Biomagnification and the Trouble with Toxins

Biomagnification and the Trouble with Toxins

Captions are on! To turn off, click CC button at bottom right. Follow us on Twitter (@AmoebaSisters) and Facebook! Have you ever heard the song “Big Yellow
Taxi?” It’s one of our favorites. It was originally written and recorded by
Joni Mitchell back in the seventies, and there are lots of singers who have their own recordings
of her song. Great song. The song has this verse in it that asks “farmers
to put away their DDT.” You know when you’re young and you don’t
understand a lyric in a song—you kind of—make up what that might mean in your head? ….Ok maybe that’s just us. We didn’t really get that lyric until we
got older— now we do—and it’s so much more powerful now. So of course, it deals with science. DDT is a chemical pesticide, and it is called
DDT because it stands for this. Yeah…so we’re going to call it DDT. Its use really sparked in the 1940’s as
a powerful chemical pesticide—meaning it was used to kill insect pests. Often the types of insect pests that destroy
crops so it was popular in agriculture. DDT was very popular. But DDT soon came under some scrutiny. It became evident that pesticide was having
negative environmental effects. In 1972, the EPA issued a cancellation order
of DDT and the EPA still works with other countries to control substances such as DDT
and similar chemicals. DDT is used in other parts of the world, such
as areas that are battling malaria and therefore looking for mosquito control options with
indoor residual spraying. It is definitely far more regulated and controlled
in its use today. One thing that DDT really taught us is that
the effects went far beyond the little insects that it may be targeting. Some high level consumers, such as bald eagles
for example, really took a bad hit from DDT. For bald eagles, this affected reproductive
abilities, including severe thinning of bald eagle egg shells. But why? After all, bald eagles do not typically eat
the small insects that the DDT targeted. This takes us into our topic of biomagnification. And biomagnification doesn’t just involve
DDT. There are many chemicals and toxins that can
be biomagnified. Mercury is another example that you may hear
about. When you think of anything being magnified,
you think of it getting bigger. Biomagnification describes what happens when
toxins become more and more concentrated in the living tissues of organisms as you go
up in the food chain. But why does this happen? Take a look at these little bugs here. Imagine that perhaps these insects have been
poisoned. Here are some still living poisoned insects. Weakened, some may make easy targets for predators. This poison is killing off a lot of the insects
but not all of them. Each of these insects will contain one triangle,
which represents a concentration of that toxin. Now imagine these insects are eaten by secondary
consumers such as lizards or rodents. As those secondary consumers eat those insects,
the toxin concentration level increases in the secondary consumers. Why? Well recall in the energy pyramid, that organisms
only keeps 10% of the energy from the trophic level below. The remaining is lost as heat or undigested. That means that as you move up trophic levels,
the animals will have to consume far more biomass from the level below to be able to
compensate for this and survive. And everything it consumes from that trophic
level below could have that toxin stored in its tissues—which now, is an unwanted gift. It’s adding up. Now if a predatory bird begins to eat these
secondary consumers, this concentration further increases. Remember it only gets 10% of the energy from
the trophic level below—-and so as a tertiary consumer—-it must eat a significant amount
of secondary consumer biomass to survive. Increasing toxin concentration in the tissues! The problem with many toxins or chemicals
is that if they are not controlled well, they can get into the air, the soil, the water. With DDT, it was able to get into the water
supply. Primary consumers, such as small fish, began
to feed on those producers. The concentration in body tissues of the poison
in the primary consumers increased due to biomagnification. Secondary consumers, such as larger fish,
feed on those primary consumers. The concentration in body tissues of the poison
in the secondary consumers increased due to biomagnification. Tertiary consumers, such as bald eagles, feed
on the secondary consumers. The concentration in body tissues of the poison
in tertiary consumers increased due to biomagnification. In summary, biomagniciation is a major factor
to consider for any pesticide or chemical toxin that humans may make. We need people like you to come up with new
solutions! If you take a look at the end of our virus
video, you can learn about a virus that has been used as a pesticide as it only attacks
specific types of pest insects. What if viruses were manipulated to attack
specific pests to avoid the use of toxin? But even then, could there be consequences
for taking out specific types of pest insects? One last thing to mention. Animals face additional problems such as habitat
destruction, habitat loss, and poaching. There are ecologists who devote their lives
to helping these organisms and raising awareness among people like you. Truly, a career for the brave and bold. That’s it for the amoeba sisters and we
remind you to stay curious!

78 thoughts on “Biomagnification and the Trouble with Toxins

  1. Hi AmoebaSisters,

    I really like your educational video, but I was hoping you would made something beyond school syllabus video like Kurtzgessat channel, but concentrated in biology

    -Bored Engineering Student

  2. very good recommended to all students very good 10/10 would watch again.

    Lol, but in all seriousness, I advise anyone to watch this.

  3. Great video! The natural consequence of this info is for humans to eat lower on the food to reduce the pesticide load we get from food along with things like heavy metals, dioxins, perfluorochemicals, flame retardants and other pollutants!

  4. Really, really love your videos.
    I'm chemist but i love all science, that includes biology. So, i really learn a lot from topics i dont know of biology.

  5. You should mention how it affects us. We are not all Americans so can't relate to how much you need to talk about bald eagles :p (I have been looking for a while for a good video and this one is fantastic!) Really easy to follow, thanks ladies

  6. thankyou sososos much, ive watched neaarly all your videos and you might as well be the reason i pass science. you explain ssososso well and you are literally AMAZING at what you do!!!!!!!!!!!!!!!!!!!!!!!!!!!!1 thankkyyouuuuuu ssososososoos muccchhhhh, i couldnt be more gratefull <33


  8. I'm sharing this on social media because it is easier than attempting to explain to people what is wrong with DDT. I doubt they will watch it.

  9. Hello. I am conducting a biology experiment that focuses on the decomposition rate of fast food fries vs. homemade. The only problem is.. I don't really know how to measure the rate of decomposition. Any ideas? Anything helps!

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