They are called the primary consumers. This continues on, all the way up to the top of the food chain, and us. Because of this inefficiency, there is only enough food for a few top level consumers, but there is lots of food for herbivores lower down on the food chain, so there is room for fewer consumers than producers. Another way of looking at it is that it would only take a half acre of land to feed the people grain, but a whole acre if you feed the grain to the cattle and the cattle to the people. Solve the following problems mathematically.
Sharks eat tuna that eat mackerel that eat herring that eat copepods that eat diatoms.