- Why did this activity require two test tubes, if only
one was needed for the Elodea sprig?
(Test tube "B" served as the control, while "A" was the
- What happened to tube "A", into which the Elodea
sprig was introduced?
(Other organisms began growing in and on the inner surface
of the tube.)
- What happened to tube "B"?
(Most likely, this tube retained the same sterile appearance
- unless it was accidentally infected with organisms.)
- What types of organisms were transferred along with the
(Answers will vary but may include snails, other types of
algae, rotifers, copepods, and various protozoa species.)
Suppose you wanted to introduce Elodea, and only Elodea,
into a new environment. How could you improve the transfer
technique so that few if any unwanted organisms were imported
into the new environment?
(Accept all reasonable answers such as swiping plant surface
with alcohol, isolating sprigs before transferring them, etc.)