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 this pyramid, what is happening to the energy? Heat Heat Heat 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 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
Where is the most Mercury? 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 Shrew Grasshopper 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
the concentration of a toxin Where is the greatest amount of pesticide? Even though there are less organisms at the top of a food chain/web the concentration of a toxin is greater at the top than at the bottom Key: Dots equal Pesticide
Bald Eagle Video