Lecture: Ecosystems and Biomes

Key Concepts and Definitions

Population

• Definition: Members of a species sharing the same area.
• Members in different areas are not part of the same population.
• Multiple populations of different species can inhabit the same area.

Community

• Definition: All populations in a given area (only living things, i.e., biotic factors).
• Biotic factors = living things in an area.

Ecosystem

• Definition: Includes all biotic (living) and abiotic (non-living) factors in a region.
• Examples of abiotic factors: water, rocks, air.
• Scale can vary from very small (e.g., tide pool) to very large (e.g., Amazon rainforest).
• Matter and energy flow through ecosystems (e.g., energy from light transfers through organisms and becomes heat).

Types of Ecosystems

• Can be classified broadly as terrestrial (land-based) or aquatic (water-based).

Aquatic Ecosystems

• Marine: Saltwater ecosystems (e.g., oceans).
• Freshwater: Non-salty water ecosystems (e.g., rivers, lakes).

Terrestrial Ecosystems (Biomes)

• Biomes: Major types of land ecosystems.
  • Tropical Forest: Found in Amazon, Africa, Southeast Asia, Central and Southern North America.
  • Boreal Forest
  • Savannah
  • Desert: (e.g., Sonoran Desert in the US/Mexico, Rock Desert on the island of Boa Vista).
  • Tundra
  • Chaparrel
  • Polar Ice
  • Temperate Forest
  • Temperate Grasslands

Factors Determining Biomes

• Climate (temperature and moisture)
• Terrain
• Minerals in the region

Specific Examples

• Tide Pools: e.g., at Half Moon Bay, includes both biotic (starfish, anemones) and abiotic (water, rocks) factors.
• Rainforest: Amazon rainforest as an example of a large ecosystem.
• Deserts: Comparison between Sonoran Desert and Rock Desert highlighting differences despite being the same biome category.

Unique Ecosystems

• Even small areas such as sections of human skin can be considered ecosystems (microorganisms interacting with skin cells, oils, dead skin).