BIOS
W2L2 Biodiversity II.pdf

Lungfish lungfish are more closely related to

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Lungfish Lungfish are more closely related to tetrapods than to coelacanths Important predators during the Devonian Six species, all in stagnant swamps & muddy waters of South America, Africa, and Australia Lungs in lungfish evolved from a gas-filled sac that extended from the esophagus of the common ancestor of bony fish (Osteichthyes = Actinopterygii + Sarcopterygii). In bony fishes, this sac evolved into a swim bladder. Lungs in lungfish are homologous to lungs in tetrapods 149 Need to know Chordates Tetrapoda Sarcopterygii Strictly speaking, this tree is of the “craniates”; Chordates include a few other groups that branch off at the base of this tree, such as the group that includes the lancelets 150 Tetrapoda Tetrapods are the 4-legged animals, including amphibians, mammals, and reptiles (including snakes and other legless forms, because they once had legs) Evolved from a lobe-finned ancestor 151
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Amphibians Includes frogs, salamanders, and a tropical legless group known as caecilians Moist skin (no scales) Egg composed of a series of jellylike layers, somewhat like a fish egg. Eggs must remain moist 152 Need to know Chordates Tetrapoda Sarcopterygii Strictly speaking, this tree is of the “craniates”; Chordates include a few other groups, such as the group that includes the lancelets 153 Amniotes Need to know 154
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Amniotes Includes Mammals and Reptiles In contrast with eggs in amphibians, the amniotic egg is relatively impermeable to water and allows the embryo to develop in a contained aquatic environment. Oxygen and carbon dioxide can pass across the egg shell, however. Skin tough and impermeable: scales, or modifications of scales, such as hair or feathers 155 Reptilia Includes Turtles, Crocodiles, Snakes, Lizards, a lizard-looking critter called a Tuatara .... and Birds (!) Diapsid skull, which includes two holes (fenestrae) behind the eye socket (modified in some lineages, such as turtles) 156 Squamates Snakes + lizards = Squamates 9000 species Synapomorphies include paired hemipenes, and details of the teeth and skull.
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  • Spring '18
  • MORRIS
  • Sarcopterygii

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