1. Feeding Levels Grade 9 Dr. Bennett

2. Trophic Levels Ecosystems are made up of several feeding levels, or trophic levels. 1 st = producers (plants) 2 nd = primary consumers (herbivores) 3 rd = secondary consumers (carnivores) 4 th = tertiary consumers (top carnivores)

3. Pyramid of Numbers A pyramid of numbers represents the concept that the numbers of organisms decrease as one progresses towards the top of the food chain. (example, grassland ecosystem) There are exceptions to this patterns. For example, in a reverse pyramid of numbers, a single tree may feed thousands of plant-eating insects.

4. Pyramid of Biomass A pyramid of biomass shows that biomass decreases from each trophic level to the one above. The biomass indicates how much of a particular organism there is in an ecosystem.

5. Pyramid of Energy Flow A pyramid of energy flow measures the total chemical energy that flows through each trophic level. Why is it impossible to invert a pyramid of energy flow? Because there is always less energy available for each successive (higher) trophic level in a pyramid.