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NEL Cell Division 557

Exploration Observing Daphnia

Materials:prepared slide ofDaphnia, concave depression slide,

glycerin, cover slip, Daphniaculture, medicine dropper,

microscope, ice cubes, cotton swab

• If available, look at a prepared slide ofDaphnia. Take note of
  the Daphnia’s general appearance and the location of certain
  features (e.g., eyes, antennae, heart) so that you will be able
  to identify them more easily in the Daphniaculture.


• Remove the prepared slide. Obtain the other materials. Using a
  cotton swab, smear some glycerin into the depression on the
  slide. Then, using a medicine dropper, place a small drop of
  Daphniaculture onto the glycerin. Prepare a wet mount by
  adding a cover slip. Examine the slide under low-power
  magnification. Pay attention to the movement and heart rate
  of the organism.
  
  
  • Place the slide on an ice cube for 3 min, then dry the bottom
    of the slide with a paper towel and observe once again under
    low-power magnification.
    (a) Why did you smear glycerin on the slide?
    (b) Why did you put the slide on an ice cube?
    (c) Make and label a scientific drawing of a Daphnia.
    (d) Do you think that Daphniaare composed of many cells?
    Describe any features that you observe that demonstrate
    this fact.
    (e) Try viewing the Daphniaunder medium power. (Hint: You
    may have to adjust the diaphragm.) Draw what you see.
  
  
  
  

Figure 1
Daphniais also known as a water flea, but it is a crustacean, not an insect.

eye

antennae

heart

brood pouch

intestine