Explore the concept of ecosystems, including the components of biotic and abiotic factors, the different types of ecosystems (terrestrial, aquatic, etc.), and the interactions between living organisms and their environment.
Introduction to Ecosystems
Key concepts, components, and processes
| Definition | A community of living organisms (plants, animals, microbes) interacting with each other and with their non‑living (abiotic) environment, forming a functional unit. |
|---|---|
| Scope | Can be as small as a puddle or as large as a biome (e.g., a rainforest). |
| Main Idea | Energy flows through the system while matter cycles within it. |
| Component | Description | Examples |
|---|---|---|
| Biotic (living) | All organisms that occupy the ecosystem. | Producers (grass), consumers (deer), decomposers (fungi) |
| Abiotic (non‑living) | Physical and chemical factors that influence life. | Sunlight, temperature, water, soil, minerals, atmospheric gases |
| Habitat | The physical place where a species lives. | Forest canopy, riverbed, coral reef |
| Niche | The role an organism plays (its “job”) – how it obtains energy, reproduces, interacts. | Pollinator (bee), top predator (wolf) |
Visual cue: Energy pyramid – broad base (plankton) → narrow tip (apex predator).
| Cycle | Core Process | Key Participants |
|---|---|---|
| Carbon Cycle | Photosynthesis (CO₂ → organic C) ↔ Respiration, decomposition (organic C → CO₂) | Plants, animals, microbes, oceans |
| Nitrogen Cycle | Nitrogen fixation → Nitrification → Assimilation → Ammonification → Denitrification | Legume bacteria, nitrifying bacteria, fungi, plants |
| Water (Hydrologic) Cycle | Evaporation → Condensation → Precipitation → Runoff → Infiltration | All organisms (transpiration), atmosphere, soils |
| Phosphorus Cycle | Weathering → Uptake → Decomposition → Sedimentation | Plants, animals, soils, sediments (no atmospheric phase) |
Important: Matter is recycled, not lost; energy is flowing and eventually dissipates as heat.
| Category | Scale | Typical Characteristics |
|---|---|---|
| Terrestrial | Land‑based | Forests, grasslands, deserts, tundra |
| Aquatic | Water‑based | Freshwater (lakes, rivers), marine (oceans, coral reefs) |
| Artificial / Managed | Human‑influenced | Agricultural fields, urban parks, reservoirs |
| Micro‑ecosystems | Very small | Pond micro‑habitat, leaf |