Vertebrate 2
22. What are the teleostomi and why are they important? Is large group embracing the acanthodians , the bony fishes, and their tetrapod derivatives. Arising within these teleostomes are the teleosts, which today comprise most the living fishes.
32. Why are fishes major players in the vertebrate story? They outnumber all other vertebrates and one of the most successful groups of animals. Within the fish groups jaws and fins first appeared. Ray finned along with fleshy-finned fishes gave rise to land vertebrates, tetrapod's. Tetrapod's inherited paired appendages, jaws, backgrounds, and lungs from fishes.
33. Describe the features of early tetrapod's? First tetrapod's lives mostly in water but could use their formative limbs to navigate the shallow freshwater where they live and perhaps make and occasional sortie onto land. Tetrapod's underwent extensive radiation today's tetrapod's fully terrestrial vertebrates many amphibious, aquatic, and flying groups.
34. Describe labyrinthodonts? sckulls of juveniles carried the lateral line system, but absent in adults of the same species. And metamorphosis living terrestrial amphibians also lose the lateral line system of their aquatic larvae. Thus many ancient tetrapod's, like modern amphibians were probably aquatic as juveniles and terrestrial as adults. Ichthyostega, late Devonian, is a member of the ichtostedid amphibian group. The animal was about 1 cm long. Skelton of seymouria a later terrestrial anthracosaur from the early perimain was about 50 cm long.
35. What are the Lissamphibis including what animals they include common characteristics and where they stand in the vertebrate story? They arose from labyrinthodont radiation. Although many features such as enfolded labyrinthine teeth, have been lost. Three groups of living amphibians arise from within Lissamphibis and date back over 2 million years. The groups are frogs, salamanders, and caecilians. Amphibian eggs, will which lack shells and amniotic membranes, are laid in water or moist locations. External fertilization characterizes frogs whereas internal fertilization characterizes most salamanders and probably all caecilians. Typically, paired longs are present although they may be reduced or even absent entirely in some families of salamanders. Mucous glands of the skin keep amphibians moist and poison skin glands produce chemical unpleasant or toxic to predators. Modern amphibians in some ways in between fish and later tetrapod therefore they supply us with approximately living intermediates in the vertebrate transition from water to land.
40. What are amniotes and how have they radiated? Amniotes bear embryos enveloped in extraembryonic membranes. The embryo together with these membranes is usually packaged in a leathery shelled egg. Amniotic radiation is composed of two major lineages the Sauropsida and Synapsid. Sauropsida include birds, dinosaurs, modern reptiles. Synapsid produce many various forms including therapsids and modern mammals.
41. Describes skull fenestration among the amniotes. Differences among the schools occur in the temporal region behind the orbit. Two one or no fenestrae may be present and the position of the arch formed by postorbital and squamosal bone varies. The anapsid skull has no temporal fenestrae, first in the amniotes and the later turtles. The synapsid skull found in men million ancestors has a bar above its single temporal fenestrae. The diapsid skull has a bar between its to temporal fenestrae, this diverged from anapsid. The euryapsid skull, modified diapsid skull, has a bar below its single temporal fenestra. Rather than being a separate skull type, the euryapsid skull is thought to be derived from the diapsid skull that lost its lower temporal bar opening.
47. Explain eureptilian radiation? Three major lineages which built on diapid design. Lepidosauromorpha including fossils forms as well as snakes lizards and allies. Archosauromorpha including dinosaurs birds and related groups. Euryapsida includes marine reptiles,ichthyosaurs and sauropterygians.
60. Describe the groups Aves and where they came from. Birds outnumber all vertebrate except fishes. Birds are pretty much found everywhere. Among the extant amniotes, birds are almost closely related to crocodiles, and share many of the same basic features, despite their superficial differences. Both lay eggs encased in shells and have similar bone and muscle structure. If we take fossils into account it places the origin of birds within the Suarischia. This means birds are part of the dinosaur radiation. Evidence for this close association with dinosaurs comes especially from similarities in hip, wrist, and wishbone.
61. What makes birds unique? Birds unique due to their feathers, specializations of the skin. Some filamentous feathers were fluffy and down like, a few species had vaned feathers, flat and symmetrical feathers on both sides of the central shaft. These sorts was feathers would have been not suited for the power of flight which lead some to think that feathers arose initially as surface insulation, thermal regulation of body temperature. Whatever their initial biological roles, feathers evolved before birds.
67. Where did mammals arise from? Mammals arose within the therapsid radiation in the late Triassic, initially small and shrewd like. These Mesozoic mammals contended with a terrestrial fauns then dominated by dinosaurs. Most Mesozoic were shrew size and not much bigger than cat until the end of the Mesozoic era.
68. What are the characteristics associated with mammals? Hair, mammary glands, sebaceous glands, and red blood cells without nuclei are unique to living mammals. Other characteristics, that are not necessarily restricted to this class, include large brain in relation to body size, maintenance of high body temperature, and modifications of circulatory system from that of other amniotes.
69 describe early mammals. Early mammals were small for example the size of the shrew. Mammals were probably nocturnal and endothermic and most were equipped with sharp pointy teeth. Mammals brain size was larger for a given body size, then in their reptilian contemporaries. Instead of teeth that just snagged pray or cliped vegetation, mammals had variety of teeth that had specialized functions such as incisors, canines, premolars, and molars. Muscular cheeks Kept the food between tooth rows that chewed the food. Specialized tooth functions implies but does not prove that primitive mammals were endothermic. Early mammals are thought to have hatched from eggs and nursed from mammary glands like the monotremes.
71. What distinguishes eutherian and mammals? eutherian Mammals are today most numerous and widespread of any mammalian group. The nutritional and respiratory needs of the young are provided through the placenta, vascular in connecting fetus and the female uterus. A temporary placenta forms between the early embryo and female uterus and some marsupials. What distinguishes eutherian mammals is that reproduction in all species is based on a placenta.
74. Give an overview of vertebrates. Agnatha the vertebral column consists of a chain of vertebrae, segments a series of cartilage or bone blogs, and categorize the vertebrates. The earliest vertebrates were soft body from Cambrian-Haikouella and Hiakouichthys. Later ostracoderm were encased in protective shells of dermal bone. Today the only living representatives hagfish and lampreys. Jawless, the first vertebrates were likely limited in lifestyle until the invention of jaws. Gnathostomes evolution of jaw gave the earliest Gnathostomes equipment able to bite or crush prey. They also possess two sets of paired fins. Two major lines of evolution Chondrichthyes and the other Osteichthyes. Terapods arose within the sacropterygians and vertebrates moved to land for the first time. Amniotes arose within this early radiation of tetrapod, producing sauropsiod and synapsids. Sauropsiod would produce turtles, crocodiles and birds. The synapsids independently underwent own radiation leading to therapsids and modern mammals.
