The correct answer is: D. Charles Elton
Charles Elton was a British ecologist who first proposed the concept of ecological pyramids in his 1927 book “Animal Ecology”. He defined an ecological pyramid as a graphical representation of the number of individuals, biomass, or energy at each trophic level in a food chain.
Ecological pyramids are important because they help us to understand the flow of energy through an ecosystem. They can also be used to assess the health of an ecosystem by comparing the relative sizes of the different trophic levels.
Option A: E.P. Odum was an American ecologist who made significant contributions to the field of ecosystem ecology. He did not, however, propose the concept of ecological pyramids.
Option B: A.G. Tansley was a British ecologist who coined the term “ecosystem”. He did not, however, propose the concept of ecological pyramids.
Option C: Juday was an American ecologist who studied the food webs of freshwater ecosystems. He did not, however, propose the concept of ecological pyramids.