Predator Prey

Age

Elementary School

Format

Hands-on

Materials

   White poster board
   Red, blue, white poker chips
   Modified goggles
   Stopwatch 

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. Always supervise students very carefully during interactive demonstrations. Assist children in putting on the goggles and be careful that they are not too tight.

Preparation

Put the white poster board on the table, and scatter the poker chips over the board. Make sure there are an even number, approximately ten of each color poker chip.

Demonstration

1) Place white poster board on the table

2) Spread an even number of red, blue, and white poker chips over the white poster board

3) Ask student to collect as many poker chips as they can during alloted time

4) Time student for fifteen seconds

5) Count the number of poker chips collected with the student

6) Ask questions about the science behind this demo

What to Say

This game deals with predator/prey interactions in nature. Do you know the difference between a predator and prey?

A predator hunts for prey, so it can eat it.

Can you put these goggles on for me? (Hand goggles to student) Now pick up as many chips as you can in fifteen seconds, and hold them in your hand. Ready? (Begin timing student) Go!

Now let's see which ones you were able to get. It looks like you got more red and blue chips than white ones. Why do you think that is?

You just demonstrated a principle of natural selection.

Imagine that you are a hawk, and you are flying over a field. You think you see a mouse scurrying across the ground, but it's hard to see because the mouse blends in to its surroundings; the grass, the dirt, the weeds. This mouse is like our white poker chips, which blend in with their white background. Now imagine that you see a bright red mouse. It will stand out more, and it will be easier to catch. Since it is easier for the hawk to see the red mice, the hawk will catch more of them and the ones that blend in better will survive the hunt. This also means that there will be more white mice left to reproduce, and there will be more white mice over time.

This is natural selection because the prey's color determined which ones survived.

Why It Is

Animals that are able to blend into their environments are less likely to be spotted by predators and eaten. This means that the population will shift to having more camouflaged animals surviving, and those animals will have a greater chance of reproducing. Because of this shift, the future generation will have more camouflaged animals.

Real Life Examples

Peppered moth population changing from a lighter color to a darker color during the Industrial Revolution in Britain

Antibiotic resistance in microbes

Sickle cell anemia more common in countries where malaria is a threat