Trophic Levels and Energy Flow in Ecosystems Trophic

Trophic Levels and Energy Flow in Ecosystems

Trophic level • Describes the position of organisms in relation to the order of nutrient and energy transfers in ecosystem • Organisms that eat the same type of food belong to the same trophic level • Ex: producers (plants) = 1 st trophic level (bottom) versus carnivores = 3 rd trophic level (top) as nutrients and energy flow from bottom to top.

Food Chain • A model that represents the pathway taken by nutrients and energy in relation to specific organisms.

Food Webs • Provide a more ACCURATE model/view of nutrient and energy pathways compared to food chain. • Displays complexity of Ecosystems!

Ecological pyramids/food pyramids • Used to illustrate pathway of energy in ecosystems • Three types: 1. Pyramid of Energy 2. Pyramid of Numbers 3. Pyramid of Biomass

Pyramid of Energy

Pyramid of Energy • Each block represents amount of energy available in each trophic level • Larger the block = more Energy • Producers @ bottom Carnivores @ top • On average, only 10% of the energy present in one trophic level is passed on to the next trophic level

Pyramid of Numbers • Represent actual # of organisms in each trophic level. • Wide variety of shapes • Depends on numbers of types of organism OR size of organisms

Pyramid of Biomass • Represent total mass of living things in each trophic level • Usually mass goes down with each trophic level

Discussion Questions • On average, how much energy is available to organisms in the third trophic level if 5000 k. J were available at the first trophic level? A. B. C. D. 5 KJ 5000 KJ