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The earliest vertebrates that diverged from the invertebrate chordates were the jawless fishes. Fishes with jaws (gnathostomes) evolved later. Jaws allowed early gnathostomes to exploit new food sources. Agnathans include the hagfishes and lampreys. Hagfishes are eel-like scavengers that feed on dead invertebrates and ...
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As tetrapods, most amphibians are characterized by four well-developed limbs, although some species of salamanders and all caecilians are limbless. The most important characteristic of extant amphibians is a moist, permeable skin used for cutaneous respiration. The fossil record provides evidence of amphibian species, ...
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The amniotes are distinguished from amphibians by the presence of a terrestrially adapted egg protected by amniotic membranes. The amniotes include reptiles, birds, and mammals. The early amniotes diverged into two main lines soon after the first amniotes arose. The initial split was into synapsids (mammals) and saurop...
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Birds are endothermic, meaning they produce their own body heat and regulate their internal temperature independently of the external temperature. Feathers not only act as insulation but also allow for flight, providing lift with secondary feathers and thrust with primary feathers. Pneumatic bones are bones that are ho...
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Mammals in general are vertebrates that possess hair and mammary glands. The mammalian integument includes various secretory glands, including sebaceous glands, eccrine glands, apocrine glands, and mammary glands. Mammals are synapsids, meaning that they have a single opening in the skull. A key characteristic of synap...
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All primate species possess adaptations for climbing trees, as they all probably descended from tree-dwellers, although not all species are arboreal. Other characteristics of primates are brains that are larger than those of other mammals, claws that have been modified into flattened nails, typically only one young per...
https://openstax.org/books/biology/pages/29-chapter-summary
Acanthostega : one of the earliest known tetrapods
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Actinopterygii : ray-finned fishes
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allantois : membrane of the egg that stores nitrogenous wastes produced by the embryo; also facilitates respiration
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amnion : membrane of the egg that protects the embryo from mechanical shock and prevents dehydration
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amniote : animal that produces a terrestrially adapted egg protected by amniotic membranes
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Amphibia : frogs, salamanders, and caecilians
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ampulla of Lorenzini : sensory organ that allows sharks to detect electromagnetic fields produced by living things
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anapsid : animal having no temporal fenestrae in the cranium
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anthropoid : monkeys, apes, and humans
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Anura : frogs
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apocrine gland : scent gland that secretes substances that are used for chemical communication
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Apoda : caecilians
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Archaeopteryx : transition species from dinosaur to bird from the Jurassic period
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archosaur : modern crocodilian or bird, or an extinct pterosaur or dinosaur
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Australopithecus : genus of hominins that evolved in eastern Africa approximately 4 million years ago
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brachiation : movement through trees branches via suspension from the arms
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brumation : period of much reduced metabolism and torpor that occurs in any ectotherm in cold weather
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caecilian : legless amphibian that belongs to the clade Apoda
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Casineria : one of the oldest known amniotes; had both amphibian and reptilian characteristics
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Catarrhini : clade of Old World monkeys
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Cephalochordata : chordate clade whose members possess a notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail in the adult stage
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Chondrichthyes : jawed fish with paired fins and a skeleton made of cartilage
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Chordata : phylum of animals distinguished by their possession of a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some point during their development
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chorion : membrane of the egg that surrounds the embryo and yolk sac
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contour feather : feather that creates an aerodynamic surface for efficient flight
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Craniata : clade composed of chordates that possess a cranium; includes Vertebrata together with hagfishes
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cranium : bony, cartilaginous, or fibrous structure surrounding the brain, jaw, and facial bones
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Crocodilia : crocodiles and alligators
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cutaneous respiration : gas exchange through the skin
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dentary : single bone that comprises the lower jaw of mammals
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diapsid : animal having two temporal fenestrae in the cranium
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diphyodont : refers to the possession of two sets of teeth in a lifetime
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dorsal hollow nerve cord : hollow, tubular structure derived from ectoderm, which is located dorsal to the notochord in chordates
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down feather : feather specialized for insulation
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eccrine gland : sweat gland
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Enantiornithes : dominant bird group during the Cretaceous period
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eutherian mammal : mammal that possesses a complex placenta, which connects a fetus to the mother; sometimes called placental mammals
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flight feather : feather specialized for flight
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frog : tail-less amphibian that belongs to the clade Anura
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furcula : wishbone formed by the fusing of the clavicles
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gnathostome : jawed fish
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Gorilla : genus of gorillas
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hagfish : eel-like jawless fish that live on the ocean floor and are scavengers
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heterodont tooth : different types of teeth that are modified for different purposes
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hominin : species that are more closely related to humans than chimpanzees
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hominoid : pertaining to great apes and humans
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Homo : genus of humans
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Homo sapiens sapiens : anatomically modern humans
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Hylobatidae : family of gibbons
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Hylonomus : one of the earliest reptiles
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lamprey : jawless fish characterized by a toothed, funnel-like, sucking mouth
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lancelet : member of Cephalochordata; named for its blade-like shape
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lateral line : sense organ that runs the length of a fish’s body; used to detect vibration in the water
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lepidosaur : modern lizards, snakes, and tuataras
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mammal : one of the groups of endothermic vertebrates that possesses hair and mammary glands
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mammary gland : in female mammals, a gland that produces milk for newborns
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marsupial : one of the groups of mammals that includes the kangaroo, koala, bandicoot, Tasmanian devil, and several other species; young develop within a pouch
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monotreme : egg-laying mammal
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Myxini : hagfishes
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Neognathae : birds other than the Paleognathae
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Neornithes : modern birds
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notochord : flexible, rod-shaped support structure that is found in the embryonic stage of all chordates and in the adult stage of some chordates
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Ornithorhynchidae : clade that includes the duck-billed platypus
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Osteichthyes : bony fish
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ostracoderm : one of the earliest jawless fish covered in bone
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Paleognathae : ratites; flightless birds, including ostriches and emus
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Pan : genus of chimpanzees and bonobos
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Petromyzontidae : clade of lampreys
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pharyngeal slit : opening in the pharynx
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Platyrrhini : clade of New World monkeys
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Plesiadapis : oldest known primate-like mammal
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pneumatic bone : air-filled bone
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Pongo : genus of orangutans
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post-anal tail : muscular, posterior elongation of the body extending beyond the anus in chordates
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primary feather : feather located at the tip of the wing that provides thrust
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Primates : order of lemurs, tarsiers, monkeys, apes, and humans
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prognathic jaw : long jaw
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prosimian : division of primates that includes bush babies of Africa, lemurs of Madagascar, and lorises, pottos, and tarsiers of Southeast Asia
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salamander : tailed amphibian that belongs to the clade Urodela
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Sarcopterygii : lobe-finned fish
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sauropsid : reptile or bird
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sebaceous gland : in mammals, a skin gland that produce a lipid mixture calledsebum
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secondary feather : feather located at the base of the wing that provides lift
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Sphenodontia : clade of tuataras
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Squamata : clade of lizards and snakes
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stereoscopic vision : two overlapping fields of vision from the eyes that produces depth perception
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swim bladder : in fishes, a gas filled organ that helps to control the buoyancy of the fish
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synapsid : mammal having one temporal fenestra
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Tachyglossidae : clade that includes the echidna or spiny anteater
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tadpole : larval stage of a frog
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temporal fenestra : non-orbital opening in the skull that may allow muscles to expand and lengthen
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Testudines : order of turtles
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tetrapod : phylogenetic reference to an organism with a four-footed evolutionary history; includes amphibians, reptiles, birds, and mammals
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theropod : dinosaur group ancestral to birds
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