Ecosystem Dynamics: Trophic Levels, Food Chains, and Energy Flow

Trophic Levels

A trophic level consists of all organisms within an ecosystem that share the same feeding strategy.

Producers

Producers are autotrophic organisms that perform photosynthesis, using solar energy to convert inorganic matter into organic matter.

Consumers

Consumers are heterotrophic organisms that obtain energy by consuming other living organisms.

Primary Consumers

Primary consumers are herbivores that feed directly on producers.

Secondary Consumers

Secondary consumers are carnivores that feed on primary consumers.

Tertiary Consumers

Tertiary consumers (supercarnivores) are carnivores that feed on secondary consumers, such as lions.

Decomposers

Decomposers are heterotrophic organisms that break down dead organisms and waste products, returning essential nutrients to the environment.

Trophic Relationships

Food Chains

A food chain is a diagram that illustrates the feeding relationships between organisms at different trophic levels within an ecosystem, using arrows and drawings or names.

Food Webs

Food webs are complex representations of interconnected food chains within an ecosystem, showing the flow of energy and nutrients.

Transfer of Matter and Energy

Organic Matter Creation

Producers create organic matter from inorganic substances, using it to build and repair their bodies.

Organic Matter Transfer

Organic matter from producers is transferred to primary consumers when they are eaten, and then to subsequent trophic levels.

Inorganic Matter Return

Decomposers break down dead organisms and waste products, transforming organic matter into inorganic nutrients that are returned to the environment for reuse by producers.

Energy Flow

Energy stored in the organic matter created by producers flows through the food chain to other trophic levels. Some energy is used for metabolic processes, and some is released into the environment as heat.

Ecosystem energy flow operates in an open circuit, with energy loss at each trophic level transfer. The 10% Law suggests that only about 10% of the energy stored in one trophic level is transferred to the next.

Biomass

Biomass is the total amount of organic matter at each trophic level, which can be used as a direct or indirect energy source.

Primary Biomass

Primary biomass is produced directly by autotrophic organisms (producers).

Secondary Biomass

Secondary biomass is produced by heterotrophic organisms (consumers).

Residual Biomass

Residual biomass is generated as a byproduct of human activities.