Biomagnification

Bioaccumulation Is the accumulation of a specific contaminant in the fat tissues of an organism over time. Which portion of HIPPO does this concept fit into?

Biomagnification Biomagnification occurs when toxins begin to accumulate in body tissues of members of a food chain. The amount increases with the trophic level. How is understanding how contaminants travel from animal to animal important to your life?

Jigsaw Reading Take a moment and get into your jigsaw groups based on the color of your article. Discuss the important information you learned in your section. Answer the review questions in your notes with your group.

Reading Analysis What type of damage can DDT cause to birds?   How does DDT move into lakes, streams and oceans? How is the food web affected by the use of DDT?

DDT DDT (dichloro-diphenyl-trichloroethane) was developed in the 1940’s and was widely used on crops across the United States. It was highly effective in killing agriculture pests and was thought to be safe. that it was used to kill body lice on soldiers during WWI.

Arial crop sprayers were used to spray tons of DDT on crops across the U.S. Main Idea(s) of This Slide – DDT use was widespread across the country, with tons of it used agriculturally as seen in this slide. Photo courtesy of Texas Parks and Wildlife Department

Lets research this DDT Continued In the case of DDT, insects consumed the DDT and built up a level of DDT in their body tissues. Later, when predators ate many insects, they ended up with an even higher concentration of DDT than the insects had. Lets research this

Aquatic Plant The aquatic plants in areas near farming communities were taking in trace amounts of DDT from the water that ran off farmland.

Fish Fish within these bodies of water will consume the aquatic plants. This consumption will lead to passing of DDT from the plants to the fish.

Bald Eagle Once was widely distributed over U.S. As a top carnivore it feeds on fish Swoops down and captures fish off the surface of the water Main Idea(s) of This Slide – The American bald eagle is a top carnivore that once was widely distributed across the U.S. Fish are one of its primary prey items. Photo courtesy of Texas Parks and Wildlife Department

Scientists discovered that DDT was concentrated in the bald eagle DDT affected the eagle’s ability to reproduce Main Idea(s) of This Slide – Because the eagles were the top carnivore in the food chain, DDT became concentrated in their body tissues. The DDT was originally absorbed by the plants on which it was sprayed. It then passed into the body tissues of the insects who consumed the plants. Insectivores (fish) then absorbed the DDT when they ate insects who had DDT in them and had a much higher concentration in their body tissues. Finally, when eagles consumed the fish, they ended up with toxic levels of DDT in their body tissues. The DDT impaired the eagles ability to reproduce. Photos courtesy of Texas Parks and Wildlife Department

Nests contained broken, rotten eggs Scientists found that the eagle eggs had thin egg shells and broke easily Nests contained broken, rotten eggs The number of young produced per breeding pair was reduced Main Idea(s) of This Slide – Scientists discovered that eagles who had built up levels of DDT in their body tissues laid eggs that had very thin shells. The thin-shelled eggs broke easily, causing a much higher mortality of young than was natural.

Population of adult eagles declined to 4,000 and the eagle was listed as “Endangered” Main Idea(s) of This Slide – Over the years of DDT use, the eagle population dropped to approximately 4,000 and the eagle was listed as an “Endangered Species.” Photo courtesy of Texas Parks and Wildlife Department

A day in the life of this food chain Create the food web in your notes We are going to see now a contaminant like DDT progresses through a food web Eagle Fish Aquatic Plants Create a hypothesis about how the contaminant will be accumulated through a food chain

Record the amount of DDT in the aquatic plants, fish, and eagle populations. 125 PPM 25 PPM 5 PPM Each

How does biomagnification correspond (relate) to the transfer of energy throughout an ecosystem and the population of organisms within an ecosystem? Population Energy Eagle Fish Aquatic Plants contaminants

Think-Pair-Share Predict: What would happen to the amount of DDT in the eagles if the amount of DDT in the plants went up? Explain why.   Predict: What would happen to the amount of DDT in the eagles if you were given less fish to eat? Explain why. Predict: What would happen to the amount of DDT in the eagles if there was an increase in the fish population? (think carefully)

Lets see this from a different view.