Concept:Ecological pyramidsA graphical representation of the biomass or bio productivity at each trophic level in a particular ecosystem is known as an ecological pyramid.The base of a pyramid is broad and it narrows towards the apex.This, relationship is expressed in terms of number, biomass or energy. The base of each pyramid represents the producers or the first trophic level while the apex represents the tertiary or top-level consumers.The three types of ecological pyramids that are usually studied are (a) pyramid of number; (b) pyramid of biomass and (c) pyramid of energy.?Explanation:ProducerThe green plant in the ecosystem is called producers.In a terrestrial ecosystem, major producers are herbaceous and woody plants.ConsumerAll animals depend on plants (directly or indirectly) for their food needs.They are hence called consumers.Pyramid of number?Food webs are a valuable tool for visualising the feeding interactions among creatures in a population, but they are not quantitative.In this process, smaller organisms are many, while larger organisms are few.In the pyramid of numbers, there is an inverse-size metabolic rate.Ecological pyramids in a thousand square meters of grassland.Producer ? Primary consumer ? Secondary consumer ? Territory consumer.In this pyramid level, 1 belongs to the producer (tree, grass),Level 2 belongs to the primary consumer (grasshopper, insect),Level 3 belongs to the secondary consumer (frog, spiders), Level 4 belongs to the terrestrial consumer carnivorous (snake).Hence, the frog occupies level 3 in these ecological pyramids.