Lecture chapter 34 verts 3 20 12 Phylum echinodermata Are divided into 6 classes spiny skin Deuterostomia Radial cleavage Coelom develops from out pockets of mesoderm enterocoelous Blastopore anus develops first 2 phylum 1st chordate 1st characteristics Ex Sea star sand dollars sea urchins sea cucumbers Endoskeleton consists of hard calcareous plate Bilaterians in larvae but adult form is mostly radial Water vascular system a network of water filled canals radiating into structures called tube feet a function in locomotion and feeding and gas exchange Phylum chordate Consists of 2 subphylum of inverts as well as the hagfishes and verts Shares features of embryonic development with echinoderms Overview half a billion years of backbone Phylum Chordata Deuterostomes Bilateral 2 subphylum which are inverts I urochordata tunicates II Cephalochordate lancelets Key features Notochord Dorsal hollow nerve cord Pharyngeal gill slits Post anal tail Vertebrates Cambrian explosion I 530 mya II Appearance of chordate which gave rise to verts III Verts have been some of most successful on planet Around 52 000 species Cont phylum chordate All have set of derived characteristics Some only possess during embryonic development Subphylum urochordata tunicates Marine suspension feeders commonly called sea squirts Tunicates most resemble chordates during larval stage but look completely different as adult because connect to object and become sessile Subphylum cephalochordate lancelets Named for blade like shape Marine suspension feeders retain body plan as adults Derived characteristics of craniates includes Myxini hagfish Infraphylum verts Lamprays Cartiaginious fishes Body fishes Amphibians Reptiles and birds Mammals Cranium skull protects the brain or central nervous system Have higher metabolism Have a heart with at least 2 chambers as well as red blood cells with hemoglobin Have kidneys Hagfishes not included in verts Slime glands Feed on dead or dying prey Jawless marine craniates Contain cartilaginous skull and axial rod of cartilage derived from notochord Lack of vertebrae Subphylum vertebrata lamprays class petromyzontida Jawless Oldest living lineage of vert Freshwater can be parasitic or marine parasitic Conodonts were 1st vertebrates with mineralized skeletal elements in their mouth and pharynx Lecture chapter 34 Verts 3 22 12 Gnathostomes are verts that have jaws Chondrichthans sharks rays and relatives Large liver 30 of body mass filled with squleen oil The largest and most diverse subclass of chondrichthyes Includes the sharks and rays A second subclass Is composed of a few dozen species of ratfishes General body plan for Osteichthyes Fishes breathe by drawing water over four or five pairs of gills Located in chambers covered by a protective bony flap called the operculum Ray finned fishes class Actinopterygii Ray finned fishes class act include nearly all the familiar aquatic Osteichthyes The fins supported mainly by long flexible rays are modified for maneuvering defense and other functions Lobe fins Class Sarcopterygii The lobe0fin fishes class Sarcopterygii Have muscular and pectoral fins Include coelacanths lungfishes and tetrapods Tetrapods one lineage of lobe fins the fins became progressively more limb like while the rest of the body retained adaptations for aquatic life amphibians Class Amphibia amphibians are represented by about 6 150 species of organisms in 3 orders most amphibians have moist skin that complement the lungs in gas exchange diversity of amphibians order Urodela includes salamanders which has tails as adults order Anura includes frogs and toads which lack tails as adults order Apoda includes caecilians which are legless burrowing amphibians and resemble worms Amniotes are tetrapods that have a terrestrially adapted egg Figure 34 24 Amniotic egg the extraembryonic membranes are the amnion chorion yolk sac and allantois Reptiles The reptile clade includes The tuatara lizards snakes turtles crocodilians birds and the extinct dinosaurs Reptiles Class Reptilia Have scales that create a waterproof barrier Lay shelled eggs on land Turtles Anapsida Al turtles have a boxlike shell Made of upper and lower shields that are fused to the vertebrae clavicles and ribs Lepidosaurs tuatars lizards snakes turtles One surviving lineage of lepidosaurs is represented by 2 species of lizard like reptiles called Tuatara The other major living lineage of lepidosaurs are the Squamates the lizards and snakes Lizards are the most numerous and diverse reptiles apart from birds T snakes are legless lepidosaurs that evolved from lizards Archosaurs Crocodilians Pterosaurs Dinosaurs They includes bipedal carnivores called theropods T rex Paleontologists have also discovered signs of parental care among dinosaurs Alligators and crocodiles Crocodilians belong to an archosaur lineage that dates to the late Triassic Birds living Archosaurs adapted for flight Origin or birds Birds probably descended from theropods A group of small carnivorous dinosaurs By 150 mya Feathered theropods have evolved into birds Archaeopteryx Remains the oldest bird known Living birds The ratites Are all flightless The demands of flight have rendered the general body form of many flying birds similar to one another Lecture chapter 34 verts 3 27 12 Mammals are amniotes that have hair and produce milk Mammals class Mammalia are represented by more than 5 300 species Mammals have Mammary glands which produce milk Hair A larger brain than other vertebrates of equivalent size Differentiated teeth Monotremes are a small group of egg laying mammals consisting of echidnas and the platypus Marsupials Include opossums kangaroos and koalas A marsupial is born very early in its development and completes its embryonic development while nursing within a maternal pouch called a marsupium Eutherians placental mammals Compared to marsupials Eutherians have a longer period of pregnancy Young eutherians complete their embryonic development within a uterus joined to the mother by the placenta 14 major eutherians orders pg 725 You should know List the derived traits for chordates craniates vertebrates Gnathostomes tetrapods amniotes birds mammals primates humans Describe the trends in mineralized structures in early vertebrates Describe and distinguish between Chondrichthyes and Osteichthyes noting the main traits of each group Define and distinguish among Gnathostomes tetrapods and amniotes Describe an amniotic egg and explain its