a major regional community of plants and animals together, occupying a broad climatic zone and identified by its dominant vegetation type. Tropical rainforest, savanna, desert, temperate grassland, temperate deciduous forest, boreal forest and tundra are biomes in this sense. The question is a straight attribution, and it is best answered by the elimination that the other three names invite, because each of them is attached to a different landmark and, as printed here, to an impossible date. A.G. Tansley coined the term 'ecosystem', and he did so in 1935; he died in 1955, so no work of his can carry the date printed against his name in option (3). Ernst Haeckel coined the word 'ecology' — Oekologie — in 1866, and he died in 1919, so the date printed in option (4) cannot belong to him either, quite apart from the misspelling of his name. Neither Tansley nor Haeckel is associated with the biome in any case: one gave ecology the ecosystem and the other gave it its name. That leaves Clements, whose entire body of work was about vegetation units, succession and the climatic climax, and to whom the concept properly belongs.

• (1)McNaughton and Wolff (1932) — A pair of names with no standard claim to the coining of 'biome' in any history of ecology, and a date that attaches to no landmark in the naming of the concept. The option works as a distractor precisely because the names are unfamiliar: a candidate who does not recognise them may assume they belong to a specialist literature that he has simply not read, and prefer them over the familiar names for that reason. Unfamiliarity is not evidence, and in an attribution question the safer move is to eliminate the names whose actual contributions are known.
• (3)A.G. Tansley (1974) — Arthur G. Tansley's contribution is the ecosystem, a term he introduced in 1935 for the unit comprising organisms together with the whole complex of physical factors forming their environment. It is a different concept from the biome, defined on a different basis — functional interaction rather than regional vegetation type — and at a different scale. The printed date compounds the error: Tansley died in 1955, so 1974 cannot mark any work of his. This is the most attractive wrong option because Tansley is the name most strongly associated with foundational ecological concepts.
• (4)E.H. Heckel (1933) — Ernst Haeckel, whose name is misspelt here, gave ecology its name — he coined Oekologie in 1866 for the study of the relations of organisms to their environment. He was a nineteenth-century zoologist and morphologist and died in 1919, so the date of 1933 printed against him is impossible; nor did he propose any regional vegetation unit. A candidate who recognises Haeckel as a founding figure of ecology and stops there will be drawn to this option, when the correct association is with the discipline's name rather than with any of its later units.

A biome is a major regional ecological unit, defined by the dominant type of vegetation and by the animal life adapted to it, and controlled principally by climate — above all by the combination of temperature and precipitation. The same biome therefore recurs in widely separated parts of the world wherever the climate is similar: tropical rainforest in the Amazon, the Congo and Southeast Asia; savanna in East Africa, the Brazilian campos and northern Australia; Mediterranean scrub in California, Chile, the Cape and around the Mediterranean itself. Biomes sit in a hierarchy of ecological units that is worth keeping straight: the individual organism, the population, the community, the ecosystem, which adds the physical environment as a functioning whole, the biome as a regional grouping of similar ecosystems, and the biosphere as the sum of all of them. The biome is thus a vegetation-and-climate concept, while the ecosystem is a functional concept that can be applied at any scale — a pond, a field or a forest — which is why the two terms have different authors and different dates.

The vocabulary of ecology was built up over roughly seventy years by a small number of identifiable coinages, and examiners return to them because each is a single name attached to a single word and a single year. Ernst Haeckel named the discipline in 1866. Frederic Clements gave it the biome in 1916 and, in the same year, the theory of succession towards a single climatic climax — the monoclimax theory that dominated plant ecology for a generation and was later modified by polyclimax and climax-pattern views. Arthur Tansley introduced the ecosystem in 1935, explicitly as a corrective to what he considered the over-organismic language of the Clementsian school. Raymond Lindeman put numbers to energy transfer between trophic levels in 1942, and Eugene Odum's textbook of 1953 organised the whole field around the ecosystem. Later refinements of the biome concept — Leslie Holdridge's life zones of 1947 and Robert Whittaker's classification of biomes on axes of temperature and precipitation — are extensions of what Clements began.

• The term 'biome' is credited to Frederic E. Clements, who proposed it in 1916; the concept was developed with the animal ecologist Victor Shelford in their joint work Bio-Ecology in 1939, where the biome is treated as the combined plant and animal community of a major climatic region.
• Clements is also the author of the monoclimax theory of ecological succession, set out in Plant Succession in 1916, which held that succession in any region proceeds to a single climax community determined by the regional climate.
• Ernst Haeckel coined the word 'ecology' (Oekologie) in 1866 for the study of the relations of organisms to their surroundings. He was a zoologist and morphologist of the nineteenth century and died in 1919.
• A.G. Tansley coined the term 'ecosystem' in 1935, for the unit formed by organisms together with the whole complex of physical factors of their environment. He died in 1955, and the ecosystem is a functional unit applicable at any scale, unlike the biome, which is regional and climatic.
• Biomes are determined chiefly by temperature and precipitation, which is why the same biome type recurs in separated continents under similar climates. The principal terrestrial biomes are tropical rainforest, tropical savanna, desert, temperate grassland, temperate deciduous forest, Mediterranean scrub, boreal forest or taiga, and tundra.

• Confusing the biome with the ecosystem. The biome is a regional unit identified by dominant vegetation under a given climate; the ecosystem is a functional unit of organisms plus physical environment that can be as small as a pond. Different concepts, different authors, different years.
• Attaching the coining of 'ecology' to the wrong figure. Haeckel named the discipline in 1866; Clements and Tansley named units within it half a century later, and options in this topic routinely shuffle the three names against one another.
• Trusting an unfamiliar name in an attribution question because it sounds specialised. In a question of this shape the reliable method is to eliminate the names whose real contributions you know, rather than to gamble on the one you do not recognise.

Attribution questions — who coined a term, who proposed a theory, in what year — are a standing feature of the environment section, and they are answered by recall alone, so the preparation is a short table rather than an argument. Keep six lines: Haeckel and ecology in 1866, Clements and the biome in 1916, Tansley and the ecosystem in 1935, Lindeman and the ten per cent law in 1942, Odum and ecosystem ecology in 1953, and the Millennium Ecosystem Assessment of 2005 for ecosystem services. Note also that this paper prints dates against every name in the option set, some of them impossible for the person named; where a date is offered, it is a second thing to check, and an option whose date falls after the death of the scientist it names can be rejected without knowing anything else about it.

No directly related past PYQ was found.

• practice — not a real PYQ

  The term 'ecology' was coined in 1866 by which scientist ?

  • (a)Frederic Clements
  • (b)Ernst Haeckel
  • (c)A.G. Tansley
  • (d)Eugene Odum

  Answer(b) Ernst Haeckel — he coined Oekologie in 1866 for the study of the relations of organisms to their environment, giving the discipline its name. Clements proposed the biome in 1916, Tansley the ecosystem in 1935, and Odum's 1953 textbook organised modern ecology around the ecosystem concept without originating any of these terms.

• practice — not a real PYQ

  The global distribution of terrestrial biomes is determined principally by :

  • (a)Soil type and parent rock
  • (b)Temperature and precipitation
  • (c)Altitude alone
  • (d)Latitude alone

  Answer(b) Temperature and precipitation — the two climatic variables on which biome classifications are built, which is why the same biome recurs on separated continents wherever the climate is similar, as with Mediterranean scrub in California, Chile, the Cape and the Mediterranean basin. Soil, altitude and latitude all influence vegetation, but they operate through their effect on temperature and moisture.