Rat Dissection

For our biology classes final dissection of the year, we were to dissect a rat. This dissection was much bigger than what we've previously done, beating the earthworm and the squid by a long shot. We were given the usual tools for the dissection, a scalpel, pins, and tweezers, yet our group was still divided on who should be the one to cut the rat open. By that i meant that no one wanted to do it, leaving it to me to start the dissection.We analyzed the external anatomy first, finding the rat's various body parts and openings, including the urethra, anus, and mouth. It was now time to cut our rat open. we made our first incision along the length of the rats stomach, and splitting the lines along it's hind legs and fore legs. Upon opening it's body, we found the rat's digestive cavity, and it's rib cage  which we cracked open at a later time to get at the heart and lungs. We were able to identify the small and large intestines on sight, and the stomach and other processing organs, like the liver and kidneys after some digging around. The thing that surprised me about the worm was how similar it was compared to our anatomy. It would have to do with the phylum that we are grouped in, as well as our class of mammalia. The dissection was a truly interesting experience, even more so since they belong in the same phylum, sharing similar organs and body functions that we do, even with some differences due to the differences of our orders. The rat dissection was a fun experience and i hope to see what things that'll be done next year in biology!

1. Why are your hands the best tools for dissection?
Our hands are the best tools for dissection as they are very versatile, much more so than most other tools, and we can control them much better considering they are our own appendages. They also help us feel what we are dissecting, allowing us to understand the purpose of the dissection more so than with a cold tool.

2. What is the purpose of having all the different titles and labels for the dissection?
They provide accurate information towards the assignment at hand, and allow us to focus in specific parts of the body, instead of aimlessly wandering around the inside of the body.

 3. In what way does the tail differ from the body?
The rat's tail is much more stiffer and coarse, as well as appearing to have scales along the length of the tail.

4. What purpose is served by the vibrissae?
The vibrissae allow the rat to detect disturbances or changes in its environment.

5. Your specimen is bilaterally symmetrical, what does that mean?
This means that the rat has a line of symmetry, meaning that one side of the rat would be the same as the other side of the rat, laterally speaking. This also means that this species is highly developed, as all developed phyla exhibit bilateral symmetry.

6. The sphincter is described as a circular muscle. Why is it this shape and what does it do?
The sphincter is an opening that regulates the flow of substances, such as urine or blood. They are circular to fit into the shape of the tubes that they belong in, which are also circular in shape.

7. Why is there a difference in size between the small and large intestine?
The intestines differ in size as the large intestine is made to process and create the waste, while the smaller intestine is smaller to increase nutrient absorption as it passes from the stomach.

8. The liver is the largest organ in the body, what purpose does it serve?
The liver is a processing organ, like the kidneys. They detoxify the things taken into the body and create chemicals to aid in digestion.

9. How did the duodenum acquire it's name?
The duodenum is names after 12 finger widths (around 20 centimeters) and has a Latin origin.

10. What purpose does the appendix  provide in animals that still retain it as a functioning organ?
The appendix is used to breakdown cellulose, mainly found in the diets of herbivorous mammals. The organ contains bacteria which assist in the breakdown of cellulose.

11. In each cavity, there is a membrane that covers both the wall of the cavity and the organ it 
contains. What is the function of the membrane?
The function of this membrane, like all the other membranes of the body, is to protect and contain the organs and parts of the body to prevent damage, like for example the organs mixing up with another, changing places with where they are supposed to be.

12. What is the function of the spleen?
The spleen works as part of the immune system and produces/stores blood cells for the circulatory system.

13. What is the function of the diaphragm?
The diaphragm controls the flow of air into the lungs, pulling the lungs upwards and downwards to expand
the chest cavity to let air in.

14. What distinguishes the atria from the ventricles?
The atria hold the blood as it enters the heart, keeping it until it is then passed onto the ventricles, which push he blood to where it needs to be.

15. Why is the wall of the left ventricle thicker than the right?
The left ventricle is responsible for pumping oxygenated blood to the entire body. This means that the thicker wall is meant to give it more power to push the blood as far as it needs to go, unlike the right ventricle, which only needs to take blood to the lungs.

16. What similarities exist between the male and female reproduction system?
The male and female reproductive systems are both completely different, aside from the adrenal glands and the connection to the bladder. They also share the pituitary gland.

17. What do the kidneys do?
The kidneys are responsible for processing the blood, getting rid of as much waste as possible. It collects the waste from the blood and sends it to be excreted in the form of urine.

