Transfers of Energy and Matter

What is ecology?

The study of relationships between living organisms and their environment, including biotic and abiotic factors.

Define ecosystem.

A community of organisms and their surroundings, including biotic and abiotic factors, which interact with each other.

Are ecosystems open or closed systems?

Ecosystems are open systems because energy and matter can enter and exit.

What is the principal source of energy for most ecosystems?

Sunlight, except for ecosystems relying on hydrogen sulfide (H2S) instead.

What are biotic factors?

Living components of an ecosystem, like animals, plants, and microorganisms.

What are abiotic factors?

Non-living components of an ecosystem, such as water, soil, and temperature.

Define species.

Groups of organisms that can potentially interbreed to produce fertile offspring.

What is a population?

All individuals of a species living in the same area at the same time.

How does reproductive isolation affect evolution?

It can lead to the development of new species over time.

What is a food chain?

A sequence of organisms through which energy flows via feeding relationships.

What is biomass?

The total dry mass of organisms in an ecosystem.

Define producer.

An organism that uses light or chemical energy to create its own food (e.g., plants).

What is the role of consumers in a food chain?

They feed on producers or other consumers, transferring energy through the chain.

What do the arrows in a food chain represent?

The flow of energy from one organism to the next.

Define trophic level.

The position of an organism in a food chain, indicating its feeding relationship to others.

What percentage of energy is passed to the next trophic level?

About 10% of the energy is passed to the next level.

Why is there energy loss between trophic levels?

Due to heat loss from cellular respiration and organic matter not consumed.

What limits the number of trophic levels in an ecosystem?

Energy losses at each trophic level reduce the available energy for higher levels.

Define autotroph.

An organism that produces its own food from inorganic substances, using light or chemical energy.

What is carbon fixation?

The process by which autotrophs convert inorganic carbon (CO2) into organic compounds.

Define heterotroph.

An organism that obtains organic carbon compounds from other organisms.

What is the role of detritivores and saprotrophs in ecosystems?

They break down dead organic matter, recycling nutrients back into the ecosystem.

Define primary production.

The accumulation of carbon compounds in biomass by autotrophs.

What is secondary production?

The accumulation of biomass by heterotrophs from consuming other organisms.

How is net primary production (NPP) calculated?

NPP = Gross Primary Production (GPP) - Respiration (R).

What is a carbon sink?

An environment that absorbs more CO2 from the atmosphere than it releases (e.g., forests, oceans).

What is a carbon source?

A process or environment that releases more CO2 into the atmosphere than it absorbs (e.g., burning fossil fuels).

What is the Keeling Curve?

A graph showing the concentration of CO2 in Earth’s atmosphere over time.

Define flux in the carbon cycle.

The movement of carbon atoms through Earth's different environments.