Download Lab_07_EvoDots Evolution

Biol 160: Lab 7
Lab 7:
Modeling Evolution
OBJECTIVES
•
•
Help you develop an understanding of important factors that affect evolution of a
species.
Demonstrate important biological and environmental selection factors that influence
evolution by natural selection.
MODELING NATURAL SELECTION – EVODOTS
In Darwin’s model of how organisms change over time, he proposed natural selection as the
mechanism of evolution. Evolution takes a LONG, LONG, time. However, we can model years of
natural selection in on the computer by modeling just one of the many types of selective pressures. In
this case, predation is the selective pressure that you will model. Predation is important to evolution
because it places a limit on one of the key requirements of natural selection – the ability of organisms
to survive long enough to reproduce.
In this activity you will model the effects of predation on a prey population. We will be using a
computer model. The different colored dots will represent a variation in a species. You will act as a
predator by clicking on and “eating” the dots.
BASIC DIRECTIONS
HOW TO LAUNCH THE PROGRAM
Log in to computer
Go to Google and enter “Evodots”
Click on the Jon C. Herron Software site.
Scroll down to “Download Evodots 1.1” and click
on “Uncompressed Windows Application”
Click on the Open button, which will launch the
program
Click on the introduction screen to make it
disappear. Now you are ready to use the
program.
STEPS TO RUN EVODOTS
1. Make sure all of the boxes in the bottom right
corner are checked
2. Click on New Population
3. Click on Run
4. Kill 25 dots as fast as you can
5. Click on Stop
6. Click on Reproduce
7. Record Data
8. Repeat steps 3-7 until you have finished 5
generations.
Experiment 1: Natural selection on dots relative to their speed
Before you begin, generate a hypothesis about what you will expect will happen over many
generations. – Do you expect to see an increase, decrease, or no change in the number of fast dots
over many generations of selections. Remember to use If ______ then______ because formats.
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
_______
Biol 160: Lab 7
2. Click on new population. You will see 50 dots in a variation of colors. These colors represent
different speeds. If you click the little arrow in the top right hand corner, it will show you how many of
each color you have. Record in the data table.
Dots vary
in:
Slowest ----------------------------------------------------------------------------- Fastest
Black
Purple
Blue
Green
Yellow
Orange
Red
Start round
1
Start round
2
After
reproduce
Start round
3
After
reproduce
Start Round
4
After
Reproduce
Start Round
5
After
Reproduce
Click “Run” and complete simulation for a total of 5 generations (kill 25 per round, then click
reproduce). Record your data in your data table.
At the end of 5 generations describe your results. Which, if any, of the dots had a better survival rate
than other dots in the 2nd-, 3rd-, and 4th-genration starting populations? Did these differences support
your hypothesis? Has evolution occurred in your dots population? How do you know?
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
____________________________________________________________________
Think of and describe a real-life predator/prey relationship that this experiment might be simulating.
___________________________________________________________________________________________________
___________________________________________________________________________________________________
______________________________________________________________________________________________
Experiment 2: Evolution relative to dot size OR dot visibility
Go to File/options at the top left of the program. Pick either dot size or visibility. This will change the
trait that is variable for your dots. Fill in the data table with your starting population, make sure to
indicate whether you or using dot size or visibility.
Biol 160: Lab 7
Before you begin, generate a hypothesis about what you will expect will happen over many
generations. – Do you expect to see an increase, decrease, or no change in the number of a certain
kind of dots over many generations of selection. Remember to use If ______ then______ because
formats.
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
_______
Dots vary
in:
Black
Purple
Blue
Green
Yellow
Orange
Red
Start round
1
Start round
2
After
reproduce
Start round
3
After
reproduce
Start Round
4
After
Reproduce
Start Round
5
After
Reproduce
Click “Run” and complete simulation for a total of 5 generations (kill 25 per round, then reproduce).
Record your data in your data table.
At the end of 5 generations describe your results. Which, if any, of the dots had a better survival rate
than other dots in the 2nd-, 3rd-, and 4th-genration starting populations? Were there differences in the
frequencies of dots over 5 generations? Did these differences support your hypothesis? Has evolution
occurred in your dots population? How do you know?
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________________________
___________________________________________________________________________________
Think of and describe a real-life predator/prey relationship that this experiment might be simulating.
___________________________________________________________________________________________________
_______________________________________________
Experiment 3: Testing Needed Evolutionary Conditions
At the start of the experiment we made sure the three boxes “variable” “heritable” and “selective”
were checked. In this experiment you will uncheck one of the boxes (click on one the check marks to
see it removed).
Which box did you deselect? __________________________________
Biol 160: Lab 7
How do you think this box being deselected will affect the results of your experiment?
___________________________________________________________________________________________________
_______________________________________________
Run your experiment for 5 generations of selection. Fill in the data table.
Dots vary
in:
Black
Purple
Blue
Green
Yellow
Orange
Red
Start round
1
Start round
2
After
reproduce
Start round
3
After
reproduce
Start Round
4
After
Reproduce
Start Round
5
After
Reproduce
At the end of 5 generations describe your results. Which, if any, of the dots had a better survival rate
than other dots in the 2nd-, 3rd-, and 4th-genration starting populations? Did these differences support
your hypothesis? Has evolution occurred in your dots population? How do you know?
___________________________________________________________________________________________________
___________________________________________________________________________________________________
______________________________