Definitions [1]
Define a consumer.
A consumer is an organism that obtains energy by feeding on other organisms. As it cannot produce its own food, consumers rely on plants or other animals for nourishment, which are a vital part of the food chain. Consumers are further classified into primary consumers, secondary consumers, and tertiary consumers.
Key Points
Key Points: Concept of Ecosystem
- An ecosystem is a self-regulating and self-sustaining unit of nature that includes both living (biotic) and non-living (abiotic) components interacting with each other.
- The term ecosystem was given by A.G. Tansley in 1935, and ecosystems can vary in size from a small pond to the entire biosphere.
- Ecosystems are mainly of two types: terrestrial (forest, grassland, desert) and aquatic (lakes, rivers, oceans), and can also be natural or artificial.
- Producers, consumers, and decomposers are the main biotic components; producers make food, consumers depend on them, and decomposers break down waste and recycle nutrients.
- All organisms, including small or unnoticed ones like insects and microbes, play an important role in maintaining balance and cleanliness in the ecosystem.
Key Points: Structure and Function of an Ecosystem
- Two Structural Features → Species Composition (identifying species) + Spatial Pattern (distribution of biotic/abiotic components).
- Two Spatial Patterns → Stratification (vertical, e.g., trees→shrubs→herbs) + Zonation (horizontal, e.g., inter-tidal, littoral zones).
- Types → Terrestrial (forest, grassland, desert) + Aquatic (lakes, rivers, seas, oceans).
- Classification → Natural (self-sustainable) + Artificial (needs human input, e.g., farmland, fish tank).
- Components → Biotic (living) + Abiotic (non-living).
- 4 Functions → Productivity + Decomposition + Energy Flow + Nutrient Cycling (PDEN).
