Lecture1_ Introduction to Ecology

Introduction to Ecology

• Definition: Scientific study of interactions among organisms and their environment.

Types of Interactions

• Predator-prey: Dynamics where one organism consumes another.

• Food source: Organisms provide energy through food chains.

• Competition: Struggle for limited resources (food, shelter, mates).

• Symbiosis: Interactions between species living together, benefiting one or both.

• Shelter: Organisms interact with their environment for safe habitats.

Biosphere and Ecological Hierarchy

Levels of Organization

• Biosphere: All ecosystems on Earth, includes land, water, and atmosphere.

• Ecosystem: Community of organisms interacting with their physical environment.

• Community: Different populations living together in a defined area.

• Population: Group of organisms of the same species in a given area.

• Organism: Individual living entity.

Characteristics of Living and Non-Living Things

• Examples:

  • Biosphere: Contains all ecosystems (e.g., grasslands, forests, oceans).

  • Ecosystem: Interactions between biotic (living) and abiotic (non-living) factors.

  • Community: Involves interactions between various organisms (e.g., hawks, snakes, bison).

  • Population: Specific group of organisms (e.g., bison herd).

  • Organism: E.g., a single bison.

• Cell: Smallest functional unit of life.

Ecosystems

• Definition: A community of living organisms interacting with their physical environment.

• Influenced by both biotic and abiotic factors.

Biotic vs. Abiotic Factors

• Biotic Factors: All living components that influence ecosystems (e.g., interactions among populations).

• Abiotic Factors: Physical, non-living components (e.g., light, temperature, soil type).

Types of Ecosystems

• Terrestrial Ecosystems: Includes deserts, tundras, forests.

• Aquatic Ecosystems: Encompasses freshwater and marine environments (e.g., ponds, coral reefs).

The Niche

• Definition: The role and position a species holds in its ecosystem.

  • Includes how it meets food and shelter needs, survival strategies, and contributions to ecosystem dynamics.

Examples of Ecological Niches

• Avocets: Feed on insects, utilizing unique bill adaptations.

• Oystercatchers: Open bivalve shells with specialized bills.

• Plovers: Hunt for small invertebrates across diverse habitats.

• Flamingos: Filter food from mud using powerful tongues.

• Dabbling Ducks: Feed on aquatic plants and insects by flipping their bodies.

Importance of Unique Niches

• Unique niches reduce competition for limited resources, allowing coexistence without direct competition for food and habitat.