Energy Flow Through Ecosystems

Vocabulary flashcards covering key terms related to energy flow, trophic levels, primary production, and matter cycling in ecosystems.

Ecosystem

The sum of all organisms in a given area and the abiotic factors they interact with.

Biotic factors

Living or once living components of an environment.

Abiotic factors

Nonliving physical and chemical properties of the environment.

First law of thermodynamics

Energy cannot be created or destroyed, only transferred; chemical elements are continually recycled in the environment.

Second law of thermodynamics

Exchanges of energy increase the entropy of the universe.

Net gain in energy

Energy surplus that results in storage or growth of an organism.

Net loss in energy

Energy deficit that results in loss of mass and eventual death.

Metabolic rate

Total amount of energy an animal uses in a unit of time.

Metabolic rate measurement methods

Measured in calories, heat loss, or by oxygen consumed (or CO2 produced).

Body mass relation to metabolic rate

Smaller organisms tend to have higher metabolic rates; larger organisms have lower metabolic rates.

Endotherms

Maintain body temperature using metabolic energy.

Ectotherms

Regulate body temperature using external sources (sun, shade, or other organisms).

Trophic levels

Groups of species based on main source of nutrition and energy.

Energy cannot be recycled

Energy flows through ecosystems; the sun continually supplies energy.

Primary producers (autotrophs)

Use light energy to synthesize organic compounds (plants, algae, photosynthetic plankton; some chemosynthetic bacteria/archaea).

Chemosynthesis

Producing food using energy from chemical reactions rather than light (e.g., some bacteria and archaea).

Heterotrophs

Rely on autotrophs; cannot make their own food.

Primary consumers

Herbivores.

Secondary consumers

Carnivores that eat herbivores.

Tertiary consumers

Carnivores that eat other carnivores.

Decomposers

Get energy from detritus; include fungi and many prokaryotes; important for recycling chemical elements.

Food chain

Transfer of food energy up the trophic levels.

Food webs

Linked food chains in a community.

primary production

the amount of light energy that is converted to chemical energy

Gross primary production (GPP)

Total primary production in an ecosystem.

Net primary production (NPP)

GPP minus the energy used by primary producers for respiration (Ra).

Secondary production

The amount of chemical energy in a consumer’s food converted to new biomass.

10% transfer efficiency

About 10% of energy is transferred from one trophic level to the next.

Matter cycling

Matter moves through ecosystems and is recycled; energy is not recycled.

Biogeochemical cycles

Nutrient cycles that involve both biotic and abiotic factors (water, carbon, nitrogen, phosphorus).

Water cycle

Cycle of water; essential for life and influences ecosystem processes.

Carbon cycle

Cycle of carbon essential for formation of organic compounds.

Nitrogen cycle

Cycle of nitrogen important for amino acids, proteins, and nucleic acids.

Phosphorus cycle

Cycle of phosphorus important for nucleic acids, phospholipids, and ATP.