18. What system of the body do the thymus, thyroid, and adrenal gland belong to?
The thyroid, thymus, and adrenal glands all belong to the Endocrine system, or the system responsible for the control and releasing of hormones involving the metabolic function of the body.

THYMUS- Produces T-cells for the immune system

THYROID- The largest endocrine organ, and controls how sensitive the body is to other hormones, makes protein, and controls how quickly the body uses energy

ADRENAL GLAND-Releases hormones in response to stress and affect kidney function.

Squid Dissection

A very interesting way to finish our school week, our biology classes squid dissection was very exciting, and definitely a lot cleaner than the messy insides of the earthworm we cut into last week. It was also much more hard hitting, as this was something that a lot of people eat (unlike earthworms), and actually finding out what was inside what we eat was a unique experience on its own. Once again we got ourselves ready, arming ourselves with the scalpels, pins, forceps, etc. and dove right into the dissection. Sadly, before we could get into the squid, we had to examine its external anatomy, counting its arms and tentacles, which confused our entire class as tried to find out which ones were the tentacles and which ones were the arms. After the examination, we were ready to find out what the squid, quite literally, was made of. Opening it's collar straight down the middle we found a cornucopia of organs and body parts. The most surprising was the jelly- like mantle, which felt like incredibly fragile jello that could easily break. We were also able to find the ink sac, a silvery, long body part that housed the squid's most flamboyant defense system. Although we didn't open it up, we saw many other groups which were able to get the ink, and even use it to write their names! Definitely the best part was opening the head and finding the beak of the squid. This body part of the cephalopod was incredible, I myself was truly surprised to find a mouth part that closely resembled a bird, even though the two classes of animal were very different. Now with a much better knowledge of the inside of a squid, we were able to fill out our pre-labs which had detailed diagrams that we had to fill out. This dissection was a great experience that showed us how intricate and special all animals are, even the ones that we take for granted, like sea food in this case, and giving us a hands on look at the actual organisms that we were learning about in class. This lab was definitely one of my favorites in the year.

EXTERNAL ANATOMY                                                                                                                              


1. The squid that we were dissecting had eight arms and two long tentacles.












2. The differences between the squid's arms and tentacles are their length and their function. The squid's tentacles are long and only have suckers at the end, whereas the squid's arms are much shorter in comparison yet have suckers all along the inside on them. This would mean that the arms are meant to grasp and keep a hold of prey as well as contribute to locomotion and traction when climbing, and that the much longer tentacles are meant to feel and touch things in the surrounding environment.

3. The flow of water throughout the squid is controlled by the funnel and water jet. The water come in through the funnel, and is then expelled like a jet, in the direction of the tentacles. This causes the squid to propel itself in the opposite direction.





4. Suckers- found on both their tentacles and arms, these numerous, tiny suction cups are made to stick onto surfaces, as well as other creatures. They grasp the prey and the suckers make it impossible to escape.
    Beak- the squids have very powerful beak, that resembles a bird, and is made to tear apart it's prey.   Some species can even secrete a poison from here, paralyzing them.

Tentacles: RED Arms: BLUE

5. The squids have a developed foot, called the tentacles. This is what it has specialized into, like snails and their flat feet they are suited to their environment. The squids also a share a soft body that all mollusks are known by. Although most cephalopods have evolved to not need hard shells for protection, they still resemble all other mollusks in this way. Another similarity between cephalopods and other mollusks are the bilateral symmetry that they exhibit.




INTERNAL ANATOMY                                                                                                                            

1. The Squid has a single pair of gills, each located on one side of the body. This feathery structure is the main source of gas exchange in the squid, exchanging oxygen in the water that it needs to survive.













2. The Squid's ink sac is it's most unique defense and escape mechanism. It empties ink into the squids funnel when it's threatened by a predator. This sudden jet of ink in the water acts as a smoke screen and disorientates the attacker and allows the squid enough time to escape. Some species even shoot out a poison with the ink, paralyzing the intruder for a time.

3. The pin provides structural support for the squid. It is located along the inside of the mantle, and is attached to the muscles. It supports the mantle and is technically a vestigial structure as it used to be a shell until evolution saw fit to remove it. If it was gone, the squid might suffer from a less structured body, but since it is a vestigial organ, it probably won't suffer much from its removal.

4. The squid's excretory system consists of the anus, which is the main way through which waste is released. Another way the squid is able to rid itself of waste is through the water jet, where it can release water, as well as any waste that it may have.







