Dissections
This following section of my website will show the dissections that my class did at the very beginning of the semester. These were very interesting to perform, and I learned a lot during this unit in Biology/Biotechnology. This unit also intertwined with our upcoming ecology unit.
Ecology is the branch of biology that deals with the relations of organisms to one another and to their physical surroundings. This has been an ongoing unit in our STEM course since the beginning of the year. We have applied many real life situations to what we have done in class. These dissections are just a small part of what we studied.
Ecology is the branch of biology that deals with the relations of organisms to one another and to their physical surroundings. This has been an ongoing unit in our STEM course since the beginning of the year. We have applied many real life situations to what we have done in class. These dissections are just a small part of what we studied.
Domain Eukarya Kingdom Protista Lab
During this lab, we looked at several different kinds of protists. The one pictured above is "protozoa", a protist we observed in class. The protists we looked at were Euglena, Paramecium, Vorticella, Amoeba, and Protozoa. The main the functions of protists are nutrient gathering, reproduction, and respiration acquisition.
We observed these organisms under a light microscope on already prepared slides. We went through every protist and observed them under 40x, 400x, and 1000x magnification levels. Here are my findings for each of the protists we observed in class.
The Euglena was the first organism myself and my partner observed. There were several structures that made up this organism, and they were very spread out. In our observation, we noticed that there was a small cluster of these structures. These structures were also transparent. Observing these structures worked best under 40x magnification.
The Paramecium, or paramecium culture we used, was seemingly transparent. The structures were spread out over the slide, and they were all individual. On most of the structures, we noticed a darker spot in the center of the specimen.
The Amoeba was blue, and like the Paramecium, consisted of spread out individual structures. Some of these structures had dark centers, but this does not go for all of them. The structures also had an irregular shape to them.
The Vorticella was the most fascinating to look at in my opinion. My partner and I both agreed that we thought it oddly resembled the look of muscle. Vorticella consisted of one large structure, and as a whole was red. There was the occasional dark spot on the specimen as well. Vorticella also looked like there were individual sinews on it.
Ecology of protists: Protists are found in many forms, with different backgrounds in ecology. For example, some protists are unicellular, others are colonial, and some are multicellular. Protists are mainly decomposers, and they play a key role in the food chain, as well as the ecosystems in which they reside. Protists live in a variety of habitats. Many are aquatic, such as protozoans. Some are parasites. Protists not only have a huge effect on the animal population, but on humans as well.
We observed these organisms under a light microscope on already prepared slides. We went through every protist and observed them under 40x, 400x, and 1000x magnification levels. Here are my findings for each of the protists we observed in class.
The Euglena was the first organism myself and my partner observed. There were several structures that made up this organism, and they were very spread out. In our observation, we noticed that there was a small cluster of these structures. These structures were also transparent. Observing these structures worked best under 40x magnification.
The Paramecium, or paramecium culture we used, was seemingly transparent. The structures were spread out over the slide, and they were all individual. On most of the structures, we noticed a darker spot in the center of the specimen.
The Amoeba was blue, and like the Paramecium, consisted of spread out individual structures. Some of these structures had dark centers, but this does not go for all of them. The structures also had an irregular shape to them.
The Vorticella was the most fascinating to look at in my opinion. My partner and I both agreed that we thought it oddly resembled the look of muscle. Vorticella consisted of one large structure, and as a whole was red. There was the occasional dark spot on the specimen as well. Vorticella also looked like there were individual sinews on it.
Ecology of protists: Protists are found in many forms, with different backgrounds in ecology. For example, some protists are unicellular, others are colonial, and some are multicellular. Protists are mainly decomposers, and they play a key role in the food chain, as well as the ecosystems in which they reside. Protists live in a variety of habitats. Many are aquatic, such as protozoans. Some are parasites. Protists not only have a huge effect on the animal population, but on humans as well.
Sponge
Our next dissection was the sponge. The sponge we dissected was "Grantia", also known as the "simple sponge". These sponges belong to the subkingdom of Porifera. This sponge is such a simple specimen, that it was given it's own class. What makes this organism so simple, is its lack of distinct organ systems.
