Ecological Pyramids

Ecological Pyramid An ecological pyramid is a graphical representation designed to show the number of organisms, energy relationships, and biomass of an ecosystem. Succeeding levels in the pyramid represents the dependence of the organisms at a given level on the organisms at lower levels.

Three Types of Ecological Pyramids Pyramids of Production (Energy) Pyramids of Biomass Pyramids of Numbers

Pyramids of Production Represents the loss of energy with each transfer in a food chain. Pyramids of Production is always upright as the total amount of energy available for utilization in the layers above is less than the energy available in the lower levels. This happens because during energy transfer from lower to higher levels, some energy is always lost.

Pyramids of Production cont. -Trophic levels are stacked in blocks, with primary producers forming the foundation of the pyramid -Size of each block is proportional to the net production, expressed in energy units, of each trophic level.

Pyramids of Biomass Represents the amount of energy contained in a biomass, at different trophic levels for a particular time. Demonstrates the amount of matter lost between trophic levels. Two types of biomass pyramids: upright and inverted. -Biomass is a renewable organic (living) material.

Pyramids of Biomass cont. -upright pyramid:one where the combined weight of producers is larger than the combined weight of consumers. (ex-forest ecosystem) -inverted pyramid:one where the combined weight of producers is smaller than the combined weight of consumers. (ex-aquatic ecosystem) -measured in grams per meter2 or calories per meter2 -each level is dependent on its lower level for energy, hence the lover level determines how much energy will be available to the upper level Upright Inverted

Pyramids of Numbers Represents the number of organisms in each trophic level. Plot of relationships between the number of herbivores (primary consumers), first level carnivore (secondary consumers), second level carnivore (tertiary consumers) and so forth. Shape varies form ecosystem to ecosystem because the number of organisms at each level is variable.

Pyramids of Numbers cont. -upright, partly upright, and inverted are 3 types of pyramids of numbers.