Monday, December 10, 2012

Squid dissection



      Last Friday had topped the worm dissection by far! With squids being one of my favorite animals, it was a really cool experience to take a close look at their anatomy. Prior to the actual dissection, we were told to complete the pre-lab which consisted of labeling the interior and exterior of the squid. Shortly after this task was completed, my lab partner and I were able to head up to the front and retrieve our squid. When my teacher opened up the container of squids, they gave off an unpleasant smell; however, the smell miraculously went away once we started dissecting them. I must of gotten used to it at that point. The objective of this dissection was to take a close look at the body shape of the squid. Before my partner and I actually cut it open, we spread it out on our dish and carefully examined its tentacles and head. We also managed to take a look at its beak. It was really cool how we were able to physically move around the squid and take a look at its body parts instead of reading about it in the textbook. It's one thing to read it, but being able to play with it and cutting the squid open was a whole new experience!

     As for the actual dissection, I enjoyed this one a lot more than the earthworm one, but even then, I still found the earthworm dissection fascinating! Since using a scalpel was not an option, I cut open the squid's head with a pair of scissors and we carefully examined it's organs. It was really cool to see it's anatomy because it looked so different than the earthworm's. We managed to remove the beak ( although in three pieces ) and we got to take a close look at it. Sadly since it was small, we couldn't see too much, but it was interesting because that one of the only few hard parts of the whole squid! The most unusual part to me was the inner skeleton part. ( It kind of looked like a piece of plastic. ) Without our teacher's help, my lab partner and I would have been left confused on the whole ordeal because we were clueless. Shortly after finishing the procedure  my lab partner and I attempted to take out the squid's eyes. Our first attempt failed because we punctured the eye with a scalpel and it's residue spewed out, but we managed to make a clean cut on the second eye. Excited, my lab partner and I took a look under the microscope and it was really interesting. That was probably my favorite part of this whole dissection. These labs really help me learn about the anatomy of the organisms because it's a hands on experience! I hope we can do more of these labs because they're a really fun way to learn!

1.) My squid had eight arms and two tentacles.


2.) Based upon the structure of the tentacles and arms of a squid it is presumed that they are used for different purposes. The tentacles are used for grabbing onto prey or latching onto surfaces because their suction cups are located on the tentacles. Their arms are more used for locomotion because since it is shorter, it can move quicker.

Here is a closer look at the squid's arms and tentacles.

3.) The arrows pointing away from the body is the direction in which water comes out of the funnel and the arrow pointing towards the head reigon of the squid indicated which direction the squid will move.

4.) Two external features that are adaptations for a squid's predatory life are :
A.) Suckers on the tentacles : They are used to grab a hold of prey and make sure that they cannot escape.
B.) Beak : The beak is used for picking apart the squid's prey which makes it easier for digestion.
 Here is a picture of the beak that is located on the underside of the squid.

5.) The two traits that a squid shares with other mollusks is :
A.) Bilateral Symmetry : The squid demonstrates bilateral symmetry.
B.) Visceral Mass : The soft bodied portion of the squid that contains the internal organs.


1.) The squid has 2 gills.

 Only one gill is visible in this picture, but regardless there are two gills in a squid.

2.) The ink sac empties into the water jet and it is used to defend against predators.
 I could not get a photo of the ink sac on my own, so I borrowed a photo from Mr. Shaineel Sharma.

3.) The function of the pen is to stabilize the squid for swimming.
 When we first found this, we were unsure to what it was, but with a little clarification from the teacher, we learned that it was the pen.

4.) The squid excretes waste through the anus then the water jet.
I did not have an overview of the anus and water jet, so here's a picture of a squid.




We managed to cut out the eye and get it under the microscope.


 Since Mikey and I got bored, we decided carve Slayer into the squid's collar.

Tuesday, December 4, 2012

Worm dissection



        A couple days ago, our biology class got to experience our first ever dissection! During this lab, we got to cut up dead worms in order to learn about their anatomy. This was the first time ever that I have ever paid so much attention to a single worm. Normally when I see one crawling along, I disregard it and keep on walking, but because of this lab, I got to personally see what it looked like on the inside! Seeing the worm all cut up on our tray really gave me a new perspective on just how these little guys work. Prior to making the first incision, I got to carefully examine the exterior of the worm. In doing so, I got to take a look at all the different parts of the worm such as the clitellum, setae and the mouth. After pinning the worm down on the tray, I was able to successfully able to slice the skin in two and I was able to pin it all down with very little damage to the organs, but we managed to see a heart and the brain most clearly. Upon cutting the worm, a black liquid oozed out of the worm which was pretty interesting and had a not so pleasant odor. Our group managed to perform a perfect incision on the head and the brain was left untouched. Shortly after examining the upper half of the worm, we began to take a look at the bottom half, the excretory system. There was not too much here, besides the reproductive organs ( such as the testes and ovaries ). Along with the reproductive structures, the rest of the bottom half had just soil and blood. After the lab was over, I took home valuable information about the anatomy of the earth worm. With all of this new information that I learned, I will be able to look back upon this experience and apply this newly gained knowledge to future assignments and quizzes. Apart from visiting the aquarium, this was probably the coolest things we've done!

1. The name of the pumping organs of an earthworm are the five aortic arches, which is more commonly referred to as hearts.

A heart is located in the dark mass of blood and organs.

2. The worm's digestive tract goes as follows :
Mouth: The opening to the digestive tract
Pharynx : Helps suck the food in
Esophagus : Moves food to the crop
Crop : Moistens food
Gizzard : Grinds up the food ( Mechanical digestion )
Large Inestine : Further digestion and absorption ( Chemical digestion )
Anus : Excretes waste

Here is a picture of a worm fully cut open. You can see the different organs of the worm and the path that it takes.

3. The part of the earthworm that serves as its brain is the cerebral ganglion. It is connected to the rest of the body through a ventral nerve cord.At each segment of the ventral cord is a ganglion which is a swollen region of nerves that connects every segment to the brain.

Here is a close up image of the worm's brain.

4. The parts that are included in the worm's excretory system are the anus and nephridia.
 A picture of the lower half of the worm. ( Where the excretory system is located )

5. You can find out what a worm eats if you take a look at its digestive system. If you dissect the worm, you can actually find soil that was traveling through its body.
 Dissecting the worm can show you its diet.

6. The setae found on an earthworm are tiny bristle like structures that assist in movement. They help by latching onto terrain so predators cannot pull them away..
I was unable to take a picture of the setae so instead, I found a picture that the setae is clearly visble.

7. The earthworm's crops store the worm's food as it comes down the esophagus and the gizzard grinds it down. This process makes the worm well suited to its environment.
Here is a picture that shows the esophagus and gizzard.

8. If I cut past segment 32, I would see the rest of the digestive system, nephridia and the worm's food.
This picture shows a portion of the bottom half of the worm. It shows the digestive system and some nephridia.

9. When earthworms start to reproduce, they both exchange sperm with one another because they are hermaphroditic. Both worms would then proceed to collect the sperm in special sacs where it will stay there until it is mature. Once this happens, the worm's clitellium begins to create a sticky substance that will form a ring which contains the now fertilized eggs.
This picture shows the worm's seminal vesicles.