MPSC 2021 Prelims Paper-I · Question 34 of 100

Correct — option (4), Odum. The definition quoted in the stem is the ecosystem-centred one, and it is credited to Eugene P. Odum, the American ecologist who did more than anyone else to make the ecosystem the working unit of the subject. Odum's Fundamentals of Ecology, written with his brother Howard T. Odum and first published in 1953, was for about ten years the only textbook in the field, and it organised the whole discipline around energy flow, nutrient cycling and the structure and function of ecosystems rather than around the description of communities. That is the intellectual move the quoted sentence records: ecology stops being the study of organisms in their surroundings and becomes the study of a system with parts, processes and measurable throughput. The year 1969 that the stem attaches to the definition is also the year of Odum's best-known paper, 'The Strategy of Ecosystem Development', published in Science, in which he set out how the structure and function of an ecosystem change as it moves through succession towards maturity. Note how the three other names in the option list are chosen: each of them is a real ecologist with a real and widely quoted definition of ecology, but not one of those definitions is framed on the ecosystem. Andrewartha and Krebs both define the subject through the distribution and abundance of organisms, and Taylor through the relations of organisms to their environments. The word that decides this question is 'ecosystem', and Odum is the name attached to it. The English stem is printed with broken grammar — '... who defined in 1969 ?' — which is the paper's own.

• (1)Krebs — Charles J. Krebs is a real and very widely read ecologist, but his definition of the subject is framed on populations rather than on ecosystems. His textbook is called Ecology: The Experimental Analysis of Distribution and Abundance, and the phrase in that title is the phrase in his definition: ecology is the scientific study of the interactions that determine the distribution and abundance of organisms. Krebs is known for helping to turn ecology from a descriptive into an experimental science, through the fence effect demonstrated in his vole enclosure experiment of 1965 and through a twenty-year study of snowshoe hare population cycles in the Yukon. Nothing in that programme is about the structure and function of ecosystems, which is Odum's language and not his.
• (2)Andrewartha — Herbert George Andrewartha, the Australian ecologist who lived from 1907 to 1992, defined ecology through the distribution and abundance of organisms, and his major book, written with L. C. Birch and published in 1954, is called The Distribution and Abundance of Animals. He is remembered as the most influential Australian ecologist and for arguing that density-independent factors such as weather matter more than density-dependent ones in regulating populations, a position he developed from studies of apple thrips and plague grasshoppers and restated in The Ecological Web of 1984. His subject is the population and its environment, not the ecosystem as a functioning unit, so the sentence quoted in the stem is not his.
• (3)Taylor — Taylor does have a definition of ecology and it is a famous one, but it is not the sentence quoted here. In a 1936 paper in the journal Ecology titled 'What is Ecology and What Good is It?', W. P. Taylor defined ecology as the science of all the relations of all organisms to all their environments — a deliberately all-embracing formulation that stresses the completeness of the relationships rather than any particular unit of study. The contrast with the stem is exactly the point: Taylor's definition names organisms and environments, while the quoted definition names the ecosystem and speaks of its structure and function. That vocabulary belongs to Odum. This option is the strongest of the three wrong ones for a candidate who recognises the name from a list of definitions without recalling which definition goes with it.

Ecology has been defined many times, and the definitions record the changing unit of study. Ernst Haeckel coined the word in the nineteenth century for the study of the relations of organisms to their surroundings. W. P. Taylor's 1936 formulation, the science of all the relations of all organisms to all their environments, is the broadest version of that tradition. Andrewartha, in 1954 and after, narrowed it to the distribution and abundance of animals, and Krebs later restated it as the study of the interactions that determine distribution and abundance — the population-ecology tradition, concerned with why there are as many of a species as there are and why they live where they do. Odum's contribution was different in kind. By making the ecosystem the unit — a community together with its physical environment, considered as a system through which energy flows and materials cycle — he gave ecology quantities it could measure: primary productivity, trophic levels, the ten per cent law of energy transfer, biogeochemical cycles, standing crop and succession towards a mature state. The definition in this question belongs to that programme, and so does his 1969 paper on the strategy of ecosystem development. The two traditions are complementary rather than rival, and a well-prepared candidate can name a representative definition from each.

