SQUID DISSECTION

On last friday, our class did a squid dissection and it was really fun. Squid are members of the phylum Mollusca and of the class Cephalopoda. These squids that we can easily find and eat have the most complex brain of any invertebrate. Cephalopoda means "head foot" and is the most morphologically and behaviorally complex class in phylum Mollusca. It was very interesting to know that squids are so smart and that they can be as small as a thumbnail or as large as a house. The purpose of this lab was to locate and identify major external and internal features and organs of a squid which I think was very successful, and also to understand and use basic dissection techniques and terms which I think was very successful as well. Unlike the earthworm, it was not difficult to find and recognize the organs.
After finishing the dissection and questions, I came to have better knowledge of mollusks which we have been learning in the class.

image from google.
Here in the picture, it says there are 8 arms and 2 tentacles, but you can also say that squids have 2 arms and 8 tentacles.

image from google.
If we say the longer ones are arms and shorter ones are tentacles, the arms have many purposes including reaching out to capture food, and also play a role in mating. And the tentacles are used to aid in feeding and grasping objects in range of the beak.

image from google.
Squid use jet propulsion to move, they suck water into their mantel cavity and then expel it out very fast this shoots them along the water. they move to the opposite direction of the direction of water coming out.

image from google.
The external features that are adaptations for the squid's predatory life are the rings of teeth on the arms  and the eyes. The teeth make the squid very easy to capture preys and the eyes are very light-sensitive that they can see preys through darkness in the deep ocean.

image from google.
The general traits of mollusks are that they are bilaterally symmetrical and that  they have soft body and mantle

image from google.
The squid have 1 pair of gills, one on each side. 

image from google.
The ink sac empty into the ocean to disguise the animal's presence. and the function of it is to spray out the ink to enemies for escaping.

image from google.
The pen supports the squid's mantle and serves as a site for muscle attachment. If it had no pen , the squid won't be able to hold its body up.

image from google.
The squid has a complete digestive system, with stomach, intestine and anus. The wastes exist through the anus.