Biology lab microevolution

Biology 110 Online Evolution lab

Student Directions:

1.    Go to http://www.sasinschool.com/login

2.    In the Quick Launch box (will have QL# inside) on the upper right corner of the screen, enter: 4

3.    When prompted by the popup enter the username: located5questions (it’s weird, but no password is needed with this login). If you have pop-ups blocked you will have to allow pop-ups from SAS Curriculum (when I work in Chrome, a little red x appears at the end of the URL address box—I click on the x and am allowed the option of “always allow pop-ups from SAS Curriculum…). The program requires Java and maybe additional add-ons. Be sure to “allow” these in order to get the simulation to run.

4.    Clicking on the “Getting Started” tab will provide the information provided below. Be sure to read through this information prior to beginning.

5.    Clicking on the “data and observations” tab will provide the same information that I’ve included below. No need to print again. You will need to follow the directions and answer these questions as you go through the simulation.

6.    Clicking on the “analysis and conclusions” will also provide the same information as I’ve provided below after the “data and observations section”.  Type your answers in as you proceed through this section.

7.    Ready to begin? Read the “About the Topic” section and proceed through the rest of the lab. Once you have completed each section, don’t forget to save the document with your name in the file name. Submit on Moodle!

 

About the Topic

Sources Of Genetic Variability

Genetic variations provide the raw material for evolution. These variations come from two sources:1. mutations that produce different alleles, and 2. sexual reproduction, in which alleles from parents segregate and recombine in offspring.

Evolution

Biological evolution involves genetic changes in a group of organisms. These changes occur on two levels:macroevolution (the grand scale), and microevolution (the small scale). On the “macro” scale of evolution, different species arise, live for a while, and then pass into extinction as new species arise to replace them (over thousands or millions of years). Microevolution involves small-scale changes within a single species. This occurs as populations respond to their own unique circumstances over a period of a few generations. Given enough time, microevolution can lead to macroevolution.

Populations Evolve, Not Individuals

Because an individual’s genes are determined at conception, individuals can’t evolve. But individuals are part of a population that may change over time. Some individuals have genotypes that are preferentially suited for survival. These individuals tend to produce more offspring. Thus, a larger proportion of their alleles is passed down to succeeding generations. Over time, the proportion of “good” alleles within the population increases and the “less good” alleles decrease. (However, note that some traits are neither “good” or “bad” and have no bearing on an organisms ability to survive and/or reproduce and frequencies of those alleles may or may not change over time.)

By examining many generations of a population and the frequency of each genotype, scientists can determine if the population is evolving. If the proportions of the different genotypes change, evolution is occurring. If the genotypes do not change, the population is not evolving.

 

 

About the Simulation

A.     Butterfly Color Slider: sets the number of red and yellow butterflies in the founding population

B.     Mutation/No Mutation: selects whether or not to introduce a mutation into the founding population

C.     Mate: mates the founding population to establish the first generation of butterflies

A.     Flower Color Buttons: turn the red, orange, and yellow flowers on and off

B.     None: indicates no predator is introduced

C.     Sight-Based: introduces a predator that hunts by sight

D.    Smell-Based: introduces a predator that hunts by smell

E.     Mate: mates the current generation of butterflies

F.     Eat: allows you to select and eat butterflies (using your mouse)

G.    Butterfly Population: displays the generation number and the current butterfly count for each color

H.    Audio On/Off: turns the audio on and off

I.      Restart: resets the simulation and launches the Establish Population panel

·The simulation allows you to track the genotypic frequencies of variants of a gene, C, which determines color in a population of butterflies across several generations. There are three alleles for the C gene: C^R, which specifies red; C^Y, which specifies yellow; and C^B, a new mutation, which specifies blue. Shuffling and recombining these alleles during sexual reproduction can result in six different genotypes.

·The ratio of each color can be used to calculate the genotypic frequency (you will be calculating genotypic frequency and including in your tables for each generation) for the genotype that specifies that color. Because C^B is dominant, a blue butterfly could have any one of three different genotypes. For the purposes of this activity, consider all of the blue butterflies together as a single “blue” genotype and calculate frequency for “blue.” Genotypic frequencies are numbers between 0 and 1 and the frequencies for each generation always add up to 1.

·Clicking the Mate button allows the butterflies remaining on Butterfly Island to mate and produce the next generation. Choice of mates is always random and no butterflies from the previous generation survive into subsequent generations.

