Food Chain, Food Web, and Ecological Pyramids

This set of vocabulary flashcards covers the fundamental concepts of food chains, food webs, and the various types of ecological pyramids as described in the lecture notes.

Food chain

The transfer of food energy from the producers, through a series of organisms with repeated eating and being eaten.

First trophic level

The position in a food chain occupied by producers.

Second trophic level

The position in a food chain occupied by primary consumers.

Trophic level

The term referring to an organism's position in a food chain.

Grazing food chain

A food chain that starts from green plants, goes to grazing herbivores, and ends in carnivores; it is directly dependent on the influx of solar radiation.

Detritus

Organic wastes, exudates, and dead matter derived from the grazing food chain.

Detritivores

A group of organisms that use detritus as a source of energy and are separate from the grazing food chain.

Detritus food chain

A food chain that depends chiefly on the influx of organic matter produced in other ecosystems rather than direct solar energy.

Food web

A network of food chains where different types of organisms are connected at different trophic levels, providing multiple options for eating and being eaten.

Eltonian Pyramids

Another name for ecological pyramids, named after Charles Elton who developed the concept.

Ecological pyramids

A diagrammatic representation of the relationship between numbers, biomass, and energy content of producers and consumers of different orders in an ecosystem.

Pyramid of numbers

A type of ecological pyramid that shows the number of individual organisms at each successive trophic level.

Upright pyramid of number

Seen in aquatic and grassland ecosystems where numerous small autotrophic producers support lesser numbers of herbivores and carnivores.

Partially upright pyramid of number

Seen in forest ecosystems where fewer producers support a greater number of herbivores which in turn support fewer carnivores.

Inverted pyramid of number

Seen in parasitic food chains where one autotrophic producer supports higher numbers of primary consumers, parasites, and numerous hyperparasites.

Pyramid of biomass

A pyramid showing the total amount of dry matter or living matter produced at each successive trophic level.

Biomass

The net organisms collected from each feeding level, which are then dried and weighed.

Upright pyramid of biomass

Occurs when the larger weight of producers supports a smaller weight of consumers, such as in a forest ecosystem.

Inverted pyramid of biomass

Occurs when the smaller weight of producers supports a larger weight of consumers, such as phytoplanktons in an aquatic ecosystem supporting larger weights of fish.