The Right “Beak” for Evolution 2015

 

Introduction

    

     How does a genetic mutation in beak shape help to allow a bird to survive in its environment and thus allow the bird to pass on the beak shape to its offspring? Finches on the Galapagos are excellent examples of how a species' gene pool mutated but became adaptable to the environment.  The finch diagram below illustrates the way the finch has adapted to take advantage of feeding in different ecological niches over millions of years.

 

 

     The bird beaks have evolved over time to be best suited to their function. For example, the finches that eat grubs have a thin extended beak to poke into holes in the ground and extract the grubs. Finches that eat seeds and nuts would be less successful at doing this because their beaks are more claw-like giving them a better advantage where seeds and nuts would be found.  Keep in mind that availability and competition of food and space are important factors in defining different species, such as with the finches, on the Galapagos. The hypothesis is that if various beaks are used to simulate adaptability, then birds with effective beaks will be more successful in their environment. 

 

 

 

Materials: Per Group of 4-5

 

Test Tube Holder (beak) Clothespin (beak) Forceps (beak) Chopsticks (beak) Scissors (beak)

(4-5) Petri dishes (bird’s crop, “a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion”)

 

Container with Small Seeds (Galapagos island with food (1^st and 2^nd Simulation))

Container with Large Seeds (Galapagos island with food (2^nd Simulation))

 

Timer (clock)

Calculator

 

Procedure:

 

1. When directed you will be placed in groups of 5 and then renamed with a letter (A-F).
2. Once in your groups, assign a (mole, gopher, and vole)
3. Once in your groups, assign each other a number between (1-5).
4. When told, your number will correspond with a simulated “beak” (to be announced).
5. Gather all necessary materials for the activity when directed.

 

Other:

 

• The simulation will include 2 rounds: “No Competition” and “Competition”
• Students assigned #1 are to go first followed by #’s 2 through 5.
• Petri dishes and seed islands are to remain on the table.
• Any seeds that fall on the table or floor do NOT COUNT.
• Depending on the beak assigned, “NO SCOOPING or STABBING” of seeds.
• Best to be methodical rather than being sloppy and inefficient during the activity.
• If you gather a lot of seeds, simply spread them out evenly on your Petri dish, divide the dish into 4 quadrants, count the number of seeds in one quadrant, then multiply that answer by 4 to get a “fairly” accurate seed count.

 

 

 

      Simulation Round #1: “Feeding with No Competition on a Small Seed Island”

 

1. Place the container “island” with the “Small” seeds on the table in the middle of the group.   
2. When told, take turns picking up as many seeds as possible in 30 seconds beginning with bird #1. 
3. At the end of “your” turn:

·         Count the number of seeds you collected and record the results on your data table.

·         Tell everyone how many seeds you counted and have them record your results in their data table.  

·         Return your seeds back to their original “island” container.

·         If you chose or were elected to be the, “vole” and after you have recorded your data onto your data table along with everyone else’s results, record everyone’s results on to the computer spreadsheet as directed.

·         As a group, now answer the questions on your Result/Data sheet (1-5) + Picture.  

 

 

 

 

 

Simulation Round #2: “Feeding with Competition on Successful Islands”

 

1. Based on the number of seeds you collected, you will then be placed on one of the following islands:

·         “Successful Group Island(s) with Small Seeds (may be more than one island/group)

·         “Unsuccessful Group on Island(s) with Large Seeds (may be more than one island/group)

      Note: The “Unsuccessful Group” from the first simulation had to move to a Large Seed island because they could not have survived on the Small Seed Island with their beaks.

·         You will then be placed in sub-groups based on your beak.

2. Place the appropriate container “island” with the seeds on the table in the middle of a sub-group.
3. When told, everyone at the same time is to pick up as many seeds as possible in 30 seconds.  

4. At the end of the simulation:

·         Count the number of seeds you collected and add them with the rest of the group’s seeds.

·         Have one member of your group record the group’s data on to the computer spreadsheet as directed.

·         Return your seeds back to their original “island” container and return all materials

·         Once all groups have their data recorded on the spreadsheet add those numbers to your table too.

·         As a group, now answer the questions on your Result/Data sheet (6-10) + Conclusion.