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The integumentary system is the organ system that is made up of the skin, which can be hair, feather, nails, and scales. The integumentary system is vital to an organism because it acts as a shield and protects the organism from the outside environment like the weather, infectious organisms and acts as an touch and pain receptor. The integumentary system consists of three layers: the epidermis, dermis, and hypodermis.
The integumentary system is different for the four dissection animals. The earthworm has a moist, lubricated body to help it burrow through the earth. The crayfish has a hard exoskeleton, which really very different integumentary system than the other organisms, to protect itself from sharp objects and other predators. The grass frog has skin, which is waterproof to avoid water loss and dehydration. Lastly, the white rat has a short length of fur on the epidermis to aid it in maintaining homeostasis by regulating temperature.
The advantages of these varieties in the organisms depend on the environment they live in. For example, the grass frog has a moist waterproof layer of skin because it lives in a wet habitat such as a pond or lake. This allows it to move in the water and come up on dry land if needed. The skin allows enough water to osmose into and hydrate the body but keeps excess water out. Some disadvantages of moist skins are that organisms will need to stay near sources of water or else they will get dehydrated and die. The earthworm who lives underground relies on its moist skin to be able to move through the soil. It also has the ability to create lubricating liquid which helps it move. An advantage it has is because it's segmented, it is very flexible. However, the disadvantage is its size. Because the earthworm is so small and has little to no protection because of its thin layer of skin, it can easily be crushed by other animals. The crayfish relies on its hard exoskeleton shell for protection. It has tiny little hairs on its legs that can sense movements in the water. The disadvantage of the crayfish is that once the shell is gone, it will be exposed to danger and easily killed. The rat with its fur on top of a thin layer of skin can keep warm. It has whiskers on its snout and nails on its feet and the tail has rough hardened skin. A disadvantage could be wet fur can lower its body temperature. Also, with mouse traps like sticky ones, it can trap the rat because of its fur.
As evolution made changes, it required new forms of integumentary systems. The first forms of animals which were fish were cold-blooded and up to the reptiles, they all had either scales or moist skin. As the earliest animals, they lived in the water and their scales confined them to the water. The amphibians lived mostly on water but were able to come up to dry land but not for long. The first class of animals that were warm-blooded are birds. They needed a way to keep a temperature that is at their homeostatic level so they have feathers. This helped them keep warm and also allowed them to fly. In mammals, which are also warm-blooded, have fur or hair. This allows them to keep warm and maintain homeostasis. The disadvantages of furred animals are if there is a sudden change in weather like a heat wave, then thickly furred animals will die from the heat.
The integumentary system is a vital part of an organism which has its advantages and disadvantages depending on its environment.
Muscle and Skeletal System
The muscle system is the organ system which allows an organism to move. In vertebrates, the muscle system is controlled by the nervous system. There are three types of muscles which are: skeletal, cardiac, and heart muscles. The muscle system is very important to an organism because it provides strength, posture, and the ability to move for an organism.
The skeletal system is the reason why an animal has its form and shape. It also acts as a protective cage for all the important and vital organs in the body. Also, it allows organisms to move the way they do. There are three different kinds of skeletons. The first one is an endoskeleton. An animal with an endoskeleton has a skeleton inside its body like a human being. The second is an exoskeleton, which occurs in animals like crabs. Last is a hydro skeleton, where there isn't really a skeleton but is a fluid-filled cavity.
In our dissection animals, we can see that there are many differences in the animals muscle and skeletal system. The worm has a hydro skeleton body and it relies on its muscles to be able to move around by using muscular contraction. The worm has an advantage because it has a hydro skeleton which allows it to be very flexible. Evolution probably played a role in giving the earthworm an amazing ability. It has the power to regenerate lost segments in its body. It has great anabolic capabilities in its muscles, and in any case that it loses a couple of segments, then it can just regenerate it back. This can make up for its weak skeleton. Its disadvantages are it can easily be crushed because of its weak skeleton. In the crayfish, it has a exoskeleton which gives it good protection. Evolution played a role in making them have hard exoskeletons to survive in competitive waters. Also, because it has an exoskeleton it is an advantage and disadvantage. With its exoskeleton it has better protection but when it molts, it will be at its most vulnerable to predators and danger. The crayfish is divided into two segments: which are the abdomen and cephalothorax. It relies on its muscles in its eight legs used for moving around and a pair of strong pincers for getting food, attacking and defending itself. Also, it has a tail which is used to propel itself forward. The frog has a endoskeleton. It has long hind legs that allow to them to leap, jump, and swim away from danger. I believe that evolution has made frogs have strong powerful legs. Its long femur and powerful femur and tibias play a role in their survival. Last but not least, there is the rat which has a endoskeleton. The rat is similar to the frog but has smaller arm and leg bones and muscles. The rat relies on strong incisors and muscles for gnawing. Evolution played a role in rats because they must adapt to their food source. Therefore, they must have incisors which are accustomed to their food source.
One last thing is the differences between invertebrates and vertebrates. Invertebrates are animals which have no back bone and vertebrates do. The worm and crayfish are invertebrates while the frog and rat are vertebrates.
The muscle and skeletal system are important to organisms because they give them their form and shape and the ability to move. Also those two systems help them survive in their environments.
In all animals, the digestive system is an important system that breaks eaten food down into small enough pieces in order to diffuse into the cell and make feces as a way to get rid of the waste from digestion. This system is made up of the mouth, esophagus, stomach, and the small and large intestine, rectum, and lastly the anus.
