Download Variation and Survival - Richland Elementary School

Variation and Survival
Natural Selection is the survival and reproduction of those organisms with the best
adaptation to their environment. To better understand how natural selection works, why
not try this activity about camouflage, or the ability of organisms to blend in with their
environment and hide from predators.
Problem: How does variation affect survival?
Procedure:
1. One member of your group is a predator. Hold the forceps and stand at end of table.
Look at me away from table.
2. Other members put a piece of newspaper down on table. This is a gray bark tree.
Spread your moths out.
3. When I say go the predator has 10 seconds to pick up as many moths as possible.
4. Record the number of each type of moth eaten.
5. Another member now is the predator. Repeat. Record
6. Now the environment has changed and trees are covered with soot and bark is black.
Spread out black construction paper. Place moths down.
7. Another member is now the predator. Ready. Record.
8. Repeat with your last predator. Record.
Trial
Gray Tree Trunk (newspaper)
Black
Newsprint
White
moth
moth
moth
Black tree trunk (construction)
Black
Newsprint
White
moth
moth
month
1
2
Analzye:
1. Which variation of moth was eaten most on gray tree trunks?
2. If we repeated this for more generations which type of moth would you predict to
survive and reproduce?
3. Which type of moth would you predict would not be able to reproduce and may go
extinct?
4. Which variation of moth was eaten most on black tree trunks?
5. Which type of moth would survive and reproduce? And which type of moth would go
extinct?
6. How did variation affect the survival of these moths?
7. How did the natural environment affect the survival of these moths.
8. What is an adaptation?
Natural Selection
Darwin’s theory of natural selection states that helpful variations may gradually
accumulate in a species and over a long period of time the species will change.
Problem: How does competition contribute to natural selection?
Procedure:
1. You are a species of birds which has variation. Describe your beak variation.
A. tubies
B. spooners
C. choppers
D. forcepies
2. You each must compete over a limited amount of food. Ready. Count the number of
pieces of food you were able to pick up. I will record.
3. Some of you will reproduce and some of you will die. Get your new beaks. Compete
again.
4. Repeat for 5 generations.
Analyze: Graph the results.
Conclude:
1. Which variation decreased in number?
2. Which variation increased in number?
3. Why did some species become extinct?
4. Explain how the environment (amount of food) determined which organisms
would survive and reproduce?
5. How did this activity simulate (pretend) natural selection?
Period 1
Generation
tubies
spooners
Choppers
Forcepies
1
8
8
8
8
2
2
12
2
16
3
0
6
2
24
4
0
5
Period 2
Generation
tubies
spooners
Choppers
Forcepies
1
8
8
8
8
2
4
6
8
14
3
2
6
8
16
4
2
6
8
16
5
0
6
4
22