Ecosystems: Definition, Concept

Definition and Concept of Ecosystems: Ecology is the scientific study of the relationships between living organisms and their physical environment, as well as their interactions with one another. Ecology can be approached from two main perspectives:

1. The environment and the demands it places on organisms.
2. Organisms and their adaptations to environmental conditions.

An ecosystem is a community of mutually interacting organisms and their environment, where the exchange of materials occurs in a largely cyclical manner. It consists of physical, chemical, and biological components, along with energy sources and pathways for energy and material exchange.

• The environment in which a particular organism lives is called its habitat.
• The role of an organism within its habitat is termed its niche.

For ecological studies, the environment is often categorized into four broad types:

1. Terrestrial Environment – Land-based ecosystems, including biomes such as grasslands, forests, savannas, and deserts.
2. Freshwater Environment – Includes standing-water habitats (e.g., lakes, reservoirs) and running-water habitats (e.g., streams, rivers).
3. Oceanic Marine Environment – Characterized by saltwater, with the neritic zone covering the shallow waters of the continental shelf.
4. Oceanic Region – Comprises the deeper waters of the ocean beyond the continental shelf.

Subdivisions of Ecology: Modern ecology is broadly divided into two major approaches:

1. Ecosystem Ecology – Studies ecosystems as large functional units.
2. Population Ecology – Examines ecosystem behavior based on the properties of individual species populations.

In practice, these two approaches are often integrated.

• Descriptive Ecology focuses on describing the types, structures, and distributions of organisms within ecosystems.
• Functional Ecology investigates how ecosystems operate, including population responses to environmental changes and energy and material flow within ecosystems.

Types of Ecosystems: Ecosystems are categorized into two broad types:

1. Natural Ecosystems – These exist naturally without human intervention and are further classified as:
   • Terrestrial Ecosystems: Includes hot deserts, grasslands, tropical and temperate rainforests.
   • Aquatic Ecosystems: Includes ponds, rivers, streams, lakes, estuaries, oceans, mangroves, swamps, and bays.

These natural ecosystems are self-regulating, open systems with continuous input and output exchanges with surrounding systems.

2. Artificial Ecosystems – These are human-made, relatively simple, unstable, and subject to human intervention and manipulation. They are often created by clearing natural ecosystems, such as:
   • Crop fields
   • Agricultural lands

Artificial ecosystems require human management to maintain stability, unlike self-sustaining natural ecosystems.

Understanding ecosystems is fundamental to conservation, resource management, and sustainable development, ensuring a balanced relationship between humans and nature.