ESS Energy, Biomass and Ecosystems

Trophic levels

An organism's role in the flow of energy within an ecosystem, signifying a stage in the transfer of energy and nutrients.

Autotrophs/Primary producers

Organisms that synthesize their carbon compounds from inorganic sources of carbon and other elements.

Consumers

Organisms that gain chemical energy from carbon (organic) compounds obtained from other organisms.

Herbivores

Consumers that feed primarily on plants and other photosynthetic organisms.

Detritivores

Consumers that feed on dead organic matter, particularly plant detritus, and perform internal digestion.

Predators

Consumers that hunt, capture, and kill other animals for food.

Parasites

Consumers that live on or inside a host organism, deriving nutrients at the host's expense.

Saprotrophs

Organisms that feed on decaying organic matter by secreting digestive enzymes and absorbing the resulting nutrients.

Scavengers

Consumers that feed on carrion and decomposing organic matter, playing a role in cleaning the environment.

Decomposers

Organisms that break down dead organic material into simpler substances.

Food chain

Illustrates the sequential transfer of energy and nutrients among organisms within an ecosystem.

Heterotrophs

Organisms that cannot synthesize their own carbon compounds from inorganic sources.

Photoautotrophs

Organisms that use light energy to drive the process of photosynthesis.

Chemoautotrophs

Organisms that obtain energy from the oxidation of inorganic molecules to synthesize organic compounds.

First Law of Thermodynamics

Energy can be transformed but not created or destroyed.

Second Law of Thermodynamics

When energy is transformed, some must be degraded into a less useful form, and total entropy always increases.

Photosynthesis

Process that transforms light energy into chemical energy in the form of glucose.

Cellular Respiration

Process by which organisms break down glucose to release stored chemical energy.

Entropy

Measure of disorder or randomness in a system.

Food webs

Show the complexity of trophic relationships in communities and interconnectedness between food chains.

Trophic Efficiency

Percentage of energy transferred from one trophic level to the next.

Biomass

Total mass of living material present in a specific area or among organisms in a trophic level.

Pyramid of Numbers

Diagrammatic representation of the numbers of different organisms at each trophic level.

Pyramid of Biomass

Represents biomass at each trophic level at any one time.

Pyramid of Energy or Productivity

Represents the rate of flow of energy through each trophic level over a fixed period.

Gross Productivity

Total gain in biomass over a specific period.

Net Productivity

Amount of biomass remaining after losses due to respiration.

Primary Productivity

Rate at which primary producers convert inorganic carbon and other elements into organic compounds.

Gross Primary Productivity

Rate of solar energy captured in sugar molecules during photosynthesis.

Net Primary Productivity

Amount of biomass remaining after energy losses in primary producers.

Secondary Productivity

Rate at which consumers convert chemical energy in their food into biomass.

Gross Secondary Productivity

The amount of biomass assimilated after fecal loss.

Net Secondary Productivity

Rate at which consumers produce biomass remaining after respiratory losses.

Maximum Sustainable Yields

Largest yield that can be taken from a species' stock over an indefinite period.

Ecological Efficiency

Ratio of energy transferred from one trophic level to the next relative to the energy received.

Non-Biodegradable Pollutants

Substances that do not break down naturally, persisting for long periods and causing ecological harm.

Polychlorinated Biphenyls (PCBs)

Industrial chemicals used in electrical equipment that are highly persistent and toxic.

Bioaccumulation

Gradual build-up of non-biodegradable pollutants in an organism over time.

Biomagnification

Accumulation of non-biodegradable pollutants in organisms, leading to higher concentrations in predators.

Microplastics

Tiny plastic fragments or particles less than 5 millimeters in diameter.