APES Vocab Unit 1- Section: Food Chains & Webs

Food Web

A complex network of feeding relationships among various organisms in an ecosystem, illustrating how energy and nutrients flow through multiple interconnected food chains.

Food Chain

A linear sequence of organisms through which nutrients and energy pass by being eaten.

Positive Feedback Loop

A process where the effects of a small disturbance in a system lead to an increase in that disturbance, causing a continuous acceleration in the system's output.

Negative Feedback Loop

A system where the output or response enhances or amplifies the initial stimulus, leading to increased deviation from a set point.

Autotrophs

Organisms that produce their own food.

Heterotrophs

Organisms that must consume other organisms for food.

Consumer

An organism that obtains its energy by feeding on other organisms, including plants and animals, incapable of photosynthesis.

Herbivore

An organism that feeds on plants or plant-based materials.

Carnivore

An organism that feeds on other animals.

Trophic Levels

The hierarchical levels in an ecosystem, defined by the position of organisms in a food chain, where each level represents a different stage of energy transfer.

The 10% Rule

The principle that only 10% of the energy from one trophic level is passed on to the next level in a food chain, while the remaining 90% is lost as heat or used for metabolic processes.

Primary Productivity

The rate at which organic matter is produced by autotrophs in an ecosystem, often measured in terms of biomass or energy per unit area over time.

Gross Primary Production (GPP)

The total amount of organic matter produced by photosynthesis in a given area before any is used by autotrophs for respiration.

Net Primary Production (NPP)

The amount of organic matter produced by autotrophs in an ecosystem after accounting for the energy used in respiration. NPP represents the actual growth available for consumption by herbivores and decomposers.

Photosynthesis

Producers use solar energy to convert carbon dioxide and water into glucose and oxygen.

Respiration

Opposite of photosynthesis, consumers convert glucose and oxygen into water and carbon dioxide in order to release that energy.