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Semi-Formal Lab Report (SFLR) Barrett’s Class

Semi-Formal Lab Report (SFLR) Barrett’s Class. Name: Josh Van Buskirk & Andy McCollum Date : Year 2000 Class : Department of Biology, University of Michigan, Ann Arbor. TOPIC / “Big Idea” Natural selection and types of adaptations FOCUS (Circle those that apply)

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Semi-Formal Lab Report (SFLR) Barrett’s Class

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  1. Semi-Formal Lab Report (SFLR)Barrett’s Class Name: Josh Van Buskirk & Andy McCollum Date: Year 2000 Class: Department of Biology, University of Michigan, Ann Arbor

  2. TOPIC / “Big Idea” Natural selection and types of adaptations FOCUS (Circle those that apply) INTRODUCTION HYPOTHESIS METHODS DATA (VISUAL) DATA (RESULTS) CONCLUSION

  3. INTRODUCTION • One way species evolve over time is through natural selection—a process where individuals better adapted to an environment survive and reproduce more, which makes their traits more common in the population. • One type of adaptation created by natural selection is the ability of an organism to change its morphology when it detects factors in its environment. • For example: many species of tadpoles change the morphology of their tail when they detect pheromones given-off by other tadpoles being eaten / attacked. • We investigated how the tadpoles’ response (growing a larger tail) could help it survive predators.

  4. HYPOTHESIS • If large tails help tadpoles survive because the large tails improve swimming, then tadpoles with large tails will be able to swim better than tadpoles with regular tails

  5. METHODS • Collected 144 tadpoles from ponds with no predators (these tadpoles had regular tails) • Collected 144 tadpoles from ponds with predators (these tadpoles had large tails) • Raised 270 tadpoles in the lab and removed different lengths and depths of their tails • Measured size and shape of body and tail for each tadpole • Measured maximum swimming speed, angle of escape, and time to reach a 2.5 cm radius for each tadpole • Used multiple statistical tests to determine relationships between tail size and swimming speed

  6. Data: Table 1 • Table taken from full article

  7. Graph 1: Comparison of maximum swim speed between tadpoles with different amounts of their tails surgically removed DATA: • Graph taken from full article Difference in maximum swimming speed after tail removal (cm / sec) 30% 10% 0% 50% 60% 40% 20% Percentage of tail depth removed during surgery

  8. DATA PATTERNS (“RESULTS”) • Tadpoles with large “predator-induced” tails swam at the same speed as tadpoles with regular tails (See Table 1) • Tadpoles with 10-30% of tail surgically removed swam just as fast as tadpoles with whole tails (See Graph 1) • Having a smaller tail did not change swimming speed, except when more than 50% of the tail was removed

  9. CONCLUSION(S) • Our hypothesis was disproven because our data showed that tail size and swimming speed were not correlated • We know that tadpoles with larger tails survive more often because other studies have shown this to be true • Having a large tail must do something else to allow the tadpole to survive better when it is in an area with predators.

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