How Well Do You Know Food Webs?

Natural Interconnection of Food Chains:

• A food web is a graphical representation of what-eats-what in an ecological community

• Ecologists categorize life forms into two trophic levels: autotrophs and heterotrophs

• Autotrophs produce organic matter from inorganic substances through photosynthesis

• Heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs

• Food webs are limited representations of real ecosystems as they aggregate many species into trophic species

• Trophic levels are defined by the position of a species in the food web

• Trophic dynamics is the central concept in the transfer of energy from one part of the ecosystem to another

• Trophic cascades are indirect effects that can alter the abundance, distribution, or biomass in the trophic levels

• Biomass represents stored energy but concentration and quality of nutrients and energy is variable

• The biomass of each trophic level decreases from the base of the chain to the top due to entropy

• A food chain is a linear feeding pathway that traces monophagous consumers from a base species up to the top consumer

• Ecological pyramids are graphical representations of the biomass or productivity at each trophic level and can be used to quantify food web trophic structureOverview of Food Webs

• Ecological pyramids depict different numerical properties of ecosystems, including numbers of individuals, biomass, and energy.

• Pyramid structure can vary across ecosystems and across time, with some instances of biomass pyramids being inverted.

• Mineral and nutrient cycles trace food web energy pathways, with most of the primary production in an ecosystem being recycled by detritus back into useful nutrients.

• Food webs are necessarily aggregated and only illustrate a tiny portion of the complexity of real ecosystems.

• Different kinds or categories of food webs include human, agricultural, detrital, marine, aquatic, soil, Arctic (or polar), terrestrial, and microbial food webs.

• In a detrital web, plant and animal matter is broken down by decomposers and moves to detritivores and then carnivores.

• Ecologists collect data on trophic levels and food webs to statistically model and mathematically calculate parameters, such as those used in other kinds of network analysis, to study emergent patterns and properties shared among ecosystems.

• Complexity is a measure of an increasing number of permutations and it is also a metaphorical term that conveys the mental intractability or limits concerning unlimited algorithmic possibilities.

• Food webs are complex in the way that they change in scale, seasonally, and geographically, with components of food webs crossing the thresholds of ecosystem boundaries.

• Food webs serve as a framework to help ecologists organize the complex network of interactions among species observed in nature and around the world.

• The earliest graphical depiction of a food web was by Lorenzo Camerano in 1880, followed independently by those of Pierce and colleagues in 1912 and Victor Shelford in 1913.

• Interest in food webs increased after Robert Paine's experimental and descriptive study of intertidal shores suggesting that food web complexity was key to maintaining species diversity and ecological stability.

Challenge your knowledge on the interconnection of food chains with our quiz! Learn about the basics of food webs, trophic levels, and ecological pyramids. Explore the different types of food webs and how they vary across ecosystems. Test your understanding of trophic dynamics, biomass, and trophic cascades. Discover the complexity of food webs and how they serve as a framework for ecologists to understand the network of interactions among species. See how much you know about the history of food web