Biomagnification: Difference between revisions

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== Age ==
{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Biology]]:
| Biomagnification
|-
| Grade Range:
| [[Elementary School]], [[Middle School]], [[High School]]
|-
| Format:
| [[Stage]]
|}


Elementary School, Middle School, High School
This demonstration works well for small groups of students, since it is possible to have all of them involved in the demonstration. Be sure to collect the marbles at the end!
 
== Format ==
 
Stage, Hands-on


== Materials ==
== Materials ==


    Plastic cup
* 12-27 Small (2-4 oz) Cups
    Red marbles
* 4-9 Mid-size 6-8 oz Cups
    Clear marbles (in biomagnification box)  
* 2-3 Large (12-16 oz) Cups
* Clear Marbles
* Red Marbles


== Safety Precautions ==
== Safety Precautions ==


Science Theatre demonstrators must keep the safety of themselves and their audience in mind at all times. All Science Theatre demonstrators must have read through the Safety Training page. The ST Safety Box with first aid kit, fire extinguisher, etc. should always be available to demonstrators. Always wear safety gloves, glasses, and a labcoat if handling chemicals; always perform potentially dangerous demonstrations at a safe distance from the audience; and always keep a very close eye on any volunteers you call from the audience. Don’t let small children (or large children, or small or large adults) eat the marbles.
Please read the General Safety section of the [[Demonstration Safety]] page before performing this demonstration.
 
== Preparation ==
 
Set up enough cups for children participating in the demonstration, designate most of the kids to be minnows, some kids to be fish, and only one to be the shark. The minnow cups should have a few red marbles and one or two clear marbles. Fish and sharks only get a few clear marbles.


== Demonstration ==
== Demonstration ==
;Preparation: Prepare the small cups for the demonstration: Fill two thirds of the small cups with 5 clear marbles. The last third should get four of the clear marbles, and one of the red marbles.
;Presentation:
# Split the students into three groups. The first group will have two thirds of the students, the second group will only have two or three students, and the remaining students will make the third group. This demonstration works best with a total number of students between 18 and 40, but can be adjusted appropriately for smaller (or bigger) groups.
# Give each student in the first group a small cup of marbles, and have them start to wander around in a large group. Give the second group the large cups, and give the third group the mid-size cups.
# Explain to the audience that the first group represents minnows, the third group represents average-size fish, such as carp, and the second group represents the big fish, such as pike. Some of the minnows have ingested toxins, represented by their red marbles, but they aren't noticeably affected by them. Ask all the minnows to hide their marbles by putting a hand over the top of their cup, so that nobody can see who has a colored marble.
# Have the carp group now come in and "eat" minnows by taking the minnow's cup of marbles and pouring them into their own cup. Each carp can only eat a max of three minnows. When a minnow is eaten, they give their cup back to the presenter and return to their seat. If a carp has two red marbles, then it cannot eat anymore because it is "sick". A carp cannot choose to not eat a minnow; They have to take the marbles of any minnows they get.
# Look at the carp cups. Do any of them have two red marbles? Now have the carp hide their marbles by putting a hand over the top of their cups.
# Now have the pike group come and "eat" the carp by taking the carp's cup of marbles and pouring them into their own cups. Each pike can only eat two or three of the carp, depending on the carp-to-pike ratio. If a Pike ends up with three or more red marbles, then they become "sick" and cannot eat anymore.
# Look at the pike cups. How many of them were sick? If any of them have more than three, then they "die" from the toxins. Did any die? Collect all materials from the students and have them return to their seats before giving the explanation.


Start out by showing each cup. Only the minnows have been contaminated (it could be from mercury or something similar in the water) and contain clear marbles. Everyone else only has red (uncontaminated) marbles.
Spell out the rules. Minnows just swim around. Fish eat minnows, and sharks eat fish. To eat someone else, you just take the marbles from their cup.
Allow kids to eat each other
Once the shark is the only one left alive, show everyone what is in his cup. One or two clear marbles are okay, and the fish can survive, but the shark will have a lot more than one or two. Explain how this works in real life, and introduce the term biomagnification.
== What to Say ==
Has anyone ever heard the word “biomagnification?” It’s what happens when we pollute our environment, and can be very bad for us! We have a demonstration today that will teach all of us what biomagnification means! (If this is a stage show, ask for volunteers; otherwise assign roles to each kid. You should have one shark, at least two fish, and four minnows. Any number of kids should work; just try to arrange it so that there are a lot of minnows and a few fish and one shark.)
After they complete the activity, show them the contents of the shark’s cup (they should have all the marbles.) Explain that while one clear marble is not toxic, this many are. The shark would probably die because of the high concentration of toxins. Explain how this is very common with mercury in our water, and other environmental pollutants. That’s why it’s so important that we don’t pollute! We may end up eating an animal that has a large buildup of toxins.


