1. Energy in Ecosystems

2. Food Web: a group of food chains showing all of the feeding relationships in an ecosystem. Trophic level — a layer in the feeding relationship of an ecosystem, one link in the food chain/web. Biomass — total amount of organic material present in a trophic level. Organic = is currently living or lived in the past So, all producers are at the same trophic level and all primary consumers are at the next trophic level. All Food Webs: Original Energy (SUN) Producers Consumers Decomposers Soil Arrows showing energy flow!

3. Energy/Ecological Pyramids Another way to look at trophic levels. a diagram showing the relative amounts of energy/biomass in the different trophic levels. Lowest trophic levels are at the bottom: Producers have the greatest biomass. http://www.earthforce.org/files/1284_image2_Energy_Pyramid_for_ Galvbay.jpg http://www.vtaide.com/png/foodchains.htm

4. Example of an Energy Pyramid MAN FOX RABBIT 100 % of the sun’s energy 10% 1% 0.1% 10% 1 MAN 10 FOXES 100 RABBITS 1000 Bunches of GRASS 90% Energy Lost during conversion to heat, waste…. Grass Rabbit - The decreasing size of the pyramid shows that each level of the pyramid has a smaller and smaller number of those organisms.

5. Carrying Capacity: The maximum population a community can tolerate for extended periods of time. Usually determined by abiotic factors … Community = the plants and animals found in an area Population: How many of a specific species can live in an area? Abiotic Factors = non-living characteristics of the environment. For example: -Sunlight -Moisture -Space -Pollution -Landscape/Terrain An extended period of time … the environment remains healthy and future generations of organisms are able to continue to live within the community

6. Limiting Factors: Anything that keeps a population from over-growing the resources available. Consider how changing the factors that affect carrying capacity can alter the population size of a species. Disease Parasites Accidents Fire Floods Storms Starvation Hunting Predation Habitat Loss Drought Pollution Shade