One large tree supports 25000 insects. The insects are eaten by 400 small birds, and the birds are…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
One large tree supports insects. The insects are eaten by small birds, and the birds are eaten by hawks. The dry biomass is for the tree, for the insects, for the birds and for the hawks.
- Describe the shape of the pyramid of number.
- Describe the shape of the pyramid of biomass.
- What can you say about the pyramid of energy?
- A bird of this ecosystem eats both insects and fruits of the tree. Which limitation of the pyramids does this show?
Need a reminder? The key ideaShow
The pyramids of number, biomass and energy have the producers at the base. The pyramid of number of a tree and the pyramid of biomass of the sea can be inverted. The pyramid of energy is always upright. Production in a year is the biomass times the turnover.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) The numbers from the bottom are , , , . The base is the narrowest, the second bar is the widest, and the top is narrow. The pyramid of number is not upright. It is inverted at the base.
Step 2. (b) The masses are , , , . They fall at each step, so the pyramid of biomass is upright.
Step 3. (c) It is always upright, because the energy falls at each step.
Step 4. (d) The bird feeds at two trophic levels. A pyramid does not take into account a species that belongs to more than one trophic level.
Answer: (a) inverted at the base; (b) upright; (c) always upright; (d) one species at more than one level.
Discussion (0)
Log in to join the discussion.
Loading…