INGESTION AND DIGESTION
IN Hydra

Animals differ from plants in being hetertrophic.  That is, they are unable to make the basic chemical nutrients they require, and thus must prey on other animals or plants for the basic chemicals necessary for their metabolism.  Hydra is no exception.

*   The purpose of this exercise is to observe Hydra eating small animals (Daphnia) and to learn how digestion takes place to obtain the essential food requirements.


MATERIALS

Hydra culture
Daphnia

Compound microscope
Slide and cover glass
Medicine-dropper pipettes


PROCEDURE
1. With a medicine dropper, obtain several Daphnia from the culture jar.
2. Place the Daphnia in the center of the depression slide with the hydra.  Cover the animals with the coverslip.
3. Observe them for several minutes with a dissecting microscope or a hand lens.  Return the hydra to the culture jar labled "Just Fed Hydra".

Biology




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