ESS 2.2 Energy and biomass in ecosystems

Ecosystem Sustainability

Ecosystems rely on continuous supplies of energy and matter.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Photosynthesis

The process where autotrophs convert light energy into chemical energy (glucose).

Cellular Respiration

The breakdown of glucose to release energy in a usable form.

Trophic Levels

The hierarchical stages in a food chain, beginning with producers.

Energy Flow

Movement of energy through food chains and ecosystems.

Second Law of Thermodynamics

Energy transformations are inefficient, leading to energy loss as heat.

Consumers

Organisms that obtain energy by consuming other organisms.

Carbon Transfer

Carbon compounds and their stored energy are passed through the food chain.

Energy and Biomass Loss

Energy is lost at each trophic level, limiting the number of levels.

Gross Productivity (GP)

The total biomass gained by an organism.

Net Productivity (NP)

Biomass remaining after energy loss from respiration.

Food Webs

Diagrams that illustrate complex trophic relationships in an ecosystem.

Biomass Measurement

Biomass can be quantified by drying and weighing samples.

Ecological Pyramids

Graphical representations of numbers, biomass, or energy at trophic levels.

Bioaccumulation

The buildup of pollutants in an organism over time.

Biomagnification

The increasing concentration of pollutants as they move up the food chain.

Non-Biodegradable Pollutants

Chemicals like PCBs, DDT, and mercury that persist in ecosystems.

Microplastics

Small plastic particles that absorb and transmit pollutants through food chains.

Human Impact on Energy Flow

Activities like fossil fuel burning, deforestation, and agriculture disrupt energy and matter flow.

Autotrophs vs. Heterotrophs

Autotrophs synthesize their own carbon compounds, while heterotrophs consume them.

Photoautotrophs

Use sunlight for photosynthesis.

Chemoautotrophs

Use inorganic chemical reactions for energy.

Primary Productivity

Rate of biomass production using an external energy source.

Secondary Productivity

Biomass gain by consumers from ingested food.

Net Primary Productivity (NPP)

The quantity of carbon compounds available for primary consumers.

Maximum Sustainable Yield (MSY)

The highest sustainable net productivity of a system.

Sustainable Yields

Higher at lower trophic levels due to energy availability.

Ecological Efficiency

The percentage of energy transferred from one trophic level to the next.

Entropy Increase

The Second Law of Thermodynamics explains that entropy (disorder) increases as biomass moves through ecosystems.