Section 2.2

Vocabulary Autotroph - Any organism that collects energy from sunlight inorganic substances to produce food. Heterotroph – An organism that gets its energy requirements by consuming other organisms.

Herbivore - Heterotrophs that only eats plants Carnivore – Heterotrophs that only eat other heterotrophs Omnivore – Heterotrophs that eat both plants and animals. Detritivores – Organisms that eat fragments of dead matter in an ecosystem, return nutrients to the soil, air, and water where the nutrients can be reused by other organisms.

Trophic Level – Each step in a food chain or food web Food Chain – A simple model that shows how energy flows through an ecosystem. Food Web – A model representing the many interconnected food chains and pathways in which energy flows through a group of organisms. Biomass – The total mass of living matter at each trophic level.

Outline Flow of Energy in an Ecosystem Autotrophs capture energy, making it available for all members of a food web. Heterotrophs get their energy by consuming other organisms. There are four types of heterotrophs, herbivores, carnivores, omnivores and detritivores.

Models of energy flow Food chains and food webs are representations of energy flow. Each step is referred to as a trophic level. Ecological pyramids show how matter and energy move through an ecosystem