Definitions and their authors are a standing item in the MPSC environment and ecology section, and the Commission tests them as straight attribution: a sentence in quotation marks and four names. There is no way to reason to the answer from first principles, but there is a reliable way to reason from vocabulary, and it is the one this question rewards. Each classical definition uses a distinctive keyword — Taylor's is relations, Andrewartha's and Krebs's is distribution and abundance, Odum's is ecosystem, structure and function. A candidate who has attached one keyword to each name can answer any question of this form, including ones built on definitions they have never seen, because the keyword in the stem points to the tradition and the tradition points to the name. The same technique works for the other definition-and-author items this paper and its neighbours set. It is worth adding that the English stem here is ungrammatical as printed; the Marathi block asks the same thing, and the question being asked is plainly who framed the definition.

• Eugene P. Odum is regarded as the founder of ecosystem ecology; the definition of ecology as the study of the structure and function of the ecosystem is credited to him.
• Fundamentals of Ecology, written by Eugene Odum with his brother Howard T. Odum and first published in 1953, was the only textbook in the field for about ten years.
• Odum's 1969 paper in Science, 'The Strategy of Ecosystem Development', describes how the structure and function of an ecosystem change through succession towards maturity.
• W. P. Taylor defined ecology in 1936, in a paper in the journal Ecology titled 'What is Ecology and What Good is It?', as the science of all the relations of all organisms to all their environments.
• H. G. Andrewartha wrote The Distribution and Abundance of Animals with L. C. Birch in 1954 and stressed density-independent controls; Charles J. Krebs, author of Ecology: The Experimental Analysis of Distribution and Abundance, defines ecology through the interactions that determine distribution and abundance.

• Attaching the wrong definition to a real ecologist; all four names in this question are genuine and each has a quoted definition, so recognising the name is not enough
• Ignoring the keyword in the quoted sentence, which is what identifies the tradition — ecosystem and structure and function point to Odum, distribution and abundance to Andrewartha and Krebs
• Confusing Eugene Odum with his brother Howard T. Odum, who co-wrote Fundamentals of Ecology and worked on systems ecology and energetics
• Reading a definition question as though it required judgement about which definition is best; it asks only who framed the one quoted

Attribution questions of this kind recur in the ecology block of MPSC papers, usually as a quoted definition with four names, and occasionally reversed, with a name in the stem and four definitions among the options. The Commission also asks who coined a term — ecology, ecosystem, biosphere, biome — and which scientist is associated with a named concept such as the ten per cent law or the ecological pyramid. Preparation is a single sheet of about a dozen definitions and coinages with their authors and years, each marked with the keyword that identifies it. Learn the keyword rather than the whole sentence, because the wording of a definition varies between textbooks while the keyword does not, and the keyword is what a question preserves.

No directly related past PYQ was found.

• practice — not a real PYQ

  Who is credited with the definition of ecology as the study of the structure and function of the ecosystem, and is regarded as the founder of ecosystem ecology?

  • (a)Ernst Haeckel
  • (b)H. G. Andrewartha
  • (c)Eugene P. Odum
  • (d)Charles J. Krebs

  Answer(c) Eugene P. Odum — his Fundamentals of Ecology, written with his brother Howard T. Odum and first published in 1953, was the only textbook in the field for about a decade and organised ecology around the ecosystem, its energy flow and its nutrient cycles. Haeckel coined the word ecology in the nineteenth century, while Andrewartha and Krebs both define the subject through the distribution and abundance of organisms.

• practice — not a real PYQ

  The definition of ecology as "the science of all the relations of all organisms to all their environments" was given in 1936 by

  • (a)W. P. Taylor
  • (b)Eugene Odum
  • (c)L. C. Birch
  • (d)Charles Elton

  Answer(a) W. P. Taylor — the definition comes from his 1936 paper in the journal Ecology titled 'What is Ecology and What Good is It?', and its distinguishing feature is the repeated word 'all', which makes the definition deliberately all-embracing. Odum's definition is framed on the structure and function of the ecosystem, L. C. Birch co-wrote The Distribution and Abundance of Animals with Andrewartha, and Charles Elton is associated with food chains, the ecological niche and invasion ecology.