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Biomagnification. Biology. When we try to pick out anything by itself, we find it hitched to everything else in the universe. John Muir. Biomagnification. Definition:
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Biomagnification Biology
When we try to pick out anything by itself, we find it hitched to everything else in the universe. John Muir
Biomagnification • Definition: • Biomagnification, also known as bioamplification, or biological magnification is the increase in concentration of a substance, such as the pesticide DDT, that occurs in a food chain
Energy Available to Consumers at Next Trophic Level Energy Lost by Death and Decay Energy Lost by Respiration Energy Lost by Excretion Energy Lost by Egestion of Feces Energy Ingested
Food Chain Example • Let’s look at our food chain to see how biomagnification works:
Food Chain • Let’s say, for example, that each piece of plant material has one microscopic drop of methyl mercury.
Food Chain • One insect eats 25 pieces of plant material, that would mean that each insect would have _______ microscopic drops of methyl mercury in its body.
Food Chain • If one small fish needs 10 insects to live, then one fish would have _____ microscopic drops of methyl mercury.
Food Chain • One big fish eats 5 small fish to live. So, one big fish would collect a total of _____ microscopic drops of methyl mercury in its body.
Food Chain • What about you and me? Lets say we eat 1 big fish a day for 3 days. We would collect total of ______ drops of methyl mercury in our body over the 3 days. This is how biomagnification works!
Food Chain • Now let’s say that methyl mercury makes living things sick. The more methyl mercury in the living organism, the more sick it would get. From our example above, which organism will be most affected by the toxin methyl mercury?
Peregrine Falcon • The Peregrine Falcon became an endangered species because of the overuse of pesticides such as DDT during the 1950s, 60s, and 70s. Pesticide biomagnification interfered with reproduction, thinning eggshells and reducing the number of eggs that survived to hatching. The organochlorine build-up in the falcon's fat tissues resulted in less calcium in the eggshells, leading to more fragile eggs. In several parts of the world, such as the eastern USA and Belgium, this species became extinct as a result.
Bald Eagle • Once a common sight in much of the continent, the Bald Eagle was severely affected in the mid-20th century by a variety of factors, among them thinning of egg shells, attributed to the use of the pesticide DDT. DDT itself was not lethal to the adult bird, but it interfered with the bird's calcium metabolism, making the bird either sterile or unable to lay healthy eggs. Female eagles laid eggs that were too brittle to withstand the weight of a adult.
Pesticide Resistance In the beginning, most pests were sensitive to DDT but a few were resistant The resistant forms survived and reproduced In the end, most pests were resistant to DDT
Horton, in Dr. Seuss’s Horton Hears a Who • “We’ve GOT to make noise in greater amounts! So, open your mouth, lad! For every voice counts!”