·Always reestablish your population to generation 1 by clicking the Restart and Mate buttons before starting a new experiment and making any changes to the environment.

 

Data & Observations

Part I: Explore Butterfly Island

Two groups of butterflies, one exclusively red (C^RC^R) and one exclusively yellow (C^YC^Y), have recently colonized a small flower-covered island and begun to interbreed. Use the simulation to investigate the evolution of this new butterfly population under different genetic and environmental conditions.

A.     Establish your population. The default values for red and yellow parents are set to 10 of each color. Leave the settings at the default values unless otherwise instructed. (Use the slider to change the settings.) 

1.   Record the numbers of red and yellow parents in the General Conditions box (found in the Data Collection area with the data tables below Question #14).

B.     Choose no mutation. Click the Mate button to allow the parents to mate and produce the first generation of offspring.

C.     Examine the image of Butterfly Island and answer the following questions: 

2.     What colors are the flowers? Do the colors you see correspond to those selected in Box 1 of the Settings panel at the top of the simulation? Explain.

 

3.     What colors are the butterflies?

 

4.     List the genotypes of each color butterfly Use C^R for the red allele and C^Y for the yellow allele. (Remember that there are two alleles in every genotype.)

 

A.    Yellow Butterfly Genotype:

B.     Red Butterfly Genotype:

C.     Orange Butterfly Genotype:

 

5.     If you see colors other than the red and yellow that you started with, explain where the additional colors came from. (Hint: Use a Punnett square for each potential set of parents to help you answer this question.)

 

6.     Pick and count all of the butterflies of one color. Does your count match the amount listed in the Results panel at the bottom of the simulation?

 

7.     Do the different-colored butterflies show any preferences for the flowers? For example, do red butterflies perch only on red flowers?

 

D.    Click the Off button for the red flowers in Box 1 of the Settings panel. 

8.     Describe what happened to the clusters of red flowers.

 

9.     Did you observe any changes to the other clusters of flowers? Explain.

 

10.  Was there any change in the butterflies?

 

E.     Restore the red flowers by clicking the On button for the red flowers. Click the Off buttons for the orange flowers and for the yellow flowers in Box 1 of the Settings panel. 

 

11.  What happened to the orange and yellow flowers?

 

12.  Can you turn the blue flowers off?

 

13.  Did the butterflies change?

 

F.   Click the On buttons to restore all of the flower colors.

G.  Click Restart, at the lower right side of the simulation, to bring back the Establish Population window.

 

Part II: Experiments and Data Collection

You will perform ten experiments to investigate the effects of different genetic and environmental conditions on the evolution of your butterfly population. To carry out these experiments, you will use one of the two procedures listed below as directed for each experiment. These procedures are identical except that Procedure 2 introduces a predator. By running identical tests, altering only one condition at a time, you will be able to determine the effects each condition has on the evolution of your population. Be sure to record your data at each generation in the data tables provided below. Each table includes the information for the experiment parameters that are to be followed.

 

Procedure 1: Use for Experiments 1, 2, 3, and 8

 

 

Procedure 2: Use for Experiments 4, 5, 6, 7, 9, and 10

H.    Carry out ten experiments, using the conditions described below and either Procedure 1 or Procedure 2 (as indicated for each experiment), to investigate the effects of genetic and environmental conditions on the evolution of your butterfly population. Be sure to record observations for each generation as directed in the tables provided. 

14.  For experiments 2, 5, and 7, be sure to delete the same two flower colors. Record the deleted colors in the General Conditions table provided below and in the title for Tables 2, 5, and 7.

 

Specific Experimental Conditions for Investigating Evolution of the Population of Butterflies on Butterfly Island

 

 

 

 

 

 

 

 

 

 

 

Data Collection

Be sure to complete all fields in each table. Do to expected differences in responses I did not “lock” or prevent tables from breaking across pages. If your table runs over to the next page, don’t forget to fill in all of the cells!

 

General Conditions

Parental Ratios Red (CRCR): Yellow (CYCY)

__________: __________

Eliminated Colors (Experiments 2, 5, and 7)

 

Table 1: Experiment 1 (Procedure 1, no mutation, all colors on, no predator)

*Instructions for completing the genotypic frequencies (requested for each genotype for each generation [what goes in shaded cells]) are at the beginning of the next section. Feel free to collect data on all ten experiments and then come back to each and fill in genotypic frequencies.