Starting at the mouth when you smell the good food, your mouth will release an enzyme called salivary amylase that will lubricate the food so it will be able to go down the esophagus. After chewing and the food is drenched in the amylase, it will go down the esophagus. The esophagus is the tube like structure leading from the mouth to the stomach. The stomach is the organ that stores food, contains catabolic enzymes and produces acid to break down the food, and is responsible for killing microbes in the food we eat. When it leaves the stomach, the food would be in a liquid form and be able to enter the small intestine. There, the small intestine will finish the digestion process started by the stomach and further break the food down by the catabolic enzymes. Once the food is broken down into either disaccharides, fats, nucleic acids, or any smaller form, it will be absorbed and enter the blood stream straight into the cells to be used as energy. In the large intestine, any unabsorbed food, waste material, will be formed into feces. Also, it will reabsorb water and help create new "good" bacteria. Lastly, the feces will exit the body by the rectum, then out the anus into the environment.
In the earthworm, we see a difference in the digestive system. It has a mouth, esophagus, but a crop and gizzard. The crop is where the swallowed food are stored. The gizzard is where all the food are broken down. Because the earthworm has no teeth, it uses rocks that were swallowed and its strong muscles to break down the food. It goes through the rest of the digestive process and the feces exit through the anus. For the crayfish, it uses its mandible and maxillas to take food in. It goes through the esophagus and into the stomach. The crayfish' stomach is specialized to grind food up to be digested. It goes through the intestines, rectum, and lastly, out through the anus. In the frog, its long tongue snatches prey into its mouth, however it has weak maxillary teeth. It has the same digestive organs. The rat, has the same digestive organs as the frog. However, the liver is the largest organ in the rat.
I believe for the rat, evolution made the rats liver larger because as rats became situated in the industrial and urbanized environment, it had to adapt to the new food sources, like trash and dirty food. Therefore, the liver became important in order for the rat to safely eat the food and not get intoxicated or sick.
The digestive system is important to organisms because without them, there would be no way for them to survive as they won't be able to provide nutrients and energy to their cells.
The respiratory system is the system in animals which is responsible for bringing in fresh oxygen to the lungs and to breathe out carbon dioxide. This system is made up of the nose, mouth, trachea, bronchi, lungs and diaphragm. In fishes they contain gills, and in some organisms, they do not have any respiratory organs and use the skin to take in oxygen.
When animals breath in, oxygen would go into the nose then mouth. The air travels down the trachea and then into either the left or right bronchi then into the bronchiole tubes, which then leads into the lungs. The oxygen would then fill up tiny sacs called alveoli. As blood flows through the capillaries, oxygen will then diffuse into the blood, and carbon dioxide diffuses into the alveoli and travel out the respiratory system.
In our dissection animals, we see a variety of differences. In the earthworm, it does not possess any form of respiratory organs. It only takes in oxygen through the skin and in return expels carbon dioxide with the same method. In the crayfish, its gills are responsible for getting oxygen. Gills act as filters that pushes water out and trap the oxygen from the water. The oxygen is then able to diffuse into the bloodstream and the carbon dioxide diffuses out. For the grass frog, it works the same way as the earthworm. However, in its early stages of life which is being a tadpole, it has gills. In its adult stage, it will be able to use its lungs and also take in oxygen by absorbing oxygen through its skin. In the rat, it is similar to a human being. It will breathe in oxygen through its nose then go into the trachea, bronchi, bronchiole tube, into the lungs, in the alveoli, exchange gases, then the CO2 will exit out the system.
The differences in organs can relate to evolution. For example, when the frog evolved into its amphibious state, it needed to be able to breathe on land. Therefore, it went from gills, to lungs when it morphed into its adult stage. I don't think the earthworm and crayfish had any minor changes in their system because they have been on this planet for a long time and their environments do not require them to have any adaptations.
Therefore, the respiratory system is a vital system to organisms because they are responsible for taking and exchanging the gases oxygen and carbon dioxide in our body.
The circulatory system is responsible for circulating oxygenated blood throughout the body. The heart is the main organ which is responsible for this, and is also the second most vital organ in the body.
The process of which blood travels throughout the body is first entering the right atrium, then down into the right ventricle, then into the lungs. As oxygen diffuses into the un-oxygenated blood by passing the alveoli, it travels back into the left atrium and down the left ventricle then out into the aorta for the whole body.
In our dissection animals there are many differences in their circulatory system. The earthworm has five hearts in total. It has long blood vessels to carry blood throughout its body. In the crayfish, it only has one heart and is a two chambered heart. Blood vessels also bring blood throughout its body. In the frog, it has one heart and has three chambers. Blood vessels and arteries bring the blood throughout the body. Lastly, the white rat has one heart and is a four chambered heart. Blood vessels and arteries carry the blood throughout the body.
The advantages of the different chambered hearts are that the more chambers there are, the more oxygen will be available to the blood. The disadvantages are there is less oxygen available for the blood to carry; for example, the frog has a three chambered heart. In the ventricle, the oxygenated and un-oxygenated blood will get mixed and therefore, carry less oxygen. I think that evolution played a role in evolving the organism's hearts, because animals like the rat that require quick movement, needs more than two chambers to provide sufficient oxygen throughout the body to function at its best.
In conclusion, the circulatory is a vital organ in an organism which provides oxygenated blood throughout the body.