What is exactly is trophic structure?

Question

I've looked up the word on the internet but there isn't much. All I've gathered so far is that it is the feeding relationships of a community.

Any more information would be great! Examples are always helpful. Thank you.

Answer 1

I'm a high school bio teacher.  Just so you know that i probably know a little, at least, about what i'm discussing here.

Trophic structure is the relationship of an organism to other organisms in the context of a food web.  FOOD WEB, the idea, words and pictures, could actually be substituted for the "trophic structure" without much distortion in meaning.

Here's a good pictorial example of a food web: http://www.scientific-art.com/portfolio%...

Here's another:  http://www.stephsnature.com/images/Websi...

Here's another: http://www.coloradocollege.edu/dept/ev/c...

Another:  http://staff.tuhsd.k12.az.us/gfoster/sta... (This one is good.)(Well, they're all good or i wouldn't use them but this one is really good.)

Another, specifically called "Trophic levels" instead of "food web" or another term that means the same thing: http://www.mesa.edu.au/friends/seashores...

Please look at at least one of the above illustrations during this wordy part.  It'll make more sense.  (I'd have something like this on the overhead in my classroom, were we there.)

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The sun is the basis of all life on Earth.  It's the energy (food) for everything else, either directly or indirectly.

In any biological system—a habitat (a pond, an oak forest, a high plains desert, a shallow underwater reef, etc)--what defines different trophic structures (or systems) is the amount of energy available to the organisms in the different trophic levels. The available energy of all/any trophic structures is almost always represented by a pyramid.  

The total number of organisms that can use that energy in the pyramid is called the biomass. Energy (in the form of food) is transferred from each level of the trophic pyramid to less numbers of other creatures above it in the trophic pyramid.  

(LOOK at one of the visuals! Really!  It'll help, i swear!)

The bottom level of the pyramid contains the autotrophs--organisms that get their food from the sun (photosynthesis). The autotrophs are the producers. Almost always, AUTOTROPHS = PLANTS.

There are usually more than one autotroph in any particular trophic level.  All other autotrophs in the environment are known as secondary producers. The primary producers are the dominant form of producers.

The second level is made up of the primary consumers. Primary consumers are organisms that receive their energy directly from the autotrophs (no other organisms are in between them). In any habitat there are going to be a bunch of primary consumers.  Almost always, PRIMARY CONSUMERS = HERBIVORES.

If the organism eats anything besides the autotrophs/plants, it occupies other trophic levels while still being a part of the second level, the primary consumers.  Sometimes PRIMARY CONSUMERS = OMNIVORES, too.

Secondary consumers receive their energy from (eat) other heterotrophs (things that have to eat other things to live, they cannot get their food directly from the sun). SECONDARY CONSUMERS = CARNIVORES.

The fourth level of any/all ecosystem (or trophic structure) are the members that are least likely to be eaten by any other member of the ecosystem—the top carnivores.

By the time that the energy is transferred through all of living members of the ecosystem, the top carnivore receives only teeny tiny percentage of the original amount of energy (food) available.

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Go here:  http://www.sciencebitz.com/?page_id=49 for a basic explanation, with graphics.