Question

Before the 1960s, most ecologists thought that the number of producers in an ecosystem was the only variable that limits the number of herbivores. The idea was that every level was regulated by the amount of food from the trophic level below it.

Answer 1

The complete question is as follows:

1. How did the green world hypothesis differ from this “bottom-up” view?

2. Imagine a simple food chain: Grass -> Grasshoppers -> Mice. If snakes that eat mice are added to the ecosystem, how would you redraw the food chain to represent this change?

3. After the snakes are added, would you expect the amount of grass to increase or decrease? Explain your reasoning.

Answer:

1. The green world hypothesis states that plants or producers are consumed in less quantity by herbivores due to predators and other conditions which is different from the hypothesis as it says the number of the herbivores are regulated by the organism above them in the food web instead of below.

2. before adding snake: Grass →Grasshoppers →Mice ( arrow towards predator)

After adding the sakes: Grass →Grasshoppers →Mice→Snakes. (as snakes eat mice so they will be added after mice)

3. The grasses will decrease as there would be fewer mice due to snakes and the number of grasshoppers will be high which leads to the decrease in the amount of grass.