Energy Flow Through Ecosystems energy pyramids biomass pyramids

Energy Flow Through Ecosystems - energy pyramids -biomass pyramids -bioaccumulation/biomagnification

Energy Pyramid/Ecological Pyramid Shows how energy flows through an ecosystem The sun: provides initial energy through photosynthesis The first trophic level is composed of autotrophs

Sample Energy Pyramid

Energy Pyramid At each trophic level 90% of the energy is LOST as HEAT or due to life processes Only 10% of energy is transferred from one trophic level to another

Based on Heat this pyramid, what is Heat happening to the energy? Heat

Biomass Pyramid • Shows the WEIGHT of living material at each trophic level Each bar of the biomass pyramid represents the amount of biomass within a trophic level Biomass decreases with each trophic level

Pyramid of Biomass

What do you think happens when pesticide is sprayed? Where does it go? Does it only target the animal it is intended for?

Bioaccumulation • The building up (accumulation) of a toxic substance in an organism • The toxin builds up, and remains in the fatty tissue of an organism

Biomagnification • The concentration of the toxic substance increases as you go up a food chain • It becomes more deadly as you go up the food chain

Top Predator Hg = Mercury Where is the most Mercury?

Real Life Examples • DDT is a pesticide used to kill mosquitos and agricultural pests • DDT was sprayed in the 1940’s and 1950’s

• DDT traveled from the bottom of the food chain and increased in concentration Grasshopper Shrew Hawk

Result of DDT • Due to the biomagnification of DDT, large predatory birds like Bald Eagles, have high concentrations of DDT • The DDT caused these birds to lay eggs with thin shells • Predatory Bird populations dropped significantly, and some almost went extinct

Other Real Life Examples • Water has been polluted with Mercury and PCB’s (polychlorinated biphenyl) • Both chemicals are carcinogenic (cancer causing) • They can cause neurological issues, infertility, and deformities • PCB’s are what is found in the Hudson River

Where is the greatest amount of pesticide? Even though there are Key: less organisms Dots equal at the top of a food Pesticide chain/web the concentration of a toxin is greater at the top than at the bottom

Bald Eagle Video