Introduction to Ecology

Study Notes

Coined in 1866 by German biologist Ernst Haeckel from Greek words "Oikos" (home) and "Logos" (study).
Defined as the study of relationships between organisms in their natural habitats and their interactions with surroundings.

Introduced by British ecologist Arthur Tansley in 1935.
The basic structural and functional unit of ecology, comprising biotic communities interacting with a non-living environment.
Examples include grassland, forest, and aquatic ecosystems.

Natural Ecosystems:
- Aquatic: Freshwater (running and standing), marine.
- Terrestrial: Grassland, forest, desert.
Artificial/Engineered Ecosystems: Created or modified by human activities.

Biotic Components:
- Producers: Photo-autotrophs and chemo-autotrophs (e.g., Nitrosomonas, iron bacteria).
- Consumers: Herbivores, carnivores, omnivores, and detritivores.
- Decomposers: Organisms that break down organic matter.
Abiotic Components:
- Physical: Climate (sunlight, temperature, humidity, rainfall, wind), soil characteristics (type, moisture, pH), geographic conditions (latitude, longitude, altitude).
- Chemical: Nutrients (macro/micro), trace elements, pollutants.

Food Chain: Linkage of organisms for food energy transfer.
- Grazing Food Chain: Energy starts with plants.
- Detritus Food Chain: Energy starts with decomposed organic matter.
Food Web: Interconnected food chains demonstrating energy flow.
Trophic Levels: Steps in a food chain where food/energy transfer occurs.

Visual representation of energy and biomass distribution across trophic levels.
Base of the pyramid consists of producers; successively higher levels contain consumers.
Types of Ecological Pyramids:
- Pyramid of Numbers: Represents population numbers at each trophic level.
- Pyramid of Biomass: Depicts weight of organisms rather than number.
- Pyramid of Energy: Illustrates energy flow; typically upright in shape.