Earth, which means that once you understand these rules, all ecosystems make sense as interacting flows of energy and built complexity. Energy flows through every level of every trophic pyramid found in nature — and, as we shall see, in our economy as well — and nearly all of it eventually flows to outer space, as waste heat. TaaL: To convert one sort of critter into another by digesting it is thermodynamically wasteful. When a gazelle is digested it becomes a bit more “disordered” than a live one and needs to be entirely re -ordered to turn into parts of a lion. That uses up a lot of the energy formerly embodied in the gazelle. With this knowledge, you can infer that at any given time there’s a lot more biomass on each trophic level than the level above it. So for instance, if you wanted to feed a lot of humans on an overpopulated planet, it would make sense, and probably would be a necessity, to do so with things on low trophic levels, rather than, say, lionburgers or tuna (or cows). Humans tend to draw pyramids with large toothy creatures like themselves at the top, but one could just as validly show your pyramid upside down. The lower trophic levels are where most of the living on planet Earth takes place. The high trophic levels are a small and specialized niche in most of your ecosystems. If you want more of your kind to inhabit the future, you might consider eating lower down the food chain. Right now, in addition to mining the ancient sunlight embodied in fossils, Earth’s hominids are taking ~35% of what the daily sun grows on Earth for yourselves 92 ; more than your share, given you are one of up to 10 million or more species 93 . The Bottom Line: Due to energy losses, life is only about 10% efficient at creating biomass when it eats other living things. Trophic levels can be represented as a pyramid: there is far less biomass possible as the levels increase; always more mice than lions .
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