Students in
Comparative Anatomy have been studying worms the past couple of
weeks. We started off working with Planaria which are
flatworms in the Phylum Platyhelminthes. An interesting
adaptation that Planaria have is that they can grow back lost body
parts. If you cut a Planaria in half, two Planaria will
develop. This is an example of asexual
reproduction.
Earthworms in the cold water bath.
From flatworms, we moved on to
annelids such as the earth worm. In this lab, we studied the
effect of light, moisture and a base on the behavior of earth
worms. In the first picture, Amber has half of her
dissection tray covered in black paper. She then shines a
light above the tray and sees which way the worm
travels.
We then put the
earthworm into a cold and a warm situation and measured their heart
rate by watching the dorsal blood vessel contract. The middle
picture shows all of the worms in the cold water bath. The
worms slowed down their activity. The girls then put the
worms into a warm water bath and the worms became very excited
which was evident by their movement and their increased heart
rate.
