The Right “Beak” for Evolution 2015
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)
(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 (1st and 2nd Simulation))
Container with Large Seeds (Galapagos island with food (2nd Simulation))
Simulation Round #1: “Feeding with No Competition on a Small Seed Island”
· 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”
· “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.
· 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.