Artifact 3 - Thirsty Birds Script

Artifact 3 - Thirsty Bird Simulation

Gather Materials ahead of time
Need to have fork and spoon cards printed and laminated

Materials

Class data sheet

Activity data sheet 1 and Activity data sheet 2

Fork and Spoon cards

Blue and Gold color cards

Forks (enough for all students)

Spoons (enough for all students)

Plastic cups for “stomachs”

1000ml beakers (1 per every two students)

Large, low containers for beakers (to contain sloshing water)

Liquid (or small pasta such as orzo)

Calculators

Stopwatch

Balance

Pre-lab

What makes something living?  On the board draw the concept map of living things – include those traits identified through consensus in Model 2.

Living things – are diverse, grow, get/use energy, reproduce, are made of cells, respond to their environment.

What have we noticed from looking at different organisms? CREATE LIST WITH STUDENTS

There is great variety in organisms

Shared characteristics

All organisms come from other organisms

What kind of factors might influence the variety of organisms? CREATE LIST WITH STUDENTS

Food, climate, temperature, competition, predation, moisture, homes, sex, time, characteristics of organisms (from parents), evolution, adaptations

Challenge students on the meanings of words such as evolution and adaptation.  If they cannot explain without resorting to a textbook definition (which they cannot elaborate on), ask them to hold off on those ideas until we have a better understanding.

Do these factors affect traits of the organisms?  What type of traits would be affected by the factors?  How would you test these factors?

Have the students come up with answers – note the difficulties in creating experiments with many of the given factors.

Propose doing a simulation in class.  Why?  Because many of the factors change over a long period of time and we only have a couple periods to measure changes.

In our simulation we will examine the relationship between competition for food, mouth parts and bird color.

Instructions

For clarity, walk students through the first couple of rounds.

To expedite the collection of data create the class data sheet on the board, use a document camera, or copy the class data sheet on a transparency.  Have students record their color and mouth parts using hash marks.  

Alternately, if there are an odd number of students assign one student to be recorder or the teacher can be the recorder.

1. Provide the recorder with a class data sheet.
2. If you have multiple classes it is very useful to compile all the classes’ data for analysis.  Trends are more easily seen with greater amounts of data.

Assign each student a color (blue or gold) by giving them 4 cards (4 blue; 2 blue & 2 gold; 4 gold). Distribute color cards to class to attain the following percentages,

• 25%  Blue:  4 blue
• 50%  Gold:  2 blue & 2 gold
• 25%  Gold: 4 gold

On the class data sheet, record the # of students with a particular color.

Assign each student a mouth part by giving them 4 cards (only forks to start).  

On the class data sheet, record the # of students with a particular mouth part.

Have each student mass their stomach and record the amount on the student data sheet.

Each team should fill their 1000mL beaker (food source) with 700mL of water.

Establish feeding rules:  hold stomach in one hand, use mouth part to scoop food into the stomach, no dipping stomach in the food source, no taking food from someone else’s stomach, etc.

Have students feed for 30 sec from the food source.

After 30 sec, determine the mass of the food collected in the stomach by massing the cup with the water and subtracting the mass of the cup. Record the data on both the student and class data sheets.

Mate
Find a partner (must choose a different partner each time). Determining mouthparts of offspring:  Each student randomly draws one utensil card from their partner to determine mouth parts of the offspring.  On each student data sheet, record both cards (it takes two cards to determine the mouth).

Repeat to obtain the mouthparts for the 2nd offspring.

Spoon + Spoon = Spoon

Spoon + Fork = Spoon (if dominant) or Fork (if recessive)

Fork + Fork = Fork

Determining color of offspring:  Each student randomly draws one color card from their partner to determine the color of offspring.  Record both cards (it takes two cards to determine the color). Repeat to obtain the color for 2nd offspring.

Blue + Blue = Blue

Blue + Gold = Gold

Gold + Gold = Gold

One student will then choose to be the 1st offspring and the other student will choose to be the 2nd offspring.
Students will get the appropriate cards so they again have 4 cards that represent the desired trait:

For example, for 1st offspring, if 1st pick was gold and 2nd was blue, student who becomes the first offspring will make sure they have 2 gold cards and 2 blue cards.  