Probably the most interesting part of the lab was finding and opening out the beak to make it more visible. It was fascinating to see how it resembled the beaks of birds even though the two classes of species are very different from one another.

Our Worm Lab

1. The pumping organs of the Worm are its hearts, or enlarged blood vessels

2. It first enters through the mouth, then the pharynx. It travels through the esophagus and into the crop and gizzard, and then through the intestine until the waste is excreted through the anus

3. The worms brain is made up of several ganglia, which is attaches to a long nerve that runs along the ventral side of its body, which connects it to the rest of the body. 

4. The parts of the worms body that are involved with the excretion of waste are the anus, and the nephridia, (which we could not find our lab sadly)

5. You can find out the worm's diet by looking at what can be found in it's digestive system. Soil for example will be found travelling through the digestive system, and if dissected, you can actually see what the worm ingests

6. The earthworm's setae are tiny bristle-like structures found on it's skin. These are very helpful in the movement of the worm, and they protect it by spiking out in soil to prevent any predators from grabbing it away from its habitat ( since my camera couldn't take a nice picture of the setae, i was able to find a species of worm with very visible setae)

7. The earthworm's crop stores the worm's food as it comes in through the esophagus, and the gizzard grinds it down until it is ready to be digested. This process of storing and grinding food makes the worm very well adapted to its environment ans explains why it can extract its food from the soil.

8. Past the 32nd segment of the worm,I would see the continuation of the digestive system, as well as more nephridia. I would also see the worm's food, mostly made up of detritus and soil.

9. Once earthworms begin to reproduce, they begin to attach themselves to one another and exchange their sperm, Since all earthworms are hermaphrodites, they collect the sperm and contain it in special sacs to be used once the eggs are mature. Once this happens, the clitellum begins to secrete a sticky substance in the form of a ring which is released with the eggs and sperm. This in turn creates a cocoon, which contains the now fertilized eggs.(The picture shows the seminal vesicles, which create the sperm needed for reproduction)

For our classes first major dissection, we were assigned to dissect an earthworm from the phylum Annelid. It was definitely one of the more exciting things we've done in our biology class, and one of the best dissections I've had yet, as odd as that sounds. Being a fairly visual learner, I found the dissection to be really informative, and quite the experience. We began with the pinning of the worm to the dissecting table, which brought more than a couple of squeals from my classmates, but it was easily done. The real work came when we had to make the major incisions. We cut down the length of the worm's dorsal skin, exposing all the organs and body parts that the earthworm had. Pinning the skin to the side, we started to view the various organs under the microscope, like the intestine and the worm's multiple hearts. Definitely the most disgusting part was when we viewed the bottom  half of the worm, which for us, contained the intestine, typhosole, and  the earthworm's diet of soil and decaying matter. The brown-black mess was eventually moved away as we wanted to view the worm's intestines in it's entirety. Once we were done, we spent a good amount of time cleaning up the various scalpels, pins, tweezers etc. and getting pieces of worm off of every surface that was visible. In the end, the dissection was a truly interesting experience, and i definitely helped us actually see what was inside of what we were learning about, not just be looking up diagrams of it in out textbooks and on the internet. This hands on experience makes what we're learning about that much more interesting and special.

Flatworms from around the ocean

Genus	Eurylepta
Species	sp.
Family	Euryleptidae
Order	Polycladida
Location	Shimoda, Izu Peninsula, Sagami Bay, Japan
Length	about 6 mm
Depth	intertidal
Date	August 24, 2002

Genus	Pseudoceros
Species	sp. 2
Authority	Newman & Cannon, 1998
Family	Pseudocerotidae
Order	Polycladida
Location	Solitary Island, Coffs Harbour Region, New South Wales, Australia

Genus	Pseudoceros
Species	dimidiatus
Authority	von Graff, 1893
Family	Pseudocerotidae
Order	Polycladida
Location	Kailua-Kona, Hawaii

AQUARIUM TIME!!!!

 1. Since the Clown fish are are immune to the sea anemone's stinging nematocytes, due to their similar skins, they can live safely within them, keeping the anemone clean as they are protected by the anemones poisonous tendrils found on their tendrils.

 2. Sea otters have some of the thickest coats of any animal, and this is important to their survival on a cold ocean, since they lack blubber, they need to maintain their coats to make they stay warm, and to keep the insulating layer of air maintained in between the fur and skin.

