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)

INTRODUCTION HYPOTHESIS

METHODS DATA (VISUAL)

DATA (RESULTS) CONCLUSION

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.

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

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

Data: Table 1

• Table taken from full article

DATA:

• Graph taken from full article

Diffe

renc

e in

max

imum

swim

min

g sp

eed

after

tail

rem

oval

(cm

/ se

c)

Percentage of tail depth removed during surgery

60% 50% 40% 30% 20% 10% 0%

Graph 1: Comparison of maximum swim speed between tadpoles with different amounts of their tails surgically removed

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

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.