The sponges we observed were very "slug-like". They had a very irregular, oval shape to them, and were a light yellow/brown. The form of sponges is influenced by the available strength and water movements of their surroundings. The first step in this dissection was to make a horizontal cut through the midsection of the organism. We observed the spongcoel by using a fine point probe before opening up the hollow center cavity. We observed the 3 types of skeletal material found in the sponge: the calcareous spicules, siliceous spicules, and the spongin network of bath sponge. We then observed the choanocyte, the heart of the water system in the simple sponge. The function of the choanocyte is to create a water current inside the sponge.
Ecology of "Grantia": Sponges are aquatic creatures. They don't move, but are carried by the current and are often found near the sea shore. This is how they reproduce. Sponges release their spores into the open water, and the spores are then carried away by the current. To get rid of waste, sponges have a filter chamber. Since sponges have no digestive tract or kidney, this is their only means of getting rid of waste. To gain energy and nutrients they eat amoebocytes.
The sponges we observed were very "slug-like". They had a very irregular, oval shape to them, and were a light yellow/brown. The form of sponges is influenced by the available strength and water movements of their surroundings. The first step in this dissection was to make a horizontal cut through the midsection of the organism. We observed the spongcoel by using a fine point probe before opening up the hollow center cavity. We observed the 3 types of skeletal material found in the sponge: the calcareous spicules, siliceous spicules, and the spongin network of bath sponge. We then observed the choanocyte, the heart of the water system in the simple sponge. The function of the choanocyte is to create a water current inside the sponge.
Ecology of "Grantia": Sponges are aquatic creatures. They don't move, but are carried by the current and are often found near the sea shore. This is how they reproduce. Sponges release their spores into the open water, and the spores are then carried away by the current. To get rid of waste, sponges have a filter chamber. Since sponges have no digestive tract or kidney, this is their only means of getting rid of waste. To gain energy and nutrients they eat amoebocytes.
Jellyfish
We now come to the jellyfish, also known as Cnideria. Like the past dissections, we used a dissecting microscope to accurately observe these creatures. Jellyfish come in two forms; medusa and polyp. The jellyfish that we dissected was in the medusa body plan. This means that the body is shaped like a bell. The convex portion represents the aboral surface, while the oral surface is concave.
Members of this phylum, Cnideria, have two tissue layers, an outer epidermis and an inner gastrodermis. A noncellular matrix makes up the majority of this animal. The function of this matrix is to store nutrients and is a site for gas exchange. Jellyfish have an incomplete digestive system as well. This means that food comes in through the mouth, gets digested, then the waste exits through the mouth. It was difficult to observe this in the process of the dissection. My partner and I then observed the manubrium, a tube that hangs down from the mouth of the animal. The manubrium can be observed as a darker square in the gastrovascular cavity. We could also observe the many tentacles, which are used for capturing and immobilizing prey.
Ecology of the jellyfish: Cniderians are the builders of some of the richest and most complex ecosystems on the planet, famously known for their role in the ecosystems of coral reefs. Other cnidarians are important as predators in the open ocean. However, many Cniderians, depends on single-celled protists that live within the animal's tissues to survive.
Members of this phylum, Cnideria, have two tissue layers, an outer epidermis and an inner gastrodermis. A noncellular matrix makes up the majority of this animal. The function of this matrix is to store nutrients and is a site for gas exchange. Jellyfish have an incomplete digestive system as well. This means that food comes in through the mouth, gets digested, then the waste exits through the mouth. It was difficult to observe this in the process of the dissection. My partner and I then observed the manubrium, a tube that hangs down from the mouth of the animal. The manubrium can be observed as a darker square in the gastrovascular cavity. We could also observe the many tentacles, which are used for capturing and immobilizing prey.
Ecology of the jellyfish: Cniderians are the builders of some of the richest and most complex ecosystems on the planet, famously known for their role in the ecosystems of coral reefs. Other cnidarians are important as predators in the open ocean. However, many Cniderians, depends on single-celled protists that live within the animal's tissues to survive.