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5

 

 

 

Table 2: Experiment 2 (Procedure 1, no mutation, _______ colors deleted, no predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5

 

 

Table 3: Experiment 3 (Procedure 1, no mutation, no colors on, no predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5

 

Table 4: Experiment 4 (Procedure 2, no mutation, all colors on, sight-based predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any changes to the buttons in box 3.
Describe any other changes to the butterflies.

 

Table 5: Experiment 5 (Procedure 2, no mutation, _________ colors deleted, sight-based predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any other changes to the butterflies.

 

Table 6: Experiment 6 (Procedure 2, no mutation, all colors on, smell-based predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any other changes to the simulation/butterflies.

 

Table 7: Experiment 7 (Procedure 2, no mutation, _______ colors deleted, smell-based predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any other changes to the simulation/butterflies.

 

Table 8: Experiment 8 (Procedure 1, blue mutation, no colors on, no predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any other changes to the butterflies.

 

Table 9: Experiment 9 (Procedure 2, blue mutation, no colors on, sight-based predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any other changes to the butterflies.

 

Table 10: Experiment 10 (Procedure 2, blue mutation, no colors on, smell-based predator)

Generation	Number of Butterflies
	Genotypic Frequency
	Red (CRCR)	Orange (CRCY)	Yellow (CYCY)	Blue
1
2
3
4
5
Describe any other changes to the simulation/butterflies.

 

Analysis and Conclusions

Data Analysis

1.     For experiments 1-10, use the following formula to determine the genotopic frequencies of each color in each generation. (Remember, the total population size remains constant at 20.)   

Record the genotypic frequencies as decimals in the shaded boxes in Tables 1-10.

2. Compare the 1^st generation genotypic frequencies from the plots for experiments 1-7 and for experiments 8-10. Do the frequencies of each color change from experiment to experiment or do they remain the same?

Environmental Factors and Evolution

3.  Examine Table 1. Did the frequency of each color of butterfly change after 5 generations? Recall the definition for evolution. What do the results in Table 1 tell you about your population?

 

4.     Compare Tables 1, 2, and 3. Describe and explain the effect of the loss of red, orange, and yellow flowers on the frequency of red, orange and yellow butterflies.

 

 

5.     Compare Tables 1, 4, and 6. Describe and explain any differences among the tables resulting from the actions of the predators.

 

6.     Compare Tables 1, 2, 4, and 5. Describe and explain any differences among the data resulting from the combination of the action of the sight-based predator with the loss of two of the flower colors.

 

 

7.     Compare Tables 2, 6, and 7. Repeat the above step in Question 6, but this time for the smell-based predator and the loss of two flower colors.

 

8.     What effect might you expect the predators to have on the butterflies if all but the blue flowers were removed?

 

 

Genetic Factors and Evolution

1. Examine Tables 3, 8, 9, and 10. Describe and explain any differences among the tables resulting from the combined effects of the mutation, the predators, and the loss of all flowers but the blue flowers. Recall your answer to question 9. Discuss the potential value of the blue mutation to your population. Would all mutations be expected to have a similar effect? Explain.

 

Conclusions

Answer the following questions based on the data you collected and analyzed.

1. Did your population evolve in any of the experiments? Explain.

 

1. If the population evolved, was there a single genetic or environmental factor that allowed evolution to occur or did evolution require multiple factors? Explain.

 

 

Applying What You Have Learned

A gene in snapdragons determines whether the flowers will be red (genotype RR), white (genotype rr), or pink (genotype Rr). A garden club has planted a garden of snapdragon plants. The garden contains 9 red, 42 pink, and 49 white plants.

12.  What are the initial frequencies of each color of plant? The plants are allowed to mate randomly and produce the first generation of offspring

 

The plants are allowed to mate randomly and produce the first generation of offspring.

13.  What colors will be found in the first generation?

 

14.  Assuming no selection or mutations occurred, what frequencies would you expect for each of these colors in this generation?

 

 

15.  If you assume that there were 300 plants in this generation, how many plants of each color would there be in the garden?

 

A family of rabbits selectively eats all of the white plants before the plants can reproduce. The surviving plants from the first generation are allowed to mate randomly and produce the second generation of offspring.

1. Using Punnett squares, predict the flower colors that you would expect to see in the second generation.

 

 

1. If the rabbits continue to eat only the white plants, predict what would happen to the snapdragons over the course of succeeding generations.