APES Unit 1: Module 6

Producers

Plants, algae, and some bacteria that use the Sun’s energy to produce usable forms of energy, such as sugars (autotrophs)

Cellular respiration

The process by which cells unlock the energy of chemical compounds

Anaerobic respiration

The process by which cells convert glucose into energy in the absence of oxygen

Equation NPP

NPP = GPP - R

Primary productivity

The rate of converting solar energy that producers in an ecosystem capture via photosynthesis over a given amount of time

Gross primary productivity (GPP)

The total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given amount of time

Net primary productivity (NPP)

The energy captured by producers in an ecosystem minus the energy producers respire

Biomass

The total mass of all living matter in a specific area

Standing crop

The amount of biomass present in an ecosystem at a particular time

How do photosynthesis and respiration affect energy flow?

Photosynthesis captures the energy of the Sun to convert CO2 and water into carbohydrates, respiration, whether aerobic or anaerobic, unlocks the chemical energy stored in the cells of organisms

What are the calculations for gross primary productivity and net primary productivity?

Ecosystem productivity can be quantified by measuring the total amount of solar energy that producers capture, which is gross primary productivity, or by measuring the total amount of solar energy captured minus the amount of energy used for respiration, which is net primary productivity

Why does primary productivity have low efficiency?

The low efficiency occurs because producers can only capture about 1 percent of all available solar energy. The remainder is lost as heat to the atmosphere, including those wavelengths of light that are not usable by the producers

Why are some ecosystems much more productive than others?

Producers have the highest rates of primary productivity in ecosystems with warm temperatures, plenty of available water, and high concentrations of nutrients