Ecosystems: Concepts, Function, and Types

Fundamental Ecological Concepts

Key Ecological Definitions

• Biosphere: The set of all creatures that inhabit the Earth.
• Microorganisms: Bacteria or protozoa.
• Ecosystem: All living beings that inhabit a particular place, interacting with their environment.
• The Ecosphere: The set of all ecosystems on our planet.
• Ecosystems: Composed of biocoenosis and biotope.
• Biocoenosis: The living community within an ecosystem.
• Biotope: The inorganic part of an ecosystem.
• Habitat: The physical location within an ecosystem where individuals of a particular species live.
• Ecological Niche: The role of a species in the ecosystem. It is defined by behavior, the type of food consumed, where food is sought, etc.

Abiotic Factors in Ecosystems

These are the non-living components of the environment.

• Abiotic Factors (Aquatic): Salinity, pressure, water movement, light.
• Abiotic Factors (Land): Temperature, light, and moisture.

Ecosystem Function: Matter and Energy Flow

Matter and energy are transmitted through food (trophic) relationships that are established among organisms.

Trophic Relationships and Pyramids

Energy and biomass distribution can be represented by pyramids:

• Pyramids: Numbers, Biomass, Energy.

Trophic Roles: Producers, Consumers, Decomposers

• Producers: Organisms that fabricate their own organic material from inorganic substances (CO2, minerals), typically through photosynthesis. Producers form the base of the food chain.
• Consumers: Organisms with heterotrophic nutrition; they feed on other living beings.
• Decomposers: Organisms that convert organic matter (proteins, fats, carbohydrates) into inorganic substances (CO2, water, minerals) that dissolve in soil or water. These inorganic substances can then be reused by producers.

Through decomposition, organic matter is transformed into inorganic matter, which can be used again by producers.

Biotic Relationships in Ecosystems

These occur between living organisms.

• Intraspecific Relations: Occur between individuals of the same species.
• Interspecific Relations: Occur between organisms of different species.

Major Types of Ecosystems

Terrestrial Ecosystems

Human beings live on land, surrounded by air. Terrestrial ecosystems are less extensive than aquatic ones.

• Abiotic Factors in Terrestrial Environments: Temperature, light, humidity. Three zones are distinguished in each hemisphere: cold zone, temperate zone, and warm zone.
• Major Terrestrial Ecosystems: Cold desert, tundra, taiga, steppe, deciduous forest, Mediterranean forest, equatorial rainforest, savannah, hot desert.

Aquatic Ecosystems

Human beings are surrounded by water (this sentence seems out of place here, likely a remnant from a previous thought). Aquatic ecosystems include marine and freshwater types.

• Abiotic Factors in Aquatic Environments: Light, temperature, pressure, salinity, oxygen.
• Living Organisms in Water: Plankton, Nekton, Benthos.
• Marine Ecosystems: Classified by Depth (pelagic zone, bathyal, abyssal) and Distance from shore (neritic zone, open sea).
• Freshwater Ecosystems: Classified as running water (rivers, streams) or stagnant waters (lakes, ponds - coastal waters, open waters, depth zones).

Understanding Biodiversity

Biodiversity: A variable used in ecology to assess the quality of an ecosystem's biocoenosis and the number of different species that constitute it.