Aartee Mishra is teaching live on Unacademy Plus
Environment Book Summary Presented B Aartee Mishra
CHAPTER 2 FUNCTIONS OF AN ECOSYSTEM (Part-1)
THE FUNCTION OF AN ECOSYSTEM . The function of an ecosystem is abroad, vast and complete dynamic system. It can be studied under the following three heads. 1. Energy flow 2. Nutrient cycling (biogeochemical cycles) 3. Ecological succession or ecosystem development ENERGY FLOW Energy is the basic force responsible for all metabolic activities. The flow of energy from producer to top consumers is called energy flow which is unidirectional. The study of Trophic level interaction in an ecosystem gives an idea about the energy flow through the ecosystem.
Trophic interaction deals with how theTrophic levels (Trophe - nourishment) members of an ecosystem are connected based on nutritional needs. 1 |Autotrophs | Green plants (producers) I Heterotophs Herbivore . This energy always flows (primary consumers) from lower (producer) to , | Heterotrophs | Carnivores higher (herbivore, carnivore i etc.) trophic level. (secondary consumers) Carnivore Heterotophs (tertiary consumers) lop carnivores V | Heterotrophs!Ouartermary consumers)
. There is a loss of some energy in the form of unusable heat at each trophic level so that energy level decreases from the first trophic level upwards There are usually four or Five trophic levels and seldom more than six as beyond that very little energy is left to support. any organism. Trophic levels are numbered according to the steps an organism is away from the source of food or energy, that is the producer. The trophic level interaction involves three concepts namely:- 1. Food Chain 2. Food Web 3. Ecological Pyramids
FOOD CHAIN Organisms in the ecosystem are related to each other through feeding mechanism or trophic levels, i.e. one organism becomes food for the other. A sequence of organisms that feed on one another, form a food chain. Grazing Food Chain Food Chain Types of Food Chains In nature, two main types of food Prim ry chains have been distinguished: Producer Consumer Secondary Consumer Tertiary Consumer Grazing food chain . The consumers which start the food chain, utilising the plant or plant part as their food, constitute the grazing food chain. Decomposers