 3. Before the 1900's, one could find the sea otters living all along the western coast of North America, from Alaska to California. After decades of hunting and poaching, their numbers dwindled, and in an attempt to reintroduce the population, they brought in 89 sea otters from Alaska  and brought them to the west coast of Vancouver island in the year 1969.

4. The colour of this species of anemone were bright green, a severe contrast to the brown and grey rocks that they lived on.

 5. My favorite invertebrate was the jellyfish, in this picture, its the Moon Jelly. As for it's adaptations, they have a simple nervous system to balance them and some even have the ability to detect light. In addition to this, they have poisonous and painful tentacles that they use to deter predators and to capture prey. These tentacles shoot out spiked nematocytes that inject poison and puncture the skin.

 6. the scientific name for the Beluga Whale is "Delphinapterus" which means Whale without fins. It is also referred to as the "white Whale" and the "sea canary" due to their constant chattering.

 7. The seahorse is a very slow moving sea creature, which constantly hugs close to kelp and other plants to stay camouflaged, and when they have to move, they do so slowly.

8. The head of the jelly fish can represent the head, which is where the main part of the nervous system is, and the tentacles can respresent the conntless nerves that go throughout our body. 

 9. The starry flounder has two important adaptations to survive. It's first one is the ability to camouflage with the ground it makes its home on, and it's other adaptation is its ability to play dead for long period of time to escape predators.

10. When feeding on plankton, the Moon Jelliescontract and expand their epidermis on theri "head" and in doing so they bring water into their Gastro Vascular Cavity. This water contains planktons, which the jelly with feed on.

 11. The suction cups of the Pacific Octopus help the octopus climb up surfaces and to attach to prey so they cannot escape. In addition to this, they also have some of the best camouflage in the underwater world, able to change pigments to resemble rocks, kelp, and even coral. This remarkable adaptation makes them very capable predators, and one of the best in nature.

 12. The varying feeding types of stellar sea lions changes constantly. They are mainly pack feeders, working together in groups to get prey. They eat a variety of seafood, from squid and octopi to herring and pollock.

13. The caiman originated from the areas around Bolivia, Argentina, Brazil, and Paraguay

14. The crocodiles muddy and dark colours help it greatly to blend in with its environment. Since they live in rivers and tropical sea, their colours help to camouflage them so they can capture prey easily

 15. The name opf teh largest fish in the Aquarium was the Arapaima, a 3 meter long freshwater fish that lives in the Amazon

 16. The Redhook Silver Dollar, and it eats seeds that fall off riverside shrubs

 17. When fishers catch pirahnas, the most dangerous threat they can be towards humans is when the fishers are removing them from their hooks, as they are still alive and can still bite.

 18. Sharks do not, infact, have a bone in their body, as they entire skeleton is made up of cartilage, a much lighter and more malleable substance.

 19. Among the other fishes that were found in the shark tank, there were stingrays, various species of fish, and one large sea turtle

 20. The one main adaptation that the sea urchin has is their spiky bodies. This deterrs them from most predators, and keeps them safe from anyone who would try to eat them.

 21. The archer fish uses the water it swims in to get its prey, making for an interesting adaptation. They shoot water out of their mouths and aim at insects with lightning precision. Once the water hits the insect, it'll fall into the water and be eaten by the archerfish.

22. The turtle, which was found in the tropic zone, goes by the name Schoona

Quite possibly one of my favorite field trips of this year (sorry nature walk), our class along with another got to go to the Vancouver aquarium! Once we got there, our classes were separated and we got to explore the multitude of marine life that was present at the aquarium, across all their diverse exhibits. We went through the tropic zone and the Amazon, watching sharks zip by and the larger that life seas turtle Schoona gracefully swim without a care. We saw jellyfish contract and expand, floating around their exhibits, and the massive Arapaima that took me by surprise once I first found it. It took a lot of backtracking, but eventually we were able to find an answer for every question. After viewing lots of interesting and unique sea creatures, it was time to get lunch. Now that I had some sugar in me, I was feeling much better. It was around then we got to go to our seas lab, which was a truly informative and interesting experience. We got to learn about the scientific method, as well as begin able to handle lots of seas creatures, many of which we had learned about in class. The sea anemones and their sticky tentacles, the squishy sea cucumbers and the the prickly urchins. This hands on lab showed me a lot of marine life, and how important it is to keep it, for biological diversity and for other generations to have as well. After that the field trip was over, and it was time for us to go back home. The field trip was easily a great one, and we got to learn much about the marine world as well.