Published: Published Date – 11:20 PM, Sat – 7 May 22
Hyderabad: The study of life, living organisms, life cycles of various species of organisms, and the environments they live in – broadly speaking, these topics come under the biological sciences. From single cell organisms to well-developed species, from various plant species to aquatic life to terrestrial beings, everything living becomes part of the studies, which is categorized as biological sciences.
These series of articles will help you understand each of the topics under this category well, and answer questions in the TSPSC exam with confidence.
Ecosystem & their components:
An ecosystem is a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment, and it varies greatly in size — from a small pond to a large forest or a sea.
Many ecologists regard the entire biosphere as a global ecosystem and as a composite of all local ecosystems on earth. Since this system is too big and complex to be studied at one time, it is convenient to divide it into two basic categories — Natural Ecosystem and Artificial Ecosystem.
The Natural Ecosystems:
These are naturally occurring ecosystems and there is no role of humans in the formation of such type of ecosystems. These are categorized mainly into two types — Aquatic Ecosystems and Terrestrial
While Aquatic Ecosystems are based on the salinity of water, three types of aquatic ecosystems are identified — Marine, Estuarine and Fresh Water Ecosystem.
Marine Ecosystem: The Marine Ecosystem is the largest of all the aquatic ecosystems and is the most stable one.
Estuarine Ecosystem: Estuary is the area where river joins the sea. The sea water ascends up into the river twice a day (effect of high tides and low tides). The salinity of water in an estuary also depends on the seasons and during the rainy season outflow of river water makes the estuary less saline while the opposite occurs during the summer. Estuarine organisms are capable of withstanding the fluctuations in salinity.
Fresh Water Ecosystems: The Fresh Water Ecosystem is the smallest aquatic ecosystem and it includes rivers, lakes, ponds, etc. It is further divided into two groups—Lentic Ecosystems and Lotic Ecosystems.
The still water bodies like ponds, lakes, reservoirs, etc., fall under the category of Lentic Ecosystems whereas streams, rivers and flowering water bodies are called Lotic Ecosystems. The study of Freshwater Ecosystem is called Limnology.
Lake Ecosystem: To understand the fundamentals of an aquatic ecosystem, let us take a lake as an example. This is fairly a self-sustainable unit and a simple example that explains even the complex interactions that exist in an aquatic ecosystem.
They are deeper than ponds (pond is not an ideal example as it is very shallow) and most lakes contain water throughout the year. In deep lakes, light cannot penetrate more than 200 meters, in depth. They are vertically stratified in relation to light intensity, temperature, pressure, etc.
Deep water lakes contain three distinct zones namely — Littoral zone, Limnetic zone and Profundal zone.
To be continued…
Dr. Modala Mallesh
Palem, Nakrekal, Nalgonda