== Why It Is ==
== Why This Works ==


Because predators often eat more than one animal, if a toxin cannot be removed from the body naturally, it will build up. If they continue eating animals that are contaminated (or worse, animals that have eaten animals that are contaminated) they may accumulate a very high amount of toxins.
''Biomagnification'' is when a substance, such as a toxin, is found in greater concentrations in organisms as you go up the food chain. Organisms at the bottom of the food chain typically are the first to eat the toxic substances, but because they individually ingest only small amounts, the effects of the toxin are not easy to spot or distinguish. When those organisms are eaten by something above them in the food chain, the toxins will collect in the larger organism, which can cause it to become ill. When those organisms are eaten by things above them in the food chain, the toxins continue to build up, and those animals toward the top of the food chain can suffer the most because of the buildup of toxins. The buildup can even result in the deaths of those animals at the top of the food chain, which can cause it to collapse. This is why pollution is bad, since the chemicals we put into the environment will eventually result in severe or even total destruction of the food chain.


== Real Life Examples ==
== Additional Information ==


Mercury and other heavy metals, DDT (see Rachel Carson’s Silent Spring) All of these have been found to accumulate in organisms and then have the potential to biomagnify.
* This demonstration pairs well with the [[Food Chain Jenga]] demonstration.
* Feel free to use other example animals instead of (minnows/carp/pike), such as (frogs/snakes/hawks) or (grass/deer/bears)

Latest revision as of 19:48, 16 May 2016

Biology: Biomagnification
Grade Range: Elementary School, Middle School, High School
Format: Stage

This demonstration works well for small groups of students, since it is possible to have all of them involved in the demonstration. Be sure to collect the marbles at the end!

Materials

  • 12-27 Small (2-4 oz) Cups
  • 4-9 Mid-size 6-8 oz Cups
  • 2-3 Large (12-16 oz) Cups
  • Clear Marbles
  • Red Marbles

Safety Precautions

Please read the General Safety section of the Demonstration Safety page before performing this demonstration.

Demonstration

Preparation
Prepare the small cups for the demonstration: Fill two thirds of the small cups with 5 clear marbles. The last third should get four of the clear marbles, and one of the red marbles.
Presentation
  1. Split the students into three groups. The first group will have two thirds of the students, the second group will only have two or three students, and the remaining students will make the third group. This demonstration works best with a total number of students between 18 and 40, but can be adjusted appropriately for smaller (or bigger) groups.
  2. Give each student in the first group a small cup of marbles, and have them start to wander around in a large group. Give the second group the large cups, and give the third group the mid-size cups.
  3. Explain to the audience that the first group represents minnows, the third group represents average-size fish, such as carp, and the second group represents the big fish, such as pike. Some of the minnows have ingested toxins, represented by their red marbles, but they aren't noticeably affected by them. Ask all the minnows to hide their marbles by putting a hand over the top of their cup, so that nobody can see who has a colored marble.
  4. Have the carp group now come in and "eat" minnows by taking the minnow's cup of marbles and pouring them into their own cup. Each carp can only eat a max of three minnows. When a minnow is eaten, they give their cup back to the presenter and return to their seat. If a carp has two red marbles, then it cannot eat anymore because it is "sick". A carp cannot choose to not eat a minnow; They have to take the marbles of any minnows they get.
  5. Look at the carp cups. Do any of them have two red marbles? Now have the carp hide their marbles by putting a hand over the top of their cups.
  6. Now have the pike group come and "eat" the carp by taking the carp's cup of marbles and pouring them into their own cups. Each pike can only eat two or three of the carp, depending on the carp-to-pike ratio. If a Pike ends up with three or more red marbles, then they become "sick" and cannot eat anymore.
  7. Look at the pike cups. How many of them were sick? If any of them have more than three, then they "die" from the toxins. Did any die? Collect all materials from the students and have them return to their seats before giving the explanation.


Why This Works

Biomagnification is when a substance, such as a toxin, is found in greater concentrations in organisms as you go up the food chain. Organisms at the bottom of the food chain typically are the first to eat the toxic substances, but because they individually ingest only small amounts, the effects of the toxin are not easy to spot or distinguish. When those organisms are eaten by something above them in the food chain, the toxins will collect in the larger organism, which can cause it to become ill. When those organisms are eaten by things above them in the food chain, the toxins continue to build up, and those animals toward the top of the food chain can suffer the most because of the buildup of toxins. The buildup can even result in the deaths of those animals at the top of the food chain, which can cause it to collapse. This is why pollution is bad, since the chemicals we put into the environment will eventually result in severe or even total destruction of the food chain.

Additional Information

  • This demonstration pairs well with the Food Chain Jenga demonstration.
  • Feel free to use other example animals instead of (minnows/carp/pike), such as (frogs/snakes/hawks) or (grass/deer/bears)
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