Why does biomass in an ecosystem decrease at higher trophic levels of an ecosystem?

Answer 1

It's really because it takes much longer to grow than to be eaten.

Trophic levels have to do with how far removed you are from being a primary producer. Plants and the like are close to the lowest trophic level, because all they generally need is sun and dirt. On the other hand, if you only eat the cows that eat the grass, you are at least two steps away.

Which is important for exactly the reason you cite. Plants can grow as long as there's room for them. But a cow depends on having enough plants around to keep it alive. Metabolism isn't 100% efficient and even if it were you have to use some energy for moving around, reproducing, and the like, so there simply can't be as many cows as there are plants.

Of course it isn't EXACTLY mass that's important here, really. But it's a very good approximation - there's about so much energy to be gained per unit volume of a creature, and so much that's needed to support a certain volume, and volume correlates with mass, so it all comes out pretty much the same.

Even if the plants were to suddenly grow super-fast so you could support more cows, that would still mean a lot more plants too! And if the cows were much smaller so they didn't need as many plants to stay alive, you'd need more of them to make up the same amount of mass. So there just isn't much of a way around a decreased biomass with each increase in trophic level.

Answer 2

well the higher up the trophic level you go the further you are from organisms which produce energy from sunlight. Biomass is the material that is alive or once living, so her goes the grass grows, the rabbit eats the grass and a lion eats the rabbit the. it takes much more grass pound per pound to feed enough rabbits to feed a lion get it?

Answer 3

For the first 3 questions, the answer is a decrease. energy usually decreases about tenfold per trophic level. Biomass and organism abundance usually decreases. The concentration of toxins however increases, because those move through the trophic levels without being lost and as the biomass decreases this means the concentration per tissue increases.

Answer 4

Biomass? Like how many predators, etc?

10,000 blades of grass feeds
1,000 mice

1,000 mice feeds 100 cats.

100 cats feed 10 falcons.

Like that, sort of?

Well, I hope it was somewhat useful.

Answer 5

The air is lighter.