Overview: In these groups of labs we did many different dissections of all of the phyla. We learned many things through hands on work with all the different species. We also learned about the ecology of all the groups because there was a paragraph we had to summarize for each group.
Chordates
How did they Evolve Chordate species have changed greatly over geological time. An example of an adaption would be the development of the jaw, of paired appendages, including pectoral and pelvic fin or limb girdles. Adaptive radiation contributes to produce new species that are very similar in looks and behavior, but they are not closely related whatsoever. When this happens a trend is created which is called convergent evolution. How do they maintain body temp? Chordates that are cold blooded maintain their body temperature by moving to the areas that fits their needs. For example, if a cold blooded animal is hot, it will move to a shady, colder area. If it then gets cold, then it will most likely move to a sunny, warm area. Most warm blooded chordates maintain their body heat by regulating metabolic processes. There are many other methods of thermoregulation among warm blooded chordates How do Chordates feed, respire, excrete, circulate, move and respond? Feeding- Many chordates are filter feeders, these include tunicates and all lancelets. Vertebrates are adapted for feeding on much wider assortment of foods, this includes insects to large mammals. It can also include leaves, fruits, and seeds. Many mammal chordates have sharp teeth like a canine and incisors that help them tear and slice up their food. Respire-Aquatic chordates usually use gills for respiration. Land vertebrates use lungs for respiration. Although some chordates use both gills and lungs. Excrete-In nonvertebrate chordates gills and gill slits are an important feature when it comes to excretion. Many vertebrates however use kidneys, and excretory organs composed of small filtering tubes that remove waste from the blood. In tunicates waste leaves the body through the outflow siphons. Circulate-Chordates that use gills for respiration have a single-loop circulatory system. The blood travels from the heart to the gills , then to the rest of the body, and back to the heart in a single loop. Vertebrates that use lungs to breath have a double loop circulatory system. The first loop carries blood between the heart and lungs. Well healthy blood full of oxygen coming from the lungs returns to the heart. The second loop carries blood from the heart and is pumped to the body, while oxygen-poor blood from the body returns to the heart. Response-Nonvertebrate chordates gave a relatively simple nervous system with a mass of nerve cells that form a brain. Vertebrates have a more complex brain with a distinct regions, each with a different function. Movement-The skeletal system and muscular system supports a vertebrate’s body and make it possible to control movement. Vertebrates have a much easier time moving than nonvertebrate chordates. How fish feed,respire,circulate,excrete,respond? -Feeding Fish can be herbivores,carnivores, parasites, filter feeders, and detritus feeders. Fish are not limited to one of these categories, some can be many of them depending on what type of food is available. when the fish consumes food it passes through the esophagus to the stomach where it is broken down and made into energy. -Respire most fish use feather like gills located behind their head on either side of the body. they use this large surface area to make the exchange of of oxygen and carbon dioxide. this exchange process happens when the fish pull in oxygen rich water through their gills and push out the carbon dioxide. some fish such as lampreys and sharks have many gill openings, however most fish have only two covered by an operculum bone. other fish have lungs from which oxygen is supplied through the mouth and not through the gills. these fish need to go to the surface to get oxygen every so often so that they don't suffocate. -Circulation Fish have closed circulatory systems that pumps blood around the body and through the heart. they pump blood from the heart through the gills where the blood is oxygenated. The blood is then sent around the body to the brain, muscles, and digestive system. when the blood returns back to the heart it is pumped to the gills where the carbon dioxide is expelled through the respiration process. -Excrete Fishes rid themselves of nitrogenous waste through the gills and into the surrounding water. other waste is removed through the kidneys which are used to filter waste from blood. kidneys help fish control the amount of water in there body, salt water fishes lose water by osmosis so there kidneys try to concentrate waste and retain as much water as possible. freshwater fish excrete their waste through urine to retain as much water as possible, some fish can live in both environments by changing kidney function. -Response Fish have well developed nervous systems that consist of an olfactory bulb, cerebrum, optic lobe, cerebellum, medulla oblongata, and spinal cord. In addition fish have a nose to smell with and ears that they can’t hear with so they use their lateral lines to sense vibrations in the water. these vibrations can alert them to potential predators in their vicinity. Fishes Ecology of Fishes Some fishes spend their lives in the ocean and then move to fresh water to breed. Those fishes are called anadromous. For example salmon begin their lives in rivers, after one to four years they go back to where they were born. This trip takes up to several months. Some other fish go from their homes in fresh water and then breed in the ocean. These are called catadromous. Some examples of catadromous are eels which live their lives in rivers and then go to the ocean to breed. Groups of Fishes/Characteristics Jawless Fish: Jawless fishes don’t have teeth or jaws. Lack vertebrae and keep their notochords as adults. They are divided into two groups; lampreys and hagfishes. Lampreys are filter feeders as larvae and parasites as adults. Hagfishes have pinkish grey skin. They are worm like and have tentacles near the mouth area. Chondrichthyes: Consists of sharks, rays, and many different types of their relatives. Their structures are created from cartilage not of bones or anything else Bony Fish: Bony fish obviously have a bony infrastructure unlike Chondrichthyes or Jawless fish. Most of all common fish are bony. Amphibia Groups of Amphibians There are three different groups of amphibians. There are salamanders, frogs and toads, and caecilians. Most people know what frogs, toads, and salamanders are, but not many people know what caecilians. Caecilians are long, legless animals that live in water or burrow in moist soil. Ecology of Amphibians Amphibians have no feathers, fur, or scales this makes them easy prey for mammals and birds. However amphibians do have defenses to their predators such as, camouflage, bright coloration, and a skin gland that releases gross tasting, poisonous substance. Global amphibian population is declining and scientist aren't completely sure why this is happening. How did amphibians Evolve The first amphibians to cruise land were most likely similar to modern coelacanth. In order to adapt to land amphibians needed more than just legs. They have to breath air, protect their eggs from drying out, and they had to support themselves. How do they Maintain Body Heat Amphibians are cold blooded so they change body temperature depending on their surroundings. Often when they are too hot they go for a swim and cool down in the water. Once they start getting cold in the water, they might find a sunny spot to warm themselves up. |
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