Talk:Trophic dynamics

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The presentation on this page looks overly academicized. It lacks a description of energy tranfer efficiency between trophic levels and contains a lot of material on production levels in different biomes that really is irrelevant to the concept of energy metabolims in the environment. Really needs an ecologist to along and fix it up. A Primack

3 trophic levels is the usual case, but 4 and 5 are found as well; 6 levels exist but is really exceptional. Anthère

Including information on the maximum number of levels found would be good - I believe 6 is basically the limit, but I haven't got any source for this right now. Richard001 07:25, 15 May 2007 (UTC)[reply]

I think that this page should probably be condensed and the links improved. Much of what is on this page is irrelevant, and much of the rest is better covered on other pages, including trophic pyramid, primary production, food web, soil food web, biodiversity. Justinleif 18:12, 13 March 2007 (UTC)[reply]

I think this page would be much more useful if a section were devoted to humans, showing that it is much more efficient (and healthy) for humans to eat plants than to eat animals. User:BillShurtleff 24 April 2007

That's a good idea. The topic is well covered on the environmental vegetarianism page, but it would be good to mention it and link to it here, or perhaps on the trophic pyramid, which discusses the efficiency of transfer between trophic levels. This is probably not the place to discuss the health benefits of vegetarianism, but definitely the efficiency argument. I am considering revising this page (primarily by shortening it and improving the links), and will include your idea if I get around to it. Cheers Justinleif 20:12, 24 April 2007 (UTC)[reply]

There's something wrong with this phrase: "The only known exception to this is in deep sea hydrothermal vents chemosynthetic archaea form the base of the food chain).", namely, the lack of an opening parenthesis. Could someone fix this, please? ;) -- Anonymous Coward —Preceding unsigned comment added by 85.139.134.186 (talk) 14:15, 2 September 2007 (UTC)[reply]

producers

picture of list of pruducers —Preceding unsigned comment added by 66.229.49.230 (talk) 22:20, 23 October 2008 (UTC)[reply]

A question regarding numbering of trophic levels

Consider this food chain:

Organism P is a plant. This is trophic level 1. Organism A is a herbivore that feeds on P. It's trophic level is 2. Organism B is a carnivore that feeds on A. It's trophic level is 3. Organism C is a carnivore that feeds on B. It's trophic level is 4.

Now suppose there is a fifth organism, D. This is a carnivore that feeds on all the above animals, A to C. What is this creature's trophic level? Is it level 5 (i.e. based on the longest potential food chain it is involved in), or 3 (i.e. based on the shortest)?

Wardog (talk) 13:43, 23 March 2009 (UTC)[reply]

According to the article, "Secondary Consumers ... can consume the two levels before it. ... Tertiary Consumers can eat all three levels below them." That implies that the trophic level is based on the longest food chain, so your hypothetical apex predator is at level 5. My understanding is that these levels only apply to eating the adult form of the organism -- so if organism C eats herbivore A and small, immature forms of carnivore B (but not the full-grown carnivore B), then C only counts as being at level 3, and D only counts as at level 4.

Consider this food chain:

Grass is a plant, at trophic level 1.

A zebra is a herbivore that feeds on grass, at trophic level 2.

A lion will kill and eat a zebra.

Occasionally a crocodile will kill and eat a lion (in the water).

Occasionally a lion will kill and eat a crocodile (on land).

That last line puts a "loop" in the food web. Does that put lions at (potentially) "infinite" trophic level? In such a region, are both crocodiles and lions considered apex predators, or does this region have no apex predators? --68.0.124.33 (talk) 03:35, 19 April 2009 (UTC)[reply]

Usually, trophic levels are calculated as weighted averages rather than as the "maximum" possible length of the food chain; this eliminates the possibility of "infinite trophic levels". For example, Pimelodus pictus has an average estimated trophic level of 3.19 in the wild, meaning that it mostly eats herbivorous fish, but once in a while it will instead eat a carnivore. The probability of lion-crocodile-lion-crocodile "infinite loops" (as you mentioned) is vanishingly low, so it would contribute very little to the animal's actual trophic level. Lions probably have an average trophic level slightly above 3; usually they eat herbivores, but don't necessarily have to (some lions have been known to eat seals, who themselves have trophic levels around 4 since they primarily feed on fish). For humans the average trophic level could be anywhere from 2 (for vegetarians) to 4 (for humans who primarily eat fish). Stonemason89 (talk) 20:57, 19 February 2010 (UTC)[reply]

Competition

I am surprised that this article does not even mention competition anywhere. While consumption should be the focus in trophic levels, shouldn't competition be at least mentioned somewhere. MATThematical (talk) 21:17, 21 February 2010 (UTC)[reply]

Suggested move

Trophic dynamics should not have a main article - but should be nested as a sub-heading within food web. It was a title on a paper in 1942 by Lindeman - [1] - who discussed food cycles (which is synonymous with food web). I'm working on food web and finding it difficult to think of ways to organize the links here. Trophic level deserves a main article page - but trophic dynamics is pretty much synonymous with food web.Thompsma (talk) 21:51, 13 June 2011 (UTC)[reply]

Speedy deletion

I have requested a speedy deletion. Please see discussion in food chain. This is actually a merger between trophic dynamics, food web, food chain into food web.Thompsma (talk) 00:06, 14 June 2011 (UTC)[reply]