Understanding Ecosystems: Biotope, Biocenosis, and Dynamics

Ecosystems: An Overview

Ecology is the science that studies the characteristics of living beings, their environment, and the relationships they build with each other and their surroundings.

What is an Ecosystem?

An ecosystem consists of a fragment of the biosphere where living organisms interact and form relationships.

Biotope

The biotope is the physical environment or place where living things develop, including the environmental conditions that characterize it.

Biocenosis

Biocenosis refers to the set of living organisms within a given ecosystem.

The Biotope: Terrestrial and Aquatic Environments

The terrestrial environment is located on the surface of the continents, while the aquatic environment is made up of water.

Abiotic Factors

Abiotic factors are the physical and chemical conditions of the biotope. These include:

• Light: The main source of energy in almost all ecosystems.
• Water: Essential for life; all organisms depend on it for survival.
• Temperature: Mean and variance determine the type of organisms inhabiting an ecosystem.
• Gases: Found in the atmosphere or dissolved in the hydrosphere, used by living organisms for vital functions.
• Soil Composition: Determines nutrient availability and water retention.
• Geographical Situation: Includes altitude, depth, sun exposure, slope, and prevailing winds and currents.

Biocenosis: Interspecific Relationships

Interspecific relationships within the biocenosis include:

• Predation: A predator species catches another (prey) for food.
• Parasitism: A parasite lives at the expense of a host, causing harm.
• Symbiosis: A mutually beneficial relationship between two organisms (symbionts).

Fluctuations in Populations

Fluctuations are variations in the number of individuals in a population over time. These can be due to:

• Environmental Changes: Accidental (e.g., drought) or cyclic (e.g., seasonal changes).
• Migrations: Movement of individuals due to changes in habitat conditions.
• Disproportion Between Predator and Prey: Causes significant changes in populations.

Ecosystem Dynamics

Trophic relationships are the relationships related to nutrition processes.

• Producers: Autotrophs that produce their own food.
• Consumers: Heterotrophic organisms that feed on organic matter from other living things.
• Decomposers: Heterotrophic organisms that feed on organic matter from the remains of living organisms.

Trophic Chains and Food Webs

Trophic chains are linear representations of organisms in an ecosystem that feed on each other. Food webs represent interconnected food chains within an ecosystem.

Matter and Energy in Ecosystems

Matter and energy are transferred between organisms through trophic relationships.

• The Cycle of Matter: The movement of matter along trophic levels, returning to the environment for reuse.
• The Energy Flow: The circulation of energy from producers to higher trophic levels, with gradual release into the environment.
• Biomass: The total mass of living beings. The biomass of each trophic level can represent the trophic pyramid of an ecosystem.

The trophic pyramid is made up of different levels, with producers at the base and consumers at higher levels.