Overview
This lecture reviews the definitions and relationships among populations, communities, ecosystems, and biomes, and explains how ecosystems are classified and structured.
Populations and Communities
- A population is all members of the same species in a specific area.
- Multiple populations of different species in the same area form a community.
- Communities consist only of living (biotic) factors.
Ecosystems
- An ecosystem includes all living (biotic) and non-living (abiotic) factors in a given area.
- Abiotic factors are non-living components such as water, rocks, and climate.
- Ecosystems can be defined on various scales, from small tide pools to entire rainforests.
- Both terrestrial (land) and aquatic (water-based) ecosystems exist.
Types and Classification of Ecosystems
- Aquatic ecosystems can be divided into marine (saltwater) and freshwater types.
- Marine ecosystems include oceans and salty or partially salty environments.
- Freshwater ecosystems include rivers and lakes and make up a small subset of all aquatic ecosystems.
- Even small environments, such as a section of skin, can be considered ecosystems due to their biotic and abiotic interactions.
Biomes
- Biomes are major types of land ecosystems, classified by climate and geography.
- Examples include tropical forests, boreal forests, savannah, desert, tundra, chaparral, polar regions, temperate forests, and temperate grasslands.
- Environmental factors like temperature, moisture, terrain, and minerals help determine the biome.
- Similar biomes in different locations can vary in their abiotic and biotic factors.
Key Terms & Definitions
- Population — all individuals of the same species in a specific area.
- Community — all the populations of different species in the same area.
- Biotic factors — living components in an environment.
- Abiotic factors — non-living components like rocks, water, and climate.
- Ecosystem — a system including both biotic and abiotic factors in a specific area.
- Biome — a large region classified by its climate, terrain, and types of organisms present.
- Marine ecosystem — aquatic ecosystem in salty or partially salty water.
- Freshwater ecosystem — aquatic ecosystem in non-salty water.
Action Items / Next Steps
- Review diagrams of major biomes and their locations.
- Be able to define and distinguish populations, communities, ecosystems, and biomes.