STD VIII – ECOSYSTEMS (Hybrid)

Introduction:

An ecosystem is a structural, functional and life-sustaining environmental system. The more complex the structure the greater is the diversity of the species in the ecosystem.

 From the structure point of view, all ecosystems consist of two basic components: Biotic and Abiotic.

In this chapter, we will study about ecosystem and components in detail.

Ecosystem – An ecosystem is a community of plants, animals and smaller organisms that live, feed, reproduce and interact in the same area or environment. It comprises of both biotic (living) and Abiotic (non-living) components

An Ecosystem consists of two main components:

Biotic Component

Abiotic Component

Food Chains, Food Web and Food Pyramids

One of the earliest descriptions of a food chain was by a medieval Afro-Arab  scholar named Al Jahiz: “All animals, in short, cannot exist without food, neither can the hunting animal escape being hunted in his turn.”

Charles Elton subsequently pioneered the concept of food cycles, food chains, and food size in his classical 1927 book “Animal Ecology”; Elton’s ‘food cycle’ was replaced by ‘food web’ in a subsequent ecological text.The notion of a food web was also mentioned in the writings of Charles Darwin.

Abiotic Factors:

Temperature | Sunlight | Humidity | Wind | Soil | Air | Water

Biotic Components

Producers | Herbivores | Carnivores | Decomposers | Parasites