the movement of materials and energy through an ecosystem Ecosystem Ecology the movement of materials and energy through an ecosystem Section 22-1 Pages 415-419

Producers Manufacture their own food Capture energy and use it to make organic molecules There are two types: Photosynthetic = use energy from light Chemosynthetic = use energy from inorganic chemicals Examples = plants, protists, and bacteria

Gross Primary Productivity - is the rate at which producers in an ecosystem capture energy

Biomass - is the organic material in an ecosystem

Standing Crop Biomass

Net Primary Productivity = gross primary productivity – rate of respiration in producers is the rate at which biomass accumulates is expressed as: energy/area/year (kcal/m2/y) mass/area/year (g/m2/y)

Primary Productivity of Different Ecosystems

Consumers obtain energy by ingesting or consuming organic molecules made by other organisms grouped according to the food they eat Herbivores = eat producers Carnivores = eat consumers Omnivores = eat both producers and consumers Detritivores = eat garbage Decomposers = break down dead tissues and waste into smaller molecules

Movement of Stuff Through Ecosystems

Trophic Levels an organism’s position in the sequence of energy transfers most ecosystems contain only three or four trophic levels Producers = 1st level Herbivores = 2nd level Carnivores = 3rd level +

Movement of Energy

a pathway of feeding relationships Food Chain a pathway of feeding relationships

Food Chains

Grazing Food Chain

Food Web

Energy Movement & Nutrient Cycling

Pyramid of Net Production Note 10% energy transfer between trophic levels Pyramid of Net Production

Ecological Efficiency

Why is energy transfer so low? Energy is reflected. Energy is lost when some parts cannot be digested. Energy is lost as waste. Energy is lost in cellular respiration. Energy is lost as heat. Organisms die without being eaten.

Ecological Efficiency 100 * 6 / 67 = 9% 100 * 67 / 1478 = 4.5% Ecological Efficiency 100 * 3,368 / 20,810 = 17%

Pyramid Shape A diagram of trophic level relationships Width of bar correlates with the number Three primary types of diagrams Energy Biomass Population numbers

Biomass Pyramids

Pyramid of Numbers

Ecological Biomagnification