Vertebrates Emily Reiss Josie Jacob-Dolan Tori Willbanks-Roos

What makes a vertebrate a vertebrate? Internal bony skeleton Backbone encasing spinal column, skull-encased brain Deuterostomes (ex: Fish, amphibians, reptiles, birds, mammals)

Chordate- have a notochord and a dorsal, hollow nerve cord Chordate vs. Vertebrate Notochord Dorsal, Hollow Nerve cord Pharyngeal slits and clefts Muscular, post- anal tail Somites Tunicates Ex. humans, amphioxus Chordates are the more scientific name for vertebrates. In fact not all Chrodates do have a backbone, but they do have a notochord, the ancestor to the backbone.     In addition to the notochord all chordates have a hollow, dorsal, nerve chord, which is the ancestor to the central nervous system Pharyngeal Clefts-  series of pouches separated by grooves forms along the sides of the pharynx. In most chordates, these grooves develop into slits that open to the outside of the body Pharyngeal Slits- allow water entering the mouth to exit the body without passing through the entire digestive tract. Muscular, post-anal tail Often lost during enbryonic development Somites- blocks of mesoderm that form muscle segments,, which are found along each side of the notochord in all chordate embryos. Tunicates-(subphylum Urochordata) belong to the deepest–branching lineage of chordates. The tunicates most resemble other chordates during their larval stage, which may be as brief as a few minutes. Lancelets- (subphylum Cephalochordata) get their name from their bladelike shape. As larvae, lancelets develop a notochord, a dorsal, hollow nerve cord, numerous pharyngeal slits, and a post–anal tail. They feed on plankton in the water column, alternating between upward swimming and passive sinking. As they sink, they trap plankton and other suspended matter in their pharynx. Somites- blocks of mesoderm that form muscle segments,, which are found along each side of the notochord in all chordate embryos.

Craniates- chordates with a head Neural Crest Heart with at least 2 chambers Kidneys Evolved during the Cambrian explosion about 530 million years ago Ex. human, hagfish To be or not to be... All Craniates have a neural crest which is a collection of cells that appear in an embryo.  They disperse as the organism develops and turn into teeth, some bone and cartilage of the skull, the skin of the face, some neurons, and parts necessary for the development for the eyes   Hagfish the least derived craniate

Vertebrates- Craniates with a backbone Originally most vertebrae were cartilage In some cases additions to the notochord Most times surrounded the notochord Lampreys Ex. Humans, pteraspis   In some, the vertebrae were only little bits of cartilage along the notochord, but in most the vertebrae was enclosed the spinal cord and take over the mechanical roles of the notochord. Shark skeleton is made of cartilage, more flexible than a human lampreys- oldest living lineage of vertebrates pteraspis- jaw-less armored vertebrates

Gnathostomes- Vertebrates with jaws Gnathostome means "jaw mouth"  Aquatic gnathostomes have a lateral line system Appear in the fossil record about 470 million years ago Placoderms-"plate-skinned" Acanthodians Chondrichthyans-"cartilage fish"  These include sharks and rays Body structure/characteristics

 Rays vs Sharks Sharks streamlined body, swift swimmers; don't not maneuver very well movements of the trunk and the caudal (tail) fin help to move them are carnivores have several rows of teeth Oviparous vs. Ovoviviparous vs. Viviparous Rays  closely related to sharks  live on the bottom of the ocean  tails are whip-like -The largest sharks and rays are suspension feeders that consume plankton-

Gnathostomes- Vertebrates with jaws, continued. Osteichthyans- "bony fish" Most aquatic osteichthyans control their buoyancy with a swim bladder. They are covered by a protective bony flap called the operculum. page 682

Ray vs Lobe Finned fishes originated in fresh water and spread to the seas.  Some (salmon, sea–run trout) replay their evolutionary round–trip from fresh water to seawater and back to fresh water during their life cycle. serve as a food source for some humans ex: bass, trout, perch, tuna, and herring Lobe: rod–shaped bones surrounded by a thick layer of muscle in their pectoral and pelvic fins.  only three lineages survive today  ex: coelacanths, lungfishes, and  those that gave rise to tetrapods

Tetrapods- Gnathostomes that have limbs and feet Tetrapod means "four feet" Derived characters The Origin of Tetrapods ex: Amphibians- meaning: "two lives" Types on page 685

Amphibians Ancestors were tetrapods Moist skin Respiration: gas exchange through skin and lungs  Have a 3-chambered heart Ectotherms Reproduction: external fertilization, external development  Metamorphosis

Amniotes- Tetrapods that have a terrestrially adapted egg Amniotic egg  Extraembryonic membranes - specialized membranes, protect the embryo but not part of the embryo itself Different shells: more leathery and flexible (slows dehydration, allows for living on land) Came around in the Carboniferous Other adaptations: less permeable skin, ability to use the rib cage to ventilate the lungs.

Reptiles! Clade of amniotes, (lizards, snakes, turtles, crocs, birds.) Scales: create waterproof barrier, helps prevent dehydration  Shelled eggs on land "Cold blooded" Ectothermic- Not enough metabolic heat to have much effect on body temperature.  Endothermic- Warmed by heat generated by metabolism. Used to maintain body temperature higher than external environment.

Parareptiles- Mostly large, stocky quadrupedal herbivores Diapsids- Distinguished by pair of holes on each side of the skull, includes lepidosaurs and archosaurs. Lepidosaurs- Includes lizards, snakes, etc. Archosaurs- Includes crocodiles, alligators, dinosaurs, and birds. Pterosaurs- Winged reptile that lived during the time of dinosaurs. Dinosaurs-Member of an extremely diverse group of ancient reptiles varying in body shape, size, and habitat. Theropod- A member of an ancient group of dinosaurs that were bipedal carnivores.

Birds Reptiles but features all in adapted for flight. Wings, feathers, stronger muscles, good eye sight Better for hunting, migrating, defense  Endothermic Flightless species - Ratites (Ostrich, Kiwi, Emu, etc.) Beaks and feet very adaptable 

Mammals: Amniotes that have hair and produce milk Mammary glands - produce milk for offspring Hair - retain heat Endothermic  Teeth adapted for many different foods Bigger brains 

Marsupials Three major lineages: Monotremes Eutherians Synapsids Lacked hair, laid eggs Temporal Fenestra (holes behind eye sockets) - still present in humans Not true mammals but adapted mammal like characteristics Three major lineages: Monotremes Eutherians

 Eutherians: "Placental mammals" because placentas are more complex  Longer pregnancies, born when fully developed Includes Primates   Monotremes: Have hair, produce milk (from glands) Lay eggs (unlike any other mammal) Platypus, Echidnas (spiny anteaters)  Marsupials: Give birth to live young Embryo develops in placenta  Born early in development, matures in pouch

Primates Hands and feet, digits Opposable Thumb Big brains, flat faces Three main groups of living primates: Lemurs Lorises and Pottos Anthropoids Great Apes Humans

Works Cited Campbell, Neil A., and Jane B. Reece. Biology. 7th ed. San Francisco, CA: Pearson Education Inc, 2005. Print. Campbell, Neil A., and Jane B. Reece. Biology. 7th ed. San Francisco, CA: Pearson Education Inc, 2005. eBook.