Squid
Compared to Cnideria and the other dissected specimens, the squid is extremely, extremely complex. The overall shape of the animal allows it to move quickly and efficiently through the water. This is thanks to a pair of fins and its elongated body plan. The main body of the squid is made up of the body tube or "mantle". The leather-like covering protects its soft body. This covering is called the visceral mass. We noticed while dissecting the squid, that its two eyes look incredibly similar to that of a vertebrate. The squid has 10 appendages in total; 8 arms and 2 long tentacles. These appendages are what's known as the molluscan foot. We observed the suckers on each of the arms by placing them under the dissecting microscope. The mouth is located at the base of the arms and tentacles and has two beak-like structures. To be able to see them clearly, we had to pull the arms away from the head and pinch the head from both sides to expose the beak properly. To view the internal anatomy of the squid, we made an incision along the mantle and towards the end of the creature. We observed the liver, siphon, esophagus and ink sac. The purpose of the ink sac is to allow for a quick escape when the squid is in danger.
Ecology of squid: Squids are an important component of many marine ecosystems where ever they are. Squids play an important role as both predators and prey of marine mammals, birds, and other fish. Whether that be for population purposes or more. They are truly fantastic creatures that are a huge benefit to the environment and the ecosystems around them.
Ecology of squid: Squids are an important component of many marine ecosystems where ever they are. Squids play an important role as both predators and prey of marine mammals, birds, and other fish. Whether that be for population purposes or more. They are truly fantastic creatures that are a huge benefit to the environment and the ecosystems around them.
Earthworm
During the earthworm dissection we mainly observed the reproduction and digestive systems. The reproduction system in the worm is something completely different from what we've observed in any other specimen we've dissected. This is due to the fact that earthworms are asexual beings. The digestive system though, is very similar to what we saw in the squid, grasshopper, frog, etc...
We started the dissection by locating the exterior and posterior ends of the worm. We could tell which end was which because the anterior end is somewhat larger than that of the posterior. After this, we counted all the segments on the worm; on our worm we counted over 100. We then placed the worm under a dissecting microscope so we could see the small excretory pores on each segment. Counting from the anterior, my partner and I could identify the openings to the oviducts, the female pores that release eggs. Those were found on segment 14. On segment 15, the sperm ducts were found. After observing all the exterior features we could, we proceeded to cut the worm down the center, being careful not to go too deep and cut into the digestive system. We went through and identified each vesicle, vessel, etc..
Ecology of the earthworm: Earthworms play an amazingly important role in the ecosystem we know so well. Earthworms are decomposers, and can be found almost any where. They work very quickly to decompose the matter in front of them, whether that be soil or compost. Earthworms are incredibly beneficial to us and the environment. They serve a variety of purposes for us, such as producing fresh soil for gardens or breaking down old, decaying matter.
We started the dissection by locating the exterior and posterior ends of the worm. We could tell which end was which because the anterior end is somewhat larger than that of the posterior. After this, we counted all the segments on the worm; on our worm we counted over 100. We then placed the worm under a dissecting microscope so we could see the small excretory pores on each segment. Counting from the anterior, my partner and I could identify the openings to the oviducts, the female pores that release eggs. Those were found on segment 14. On segment 15, the sperm ducts were found. After observing all the exterior features we could, we proceeded to cut the worm down the center, being careful not to go too deep and cut into the digestive system. We went through and identified each vesicle, vessel, etc..
Ecology of the earthworm: Earthworms play an amazingly important role in the ecosystem we know so well. Earthworms are decomposers, and can be found almost any where. They work very quickly to decompose the matter in front of them, whether that be soil or compost. Earthworms are incredibly beneficial to us and the environment. They serve a variety of purposes for us, such as producing fresh soil for gardens or breaking down old, decaying matter.
Grasshopper
The grasshopper pictured above is an arthropod. Arthropods have jointed appendages, segmented bodies, and an exoskeleton. We made al these observations while doing this dissection. Grasshoppers have three main body regions; the head, thorax, and abdomen. There are three legs attached to the thorax, a single pair of antenna attached to the head, two pairs of wings, and mouthparts adapted for chewing/sucking. It's clear that the legs of this insect are adapted for the earth. Digging, jumping, crawling, or swimming are the main functions of these limbs. We also studied the eyes of this specimen. Grasshoppers have compound eyes, as well as 3 eyes called ocelli that are located between the compound ones. The mouth consists of the upper lip (labrum), jaws (mandibles), the maxille used to cut or hold food, and the lower lip (labium).