If for the 2nd offspring, 1st pick was gold and 2nd pick was gold, student who becomes that offspring will make sure they have 4 gold cards.

Now that the students have become their own offspring, record the class data for both color and mouth parts.

Complete 6 rounds of feeding then mating.  Record the class data for color and mouth part after each mating and food after each feeding. This creates baseline data for comparison. 
Each time mating should be random – simulated by students having to mate with someone they haven’t mated with before.Number of rounds of mating is not as important as having distribution of traits stabilize (so you have both colors represented).

Selective Pressure

Have students feed for 30 sec from the food source beaker.

After 30 sec, determine the mass of the food collected in stomach cup by massing the cup with the water and subtracting the mass of the cup. Record the data on both the student and class data sheets. Include student initials on the class data sheet.

Eliminate the 2 students with lowest mass (ate the least).  Assign them to the two highest eaters to become an extra offspring.

Mate

Follow the mating instructions described above.

Complete 4 rounds of feeding then mating.  Record the class data for color and mouth part after each mating and food after each feeding. Each time mating should be random – simulated by students having to mate with someone they haven’t mated with before. 
Number of rounds of mating is not as important as having distribution of traits stabilize (so you have both colors represented).

Environmental Change – Drought

Reduce the amount of food to 500 mL due to drought conditions.

Have students feed for 30 sec from the food source beaker.

After 30 sec, determine the mass of the food collected in stomach cup by massing the cup with the water and subtracting the mass of the cup. Record the data on both the student and class data sheets. Include student initials on the class data sheet.

Mate

Only those with 15mL of “food” have enough energy to mate. The top feeders will make enough babies to re-populate the environs back to the original population number.

Graph

Have students graph class data for all conditions thus far.  If time is limited instruct students to create bar graphs.

WB

White board graph trends and conclusions thus far (specifically the relationship between characteristics and survival).  Make sure students discuss the relationship between the color of the birds and their survival; the mouthpart of the bird and survival.

Post-activity discussion

Conduct a post lab discussion on results so far.  What happened when we had only forks with no selection pressure, with selection pressure, with environmental change, what effect did color have on the ability to get food or survive?  Introduce the terms, allele, variation and genetic drift.   Emphasize the random nature of trait distribution.  Ask students about changes in the number of blue or gold birds and if that was related to reproductive success.

Two traits – Different characteristics

Tell students that chicks born from eggs laid near radiation have fused mouth parts and introduce 2 spoons (or a number of spoons that will represent approximately 25% of population).  Give the students with spoons the appropriate number of spoon cards based on whether spoons are dominant or recessive.

Complete 6 rounds of feeding then mating (without any eliminations) until numbers stabilize.  

Record the class data for color and mouth part after each mating and food after each feeding. 
Each time mating should be random – simulated by students having to mate with someone they haven’t mated with before.Number of rounds of mating is not as important as having distribution of traits stabilize (so you have both colors represented).

If the spoons have increased greatly, reset the population to the original number of spoons and then re-introduce the selective pressure (competition) and complete another 6 rounds.  Follow the same protocols used when there were only forks in regards to student elimination, mating, child assignment and data recording.  Re-introduce environmental change and complete 6 rounds.  Follow the same protocols used when there were only forks in regards to student elimination, mating, child assignment and data recording.  

Graph

Have students graph the class data.  If time is limited, instruct students to use bar graphs.

WB

White board graph trends and conclusions (specifically the relationship between characteristics and survival).

Post-activity discussion

Ask students to predict future spoon population

Bring out in discussion

• Is there a need for variation in a population?

• What is the effect of competition when there is variation?

• When do you see a change in the population?

• Do any traits ever completely disappear?

Develop consensus through summary boards:

• If a trait helps an organism survive to reproduce then the trait is passed on
• If a trait does not affect an organisms ability to survive then the frequency varies
• If a trait hurts an organisms survival then it decreases
• Populations change – not organisms

Introduce the terms: adaptation, natural selection.

I think that the first time I run this I will need to just read through and follow the directions. I felt a little confused with exactly what data was supposed to be collected during the experiment. I think the kids will really get into this one as it seems silly at first. I wonder how long it will take students to realize that there are serious topics

Explain which data to collect more clearly.
Decide if traits will be dominant or recessive ahead of time.
Circulate to observe student technique and data colletion.