The Process of Natural Selection

Name ______Date ______Pd ______The Process of Natural Selection Introduction: What does “survival of the fittest” really mean? The problem with visualizing evolution is that it generally occurs over periods of time much longer than we can even imagine. How many years back would we have to go to see 50 generations of your family? In this activity, we will watch a population of blue organisms (that we’ll call Smorfs) evolve over a period of fifty generations.

Procedures: 1. Google the phrase Evolution Lab to find http://www.biologyinmotion.com/evol/index.html. 2. Let’s quickly review the Evolution Lab and Natural Selection pages to complete the matching section. a) Struggle for Existence ● Fish get their fin size and color from their parents

b) Individual Variation in Phenotype ● One fish has a fin that is abnormally small

c) Inheritance ● One day, all fish will have large fins

d) Some Phenotypes are Better Adapted● Larger fins are better for swimming than smaller fins

e) Consequently, Species Evolve ● Many fish eggs are laid and only a few hatch

3. What is natural selection?

4. Our activity begins on the third page - Introduction to the Simulation. Let’s read this section and then answer the following questions. a) How do the hungry Smorfs eat?

b) What two things happen after the Smorf eats?

c) What is the only variation among the Smorf population?

d) How does this variation occur?

5. On the next page there are many different measurements and options but we only focus on a few. a) How many squares high can each of the Smorfs reach?

b) Where is the hunger meter for each Smorf?

c) What is the mutation rate? (Set it at 0.2)

d) How many mutations have taken place so far? 6. Let’s watch the changes over the first five generations of Smorfs.

Current 1 2 3 4 5 Cycle Mean Phenotype

a) Can a species change dramatically after five generations?

b) How frequently do mutations occur within a population?

c) How would you describe the typical offspring of each Smorf?

d) Were there more mutations that increased or decreased grabber length?

e) Were there more Smorfs with increased or decreased grabber length?

f) Why don’t the Smorfs with a shorter reach influence the population?

g) Will there ever be a time when all Smorfs have a grabber length of four?

h) Explain how the length of the Smorf’s grabber and the length of a giraffe’s neck are similar.

i) How did this simulation illustrate the process of natural selection?