Ecological Concepts: Biotic, Abiotic Factors, and Trophic Dynamics

Fundamental Ecological Definitions

Ecosystem

An Ecosystem is a particular area where environmental conditions allow the development of specific entities.

Biotope

The Biotope is the physical environment in which an ecosystem is established.

Biocenosis

The Biocenosis is the set of living beings that inhabit the biotope.

Abiotic Factors

Abiotic factors are all the non-living environmental factors of an ecosystem.

Classification of Abiotic Factors

• Aquatic Factors: Light, salinity, and pressure.
• Terrestrial Factors: Soil type, temperature, humidity, and lighting.

Specific Abiotic Components

• Climatic Factors: These are the most important factors for any organism's growth, including temperature and precipitation.
• Physical and Chemical Factors:
  • Light: A crucial factor for the distribution of organisms that perform photosynthesis (e.g., algae).
  • Oxygen: Present in the air, but its dissolved amount decreases in water, where aquatic organisms take it in.
  • Soil: Soil characteristics are very important because they determine the development of vegetation.

Trophic Relationships and Energy Flow

Trophic relationships describe how energy and nutrients move through the ecosystem.

Producers (Autotrophs)

Producers are living beings capable of synthesizing organic matter from inorganic matter. Examples include plants and algae.

Consumers (Heterotrophs)

Heterotrophic beings must obtain organic matter from other sources (what producers create). They are called Consumers, including bacteria, protozoa, animals, and fungi.

Consumer Classification

• Primary Consumers (Herbivores): Feed directly on producers (e.g., rabbits, deer).
• Secondary Consumers (Carnivores): Feed on primary consumers (e.g., foxes, badgers).
• Tertiary Consumers (Apex Predators): Feed on secondary consumers (e.g., wolves, eagles).

Decomposers

Decomposers feed on remnants of organic matter (e.g., bacteria and fungi). Decomposers are critical in an ecosystem because they break down organic matter and transform it into inorganic matter, allowing the latter to be reused by producers.

Biotic Factors: Species Interactions

Biotic factors are the relationships established between living beings in an ecosystem (e.g., feeding, defending themselves from predators, reproducing, moving).

Intraspecific Relationships (Same Species)

Relationships established between individuals of the same species:

• Family: Groups consisting of one or both parents and offspring, often formed to feed and protect the weak.
• Gregarious: Associations of organisms moving together (e.g., flocks of birds).
• Colonial: Organisms that live closely together (e.g., corals and sponges).
• Social: Relationships that establish a hierarchy and a distribution of tasks. These are typical of insects such as bees or wasps.

Interspecific Relationships (Different Species)

Relationships established between individuals of different species:

• Competition: Occurs when two organisms compete for the same resource (e.g., light, space, food).
• Predation: When one organism, the predator, kills another, the prey, to feed itself.
• Symbiosis: A permanent relationship between individuals of different species, which often results in a mutual benefit:
  • Mutualism: A relationship in which both species benefit (e.g., the alga produces organic matter, while the fungus allows fixing to the substrate).
  • Commensalism: An association in which one species benefits, but the other neither benefits nor is harmed (e.g., the clownfish and anemones).
  • Parasitism: One species is harmed, but the other benefits (e.g., ticks).