Chordata aldo michelle


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Chordata aldo michelle

  1. 1. CHORDATA<br />Michelle & Aldo<br />
  2. 2. Chordata…<br />Members of the Phylum Chordata include animals with which we are probably most likely familiar (including fish, birds, reptiles, amphibians and beasts like ourselves)<br />As unlikely as it seems, based on embryological evidence, the echinoderms appear to be the most-likely ancestors to the early chordates<br />Primitive stemmed echinoderms are thought to have shifted from arm-feeding to filter-feeding acquiring a body plan similar to urochordates<br />Unfortunately, the fossil record is poor and intermediates are lacking. The rest of the evolutionary picture is better documented. <br />
  3. 3. CHARACTERISTIC<br />Four structural characteristics set chordates apart from all other phyla: <br />a notochord<br />a pharyngeal gill slits<br />postanal tail<br />a hollow dorsal nerve cord<br />These attributes are always found in the larval forms or early embryo (although they may be absent in the adult). <br />
  4. 4. The Notochord<br />The notochord is mainly composed of fibrous connective tissue<br />For those animals in which it persists into the adult form, the notochord provides support (it acts like our backbone) and increases swimming efficiency<br />In animals like ourselves, bony structures called vertebrae develop near the notochord and eventually replace it during embryogenesis<br />
  5. 5. Pharyngeal Gill Slits<br />Pharyngeal gill slits are cuts in the pharynx that connect to a cavity surrounding the pharynx<br />For organisms in which they remain in the adult, they are often elaborated into respiratory structures (and are sometimes involved in filtering food during feeding).<br />The morphological equivalent of gill silts are seen briefly during our own development (weeks 4-5), but they usually close or develop into other structures<br />Occasionally, the slits do not close, resulting in the newborn having an opening in the neck area (a cervical fistula). <br />
  6. 6. In all the phyla we have studied up to this point, the anus was terminal (at the tip of the tail)<br />Chordates, on the other hand, follow the anus with a tail of variable length (again, an adaptation for locomotion).<br />In us, the tail is short and fused (the coccyx at the base of your spine). <br />The Postanal Tail<br />
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  9. 9. EXAMPLES<br />• sea squirts, lancelets, lamprey eels <br />• sharks, rays, trout, bass, tuna <br />• lungfish, frogs, salamanders <br />• snakes, lizards<br />• turtles, crocodiles, dinosaurs, birds <br />• mice, elephants, whales, dogs, people<br />
  10. 10. Phylum Chordata is divided into three subphyla:<br />Subphylum Urochordata<br />Subphylum Cephalochordata<br />Subphylum Vertebrata <br />
  11. 11. Subphylum Urochordata<br />
  12. 12. Subphylum Cephalochordata<br />
  13. 13. Subphylum Vertebrata<br />
  14. 14. Subphylum Vertebrata<br />Subphylum Vertebrata has several divisions you need to be familiar with:<br />SuperclassTetrapoda<br />Class Amphibia<br />Order Caudata – Tailed Amphibians; Salamanders; Newts<br />Order Anura – Tailless Amphibians; Frogs; Toads<br />Order Gymnophiona – Caecillians<br />Class Reptilia<br />Subclass Anapsida – Turtles; Tortoises<br />Subclass Diapsida – Crocodiles; Snakes; Lizards<br />Class Aves<br />Subclass Archaeornithes – Archaeopteryx (Extinct)<br />Subclass Neornithes – All Other Birds<br />Class Mammailia<br />Subclass Prototheria – Monotremes – Platypus; Echinda<br />Subclass Metatheria – Marsupials – Kangaroo; Koala<br />Subclass Eutheria – Placentals<br />
  15. 15. SuperclassTetrapoda<br />SuperclassTetrapoda has four major class divisions:<br />Class Amphibia<br />Class Reptilia<br />Class Aves<br />Class Mammailia<br />
  16. 16. ClassReptilia<br />Reptiles have acquired several advances over amphibians that have allowed them to move successfully into terrestrial habitats. <br />Their skin, for example, is more heavily thickened and is protected with surface scales that are impervious to water. <br />A reptile's scales are very different in structure from that of fish. The outer layer of skin is a thick layer of dead, keratin-filled cornified cells. These cells are organized into horny scales covering the entire outer surface. <br />Since reptiles have internal fertilization, water isn't even needed for mating. <br />
  17. 17. There are two major subclasses:<br />Subclass Anapsida – Turtles; Tortoises; some dinosaurs<br />Subclass Diapsida – Crocodiles; Snakes; Lizards; most dinosaurs<br />This is based on the presence or<br /> absence of certain temporal openings:<br />
  18. 18. Class Aves<br />The long hollow and porous bones of birds are thin and slender to aid in flight. Many bones overtime have fused together to give support. <br />Teeth have been lost and replaced by a light beak.<br />Feathers are cornified epidermal appendages that are probably related to scales. They are used for thermoregulation, communication, and as a flight surface.<br />There are two subclasses of Aves:<br />Subclass Archaeornithes (Extinct Archaeopteryx)<br />Subclass Neornithes(All other birds)<br />
  19. 19. Class Mammalia<br /> There are three subclasses based on birthing systems:<br />Subclass Prototheria<br /> (egg-laying monotremes)<br />Subclass Metatheria (marsupials)<br />Subclass Eutheria<br /> (placental)<br />
  20. 20. THANK <br />YOU!!! <br />