Three Types of Ecological Pyramids
Pyramid of Numbers:
Grassland (UPRIGHT) Tree Ecosystem (INVERTED)
△ ▽
Hawk (few) Insects (many)
Snake (more) Caterpillars
Frog (more) Beetles
Insect (many) → One Tree (1)
Grass (most)
Pyramid of Biomass:
Terrestrial (UPRIGHT) Aquatic (INVERTED)
△ ▽
Hawks (tiny) Zooplankton (more)
Snakes (small) Phytoplankton (fewer)
Frogs (medium) → High phytoplankton turnover!
Insects (large)
Grass (HUGE mass)
Pyramid of Energy:
ALWAYS UPRIGHT (both terrestrial and aquatic)
△
$T_{4}$ (least energy)
$T_{3}$ (more)
$T_{2}$ (more)
$T_{1}$ (MOST energy - producers)
Summary Table
| Pyramid | Terrestrial | Aquatic | Always Upright? |
|---|---|---|---|
| Numbers | Usually upright; INVERTED in tree ecosystem | Usually upright | NO |
| Biomass | Upright | INVERTED (phytoplankton turnover) | NO |
| Energy | ALWAYS UPRIGHT | ALWAYS UPRIGHT | YES |
NEET rule: Only pyramid of energy has NO EXCEPTIONS.