Invertebrate Project

Grimpoteuthis

Dumbo Octopus

 

Phylum: Mollusca

Class: Cephalopoda

• Protosome 
• Bilateral symmetry
• 3 germ layers

Essential Functions

Body Structure:

• Ear-like fins on top of the head
• 8 tentacles connected by webbing
• Tentacles have 1 row of suckers and 2 rows of cirri (fleshy spikes) 
• Dumbo octopus can grow to 20-30cm long

Digestion (Feeding):

• Grimpoteuthis eat crustaceans, worms, bivalves and small fish
• They hover over the bottom and use their tentacles and cirri to get food into their mouth
• Their radula is reduced or totally gone
• Therefore, they swallow prey whole!

 

Circulatory:

• All octopi have 1 main heart and 2 smaller ones near their gills
• The smaller ones pump blood to the gills and pump blood with oxygen to the main heart
• Octopus blood has hemocyanin which makes it blue instead of hemoglobin that would turn it red

Respiration:

• The Dumbo octopous respire the same way as other octopi, they use gills to get oxygen from the water
• As the oxygen passes over the feathery gills it gets passed into the blood and transported trhough the body

 

Excretion:

• The Dumbo Octopus has an anus to release solid waste
• They also have nephridia that collect fluids, concentrate them and put them with the other waste going out the anus
  

Movement:

• They hover over the sea floor
• To move they expand and contract their webbed arms
• They are also able to shoot water through their funnel 
• They can also flap their fins on their head

Reproduction:

• Females lay eggs all year round, have no specific breeding season
• They lay their eggs under rocks and leave them to fend for themselves
• Males have a large segment on their arm to transfer sperm packet (spermatophore) into female mantle cavity
• Packet ruptures when it enters and fertilizes the eggs

Another organism in the phylum Mollusca is the squid.  Squids are similar to octopus because they are both in the class Cephalopoda.  They both have arms with suckers on them however, squids also have two long tentacles that they use to capture their prey.  They also have a closed circulatory system filled with hemocyanin similar to octopi.  Both cephalopods squirt out ink when they feel endangered.  Squids and octopus can both move by jet propulsion but the dumbo octopus has fins on its head that it uses to swim as well. 

Interesting Facts:

• Dumbo Octopus can be found from 400m - 4800m deep in the ocean
• The largest one ever found was about 6 feet long and weighed 13 lbs.
• There are 37 known species of the Dumbo Octopus

I love this Invertebrate because of it's interesting appearence and it's unusual resemblence to the Disney character Dumbo.



 

Squid Dissection

On Friday December 7 we go to dissect squids in class.  This experiment allowed us to locate major organs inside and outside of the squid and examine the squids features.  In class we had been learning about different mollusks and their body parts and different behaviours.  We had learned about the three main classes of mollusks which include Gastropods, Bivalves and Cephalopods.  The Gastropod class included snails and slugs, the Bivalve class includes clams and oysters and the Cephalopods include octopi and the squid we dissected.  We learned that all mollusks are composed of three parts; the visceral mass, the foot and the mantle.  When we opened up the squids we were able to see all of these parts.  On the outside of the squid we saw the arms that the squids use to take in food and that surround a strong beak that they use to tear their prey.  In class we learned about how squids shoot out a cloud of ink when they feel threatened and when we dissected the squid we found the ink sac and used the ink to write with, almost like a pen.  Dissecting the squid was helpful for me in some ways since it did provide a visual aid for my learning but since not all the squids were completely mature some of the body parts were missing so we couldn't see them.

External Anatomy Questions

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

2.) The arms have sucking disks on them so they are used to grab their prey.  The long tentacles also have suckers but only on the ends.  They are used to help eat prey.

3.)








4.) Two external features on the squid that are adaptions for the squids predatory life are that it can move quickly through jet propulsion and that it can squirt out dark ink.  Moving quickly is helpful for the squid because it can swim away from predators and escape if they can't swim as fast as it.  Being able to squirt out ink is a helpful adaptation because it can temporarily hide the squid or confuse the predator.






5.) Two general traits that squids share with other mollusks are that they all have trochophore larvae and their body forms are all similar; they all have a foot, shell, mantle cavity and visceral mass.





Internal Anatomy Questions

1.) The squid had one pair of gills.       

2.) The ink sac empties into the funnel and is squirted out when the squid is scared to try and get away from predators.









3.) The pen supports the structure and without it the squid wouldn't be able to hold its shape and it would collapse in on itself.









4.) Waste goes into the anus and then gets emptied into the water jet which releases the waste outside the body.

Annelid (earthworm) Dissection

Last Friday on November 30th our Biology class got to dissect earthworms. Between each pair we got one worm and we had to pin it down and carefully slice it open so we could investigate the parts inside. Having us observe the inside of real earthworms was an interactive and exciting way for us to learn more about how the digestive, nervous, circulatory and reproductive systems work and what they really look like. After doing this dissection I found that I had a better understanding of segmented worms and it was a good learning tool in addition to the information we had learned in class. In class we had learned about the different parts of the digestive system such as the mouth, the esophagus, the pharynx, the crop, the gizzard, the intestine and the anus. When we opened up the worm we were able to see all of these parts and the track that the food and soil it ate would travel. We had also learned about it's circulatory system in class. We found out that they have five "hearts" or pairs of aortic arches and these we found inside the body as well. In our notes we learned the biological role of earthworms and how they are composters that help turn organic matter into fertile soil. When we opened the worm my partner and I opened up the intestine and we could see the soil that was travelling towards the anus and being turned into a fertilizer. At first I found cutting open an earthworm a little bit gross but seeing all the knowledge we had learned happening inside this body really helped me understand the information more.

1. The pumping organs of an earthworm are pairs of aortic arches, or hearts.

2. The earthworms food enters through the mouth, goes into the pharynx, enters the area between the pharynx and the crop which is called the esophagus, then it enters the crop where the food is stored for a little while, next it is broken up in the gizzard, then it goes through the intestine where it's body absorbs the nutrients and lastly the waste passes through the anus.

3. There is one pair of ganglia above the pharynx which act as the brain of the earthworm and are connected to the rest of the body by the ventral nerve chord.






4. The two parts of the earthworms excretory system that we saw were the nephridia and the anus.




5. To find out if an earthworm eats soil you can open up the intestine and see what is inside of it.





6. The setae help with the earthworm's movement through their dirt environment. Without the setae they wouldn't be able to move very well.



7. The earthworm's digestive system is able to absorb all the nutrients from the food it eats and turn the soil and other waste into a fertilizer.


8. If we were to dissect the earthworm to the posterior end we would have seen the remainder of the intestine, the anus, the rest of the ventral nerve chord and some of the nerves coming off of it.





9. Earthworms are hermaphroditic, they contain both eggs and sperm. When they are ready to be released from the body the eggs exit through the female genital pores and e sperm go through the male genital pores. Each worm has a clitellum which protects the eggs in a cocoon structure. When an earthworm wants to reproduce they attach to another worm and exchange sperm, which travels into the seminal receptacles of its mate

Overall, we were able to find organs from the reproductive, digestive, nervous and circulatory system. Seeing all these systems for real put all the facts we had learned about earthworms into an accurate.