Ecology and Environment Notes Part 1 – Ecosystem

Ecology is a distribution and abundance of living organisms and their relationship with the environment. It is a branch of biological science. There are four basic concepts of ecology which are as follows:

  • Holism: is a philosophy term which conceived as a directive and creative principle operating from initial to the last level in ecology.
  • Ecosystem: involve both the living and non-living factors working together, working in a complex web.
  • Succession: the living organisms and its environment commonly reactive and influence each other in different ways. Increase in the capacity of tolerance towards changing the environment by modifying their environment as the process of growth, dispersal, reproduction, death and decay follows changing the abiotic component of the ecosystem is called a succession.
  • Conservation: Regulation of the population through naturally operating tropism ensures the resilience of the system.

Realm of Ecology

Ecology as a basic division of biology explains patterns within and among organism. The hierarchical level of ecology is shown below.

  • Biosphere
  • Ecosystem
  • Communities
  • Population
  • Organism


The global conglomeration of all the ecosystem i.e. a zone where all the living organisms on earth together with the dead organic matter produced by them exist. It is the key component of earth systems, intermingle with and exchange matter and energy with the other spheres, helping to drive the global biogeochemical cycling of carbon, nitrogen, phosphorus, sulfur and other elements. It includes the lithosphere, hydrosphere, atmosphere and other “spheres” (e.g. cryosphere, anthrosphere, etc.).


The ecosystem is defined as a specific and recognizable landscape such as such as forest, wetland, coastal area, grasslands, deserts etc having both living and nonliving elements

Components of Ecosystem

  • Abiotic components are the nonliving elements of an ecosystem as air, water, climate and soil etc containing both organic and inorganic matters.
  • Biotic components consist of all the living community of plants and animals in an area together with the non-living components of the environment such as soil, air and water.

Function of Ecosystem

The function of the ecosystem can be referred a producer-consumer arrangement of nutrients known as energy cycles and each food level of this pyramid is known as a trophic level. The three major aspects of energy cycles are food chain, food web and ecological pyramids. The food chain is a chain or series of feeding relationship among different living things in a particular environment or habitat. The plant is always the first step of the food chain as it produces its own food from non-living things and eventually eaten by the next higher level of living orgasm such as herbivores who only takes plant as their food item. The plants are the known as producers and the animal depend upon producers are known as a primary consumer. The next level in this hierarchy is known as a secondary consumer who depends on the primary consumer for food.


Food Web is defined as the system of interlocking and interdependent food chains.


Energy Pyramid is a graphical presentation of the trophic levels in an ecosystem where the energy from the sun is transferred through the ecosystem by passing through various trophic levels. Only 10% of energy gets transferred from one trophic level to the next.



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