We then continued with the dissection by removing each of the appendages and studying them individually.
Ecology of the grasshopper: Grasshoppers are an important part of the North American rangeland ecosystem and an important factor in the economies that derive from the rangeland. Most of the ecology of the grasshopper revolves around its immense population. Grasshoppers are an important native component of grassland ecosystems in the U.S., playing a role in nutrient cycling and serving as a critical food supply for wildlife.
We then continued with the dissection by removing each of the appendages and studying them individually.
Ecology of the grasshopper: Grasshoppers are an important part of the North American rangeland ecosystem and an important factor in the economies that derive from the rangeland. Most of the ecology of the grasshopper revolves around its immense population. Grasshoppers are an important native component of grassland ecosystems in the U.S., playing a role in nutrient cycling and serving as a critical food supply for wildlife.
Perch was the only kind of fish we dissected this year. A perch is a typical, bony fish. It was our job to observe the internal and external anatomies of them. We started out easy. We identified the fins; the anterior dorsal fin (found on top of the fish), the posterior dorsal fin (found behind the anterior dorsal fin), the pectoral and pelvic fin, the anal fin (found on bottom of fish), and the caudal fin (found at the back of the fish, used for direction etc...). The first step was to observe the movement of the jaws, and to examine the gill arches and the gill filaments. The first actual cut we made was across the lateral line of the fish, the faint line that runs along its body. We kept cutting until we had made a square incision (can be seen above). We lifted away the cut section to reveal the structures beneath. We then proceeded to observe the digestive, reproduction, respiratory, excretory, and circulatory systems of the fish.
Ecology of perch: Fish make up the largest population of vertebrates found in fresh and salt water. 25,000 species of fish make up 50% of the total vertebrate population. These perch are hardy and adaptable. They are most commonly found in lakes, slow moving streams etc... They are strictly carnivorous, consuming small fishes, aquatic insects, crayfish, and snails. This regulates population growth, and its obvious that in these ecosystems, perch are very important.
Ecology of perch: Fish make up the largest population of vertebrates found in fresh and salt water. 25,000 species of fish make up 50% of the total vertebrate population. These perch are hardy and adaptable. They are most commonly found in lakes, slow moving streams etc... They are strictly carnivorous, consuming small fishes, aquatic insects, crayfish, and snails. This regulates population growth, and its obvious that in these ecosystems, perch are very important.
Frog
Almost everyone who has gone through biology at one point or another has dissected a frog. We mainly focused on identifying the digestive structures inside of it. We started by making a vertical cut along the body as shown above. Once that was done, we pinned down the skin of the frog to the dissection tray. This way we could get a clear look at the digestive system. It was easy to identify the heart and intestines, which obviously serve the same purpose as ours. It was much harder however, to identify the lobes of the liver. During this dissection I learned that a frog has 3 lobes of liver; the right lobe, the left anterior lobe, and the left posterior lobe. It was also difficult to find the mesentery, which is the membrane that holds the small intestine together. We traced the digestive system down to the gall bladder, bladder, and cloaca. The gall bladder stores bile, which allows the frog to float or dive as it pleases. The large intestine leads to the cloaca, and the bladder itself is self-explanatory.
Ecology of frogs: Frogs play a central role in many ecosystems. They control the insect population, and they're a food source for many larger animals. This keeps things in balance for the most part. Frogs are also ectothermic, meaning they rely on the temperature of the environment around them to control their body temperature. Everything intertwines when it comes to ecosystems, which can be accurately observed with frogs.
Ecology of frogs: Frogs play a central role in many ecosystems. They control the insect population, and they're a food source for many larger animals. This keeps things in balance for the most part. Frogs are also ectothermic, meaning they rely on the temperature of the environment around them to control their body temperature. Everything intertwines when it comes to ecosystems, which can be accurately observed with frogs.