Environmental Pyramids
Energy pyramid: describes the feeding and energy relationships within a food chain or web.
The pyramid shows how much energy is lost. At some point the pyramid will stop due to lack of energy.
An Energy Pyramid3rd
Level
Consumers
Secondary
Consumers
Primary Consumers / Producer organisms represent the greatest amount of living tissue or biomass at the bottom of the pyramid.
The organisms which occupy the rest of the pyramid belong to the feeding levels indicated in each step.
Pyramid of Numbers
Shows the number of organisms (or population) that feed on the next trophic level. Usually a large number of producers are required to feed a smaller number of primary consumers and so on.
Example 1: Upright Pyramid of Numbers Example 2: Inverted Pyramid of Numbers
Pyramid of Biomass
Shows the total mass of organisms available in each trophic level of an ecosystem. It takes into account the size of the organisms. It is measured in kilograms (kg).
Example 1: Upright Pyramid of Biomass Example 2: Inverted Pyramid of Biomass
Pyramid of Energy Flow
Shows the amount of nutrient energy at each trophic level, which is difficult to measure. A pyramid of energy flow is always upright. It is measured in kilojoules (kJ).
Example 1: Upright Pyramid of Energy Flow
Reinforcement – Identifying Pyramids
Directions: Fill in the pyramids by placing the information on the appropriate levels and identify the type of ecological pyramid in the blank to the right of the diagram.
Ex1. 75 000 blades of grass, 7500 beetles, 750 sparrows, 75 snakes, 7 hawks
Type of pyramid ______Ex2. 5000 kg of roots, 500 kg of mice, 50 kg of cats, 5 kg of snakes, 0.5 kg of hawk
Type of pyramid ______Ex3. Grass captures 67 000 kJ of energy from the Sun. Rabbits eat the grass, and snakes eat the rabbits. The wolf, which preys on rabbits and snakes, is the top carnivore.
Type of pyramid ______Complete these two pyramids in the space provided.
1. Oak seeds contain 43000 kJ. The seeds are eaten by a deer that is eaten by a cougar. Which of the three kinds of ecological pyramids is this?
Type of pyramid ______2. 5200 plankton are eaten by a shrimp. Clownfish consume shrimp. Clownfish are consumed by sharks. Sharks can be eaten by orca whales. Which of the three kinds of ecological pyramids is this?
Type of pyramid ______Review Questions - Check Your Understanding
1. Which would you expect to have the greatest biomass in an ecosystem: a population of rabbits or a population of foxes? Why?
2. Why are there rarely more than four links in a food chain?
I am studying an ecosystem of grass, dogs and fleas. Sketch a food chain and label the producer, primary consumer and secondary consumer. Would a pyramid of numbers be upright or inverted? Sketch it.