Phylum Chordata
Structures: They have four characteristics that distinguish them from their ancestors. They have a notochord, or a rod of vacuolated cells, encased by a firm sheath that lies ventral to the neural tube in vertebrate embryos and some adults. The second is a hollow nerve cord that lies dorsal to the notochord. Third is their pharyngeal pouches. The fourth one is a muscular post anal tail. They have a bilateral body plan. Chordates also develop spines from their notochord.
Body Covering/Support: Their notochord develops into the spine , and for aquatic species this helps them swim by flexing its tail. They have pharyngeal slits, that are opening in the pharnyzx that extend to the outside environment. In the aquatic species the slits allow water that enters the mouth during feeding to exit. They have tails which help aquatic species to move and help the terrestrial species helps with balance, courting and signaling when danger is near. They also have an inner skeleton with a backbone. It generally has four appendages that are formed ss legs , arms, wings or fins. They have a complex skin that is mostly covered with either feathers, scales or hair. Their color can be almost any color in nature. |
Respiration: Gills are present in tunicates and cephalochordates that serve in both feeding and respiration.The gills exchange gasses for the aquatic chordates. Amphibians use three types f respiration methods. When they are tadpoles they use their gills as they grow into land animals they develop lungs and use those or breath through their skin. Lungs that were already present in fish became the main organ of respiration in terrestrial vertebrates. Reptiles, birds and mammals use negative pressure breathing, where the muscles expand the lungs. They take oxygen through the nose or the mouth, through the pharynx to the trachea or the windpipe. For mammals and reptiles the trachea branches into the right and left bronchi, which ends in the alveoli, where the gas exchanges take place. The diaphragm expands the lungs in mammals and in reptiles muscles directly attached to the rib cage expand the lungs, this limits movement.
Nervous system: Their nervous system includes the brain, spinal cord and nerves. The brains of vertebrates are greatly developed, enlarged and are subdivided into functionally specialized regions. Most chordates have two eyes and at least a minimal system of hearing as fish do underwater. Some have very good hearing and can be completely blind like bats. |
Nutrition: Chordates pryon other animals or feed on plants to obtain their food. A chordate takes in food through the mouth. Their mouths have a muscular muscle called a tongue and some have teeth and some don't. Their digestive system includes a stomach, esophagus and intestines. Their food starts in the mouth and is grinded by teeth, for those who have teeth. Then it goes down a tube that starts at the mouth and ends at the anus. Salivary glands begin the digestion as the food moves towards the stomach through the esophagus. From the stomach the food then moves to the intestines where nutrients are absorbed and assimilated before waste is eliminated from the body.
Circulation of Nutrients: In the tunicates and vertebrates their blood is pumped by a heart but in cephalochordates, by the contraction of the blood vessels. Unoxygenated blood is carried forward with a vessel called the ventral aorta. It then goes through a series of branchial arteries in the gills, where gas exchanges take place, and the oxygenated blood flows to the body. The blood in vertebrates passes through tissue via capillaries. However, tunicates and cephalochordates don't have capillaries so the blood passes through spaces in tissues instead. The blood carries the nutrients and is pumped through the whole body, so it can obtain nutrients. Reproduction: Reproduction is mostly sexual,meaning the eggs are fertilized by sperm. However there are some members that reproduce asexually. For example some tunicates reproduce by budding off a part of themselves, and that bud develops into a new individuals. Some fish reproduce through parthenogenesis, where the embryo develops without being fertilized. Most chordates are dioecious meaning there are both males and females and some are hermaphroditic ,meaning they have both male and female reproductive organs; they can= self-fertilize.
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Mammalia Orders:
Carnivora: Most carnivores are terrestrial creatures. They have have strong sharp claws with no more than 5 and no less four toes on each foot. They have well developed canine teeth that generally have cutting edges. These features are good for hunting.
Carnivora: Most carnivores are terrestrial creatures. They have have strong sharp claws with no more than 5 and no less four toes on each foot. They have well developed canine teeth that generally have cutting edges. These features are good for hunting.
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Artiodactyla: Are hoofed animals, whose weight is borne equally by the third and fourth toes. They a presence or a absence of horns.
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Primates: They have hands, feet, shoulders, hips. They have large brains compared to other animals. They also have three-color vision. They also range in sizes.
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Rodentia: These are small rodents. They are gnawing animals whose incisors continue to grow throughout their lives. They have a gap between their front teeth.
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Cetacea: They have a fusiform-shaped body, that is large in size. They have no sebaceous glands. Their tails are flattened dorso-ventrally into flukes.
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