Secondary Production and Trophic Efficiency

by Jason Amores Sumpter
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secondary production is the amount of energy converted to new biomass by hetero troughs. And we're going to be looking at the production efficiency of hetero troughs, which is how much energy is stored in an organism from the food that it eats. Now, energy is stored after excreting a bunch of that is waste and using some for respiration. So this is usually very inefficient. And as you can see here, we have an example of secondary production where this frog is going to be ingesting food, it's going to assimilate it. I mean, you know, extract the nutrients and whatnot. Some of that energy is going to be lost due to respiration, and some is going to be wasted as feces. And, of course, a lot of these frogs, they're just gonna die. So you know, there goes that, But some some small amount is going to be added as new biomass, and that is going to represent the production efficiency now in ecosystems. We're gonna wanna look at the trophic efficiency, which is how much energy has passed between the trophic levels of the food web, and usually this is Onley about 10%. So this is highly inefficient. In fact, this could range from about 5 to 20% but 10% is just a good estimate toe work with, and it's nice round number. So if we assume that approximately 10% of the energy and biomass and one trophic level gets transferred to the next trophic level, we can construct what's called a pyramid of net production. That's going to show the net production of biomass at each level So we can see this, uh, you know, theme the energy transfer in this pyramid. So assuming that what the primary producers have, we'll just call that 100%. I'm actually gonna switch to read just so it shows up. So the primary producers, that's 100% right there. That means the primary consumers are only going to get about 10% of the total energy. That was, um, uh, you know, storage and biomass of primary producers. So those primary consumers only get 10% of this 100% of the bottom of the pyramid. Now, these secondary consumers get on Lee 1% of what was on the bottom of the pyramid because they only get 10% of the rung just below them from the primary consumers, so they get 10% of what the primary consumers got. But the primary consumers only got 10% so they're only getting 1% of this base of the pyramid. Likewise, the third level is only going to get 10.1% so you can see that this is incredibly inefficient now. We can also sometimes be interested in looking at a biomass pyramid, which is going to show the amount of biomass stored in living tissue at each trophic level. And hopefully from this energy pyramid. You guessed that most of the biomass is going to be concentrated at the bottom of these pyramids, and as we move up in trophic levels, it is going to get much, much smaller. Now with that, let's go ahead and flip the page.