Chapter 6

energy flow
the transfer and transformation of high-energy organic molecules
trophic levels
feeding levels based on their source of food
food web
The feeding interactions among species in a community are best described as this.
food chains
Feeding relationships among organisms are often depicted as simplified food webs called this
Primary producers
transform energy from sunlight or certain inorganic chemicals into high-energy carbohydrates.
primary consumers
The second trophic level is composed of herbivores, such as grazing mammals and insects; animals that feed on primary producers are also called this.
organisms that feed on nonliving organic matter
biomass energy
Organisms at each trophic level transform what they eat into this, the food that can be consumed by higher trophic levels.
trophic level efficiency
The fraction of energy that the organisms in one trophic level make available to the next trophic level is called this.
Keystone species
Keystone species, so named in reference to the wedge-shaped keystone that holds an arched structure together, play a particularly important role regarding the abundance of other species. Not surprisingly, plant species that account for a significant portion of total primary production are often keystone species.
trophic cascade
in which the populations of herbivores increase, resulting in the overconsumption of primary producers.