The mammals

The mammals - The Mammals Mammalia from the word mamma that...

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Unformatted text preview: The Mammals Mammalia from the word mamma that means breast. o Highly developed nervous system and adaptations that allow them to live everywhere. o Not very large class About 4,000 species Diversity o Mammalian Size Diversity Kittis Hog-nosed bat 1.5 grams smallest mammal Blue Whale Largest animal to live on this earth 170 tons 30 meters in length o Humans play a large role in animals Domestication as pets and workers Use for coats and other types of clothing Taken for food Over cropping of whaling and fishing Used as beasts of burden Carrying packs, farming, etc. Used for biomedical research Exotic mammals Humans moved many animals to different locations Europeans moved rabbits to Australia, and they multiplied like crazy and ate all the vegetation. Human overpopulation Causing the habitat lost for animals Over 300 species of mammals are considered endangered by the International Union for the Conversation of Nature and Natural Resources o Includes primates, whales, dolphins, and wild cats We are the most highly evolved in the environment so we are responsible for everything else that happens Mammalian origins o Subclass Synapsida Order therapsida Commonly called the therapsids Speculation that some of them may have been warm-blooded Early Mesozoic during Triassic period group of reptiles with mammal characteristics Reptile legs had to move inward Move with more speed and efficiency for hunting and fleeing Nervous system undergoes more evolution Cerebellum evolves for movement and muscular coordination Separation of air and food passages in the mouth Allowed them to breathe air while they are feeding or carrying prey in their mouth Hard pallet separates nasal a buccual passages Stronger jaws Allowed for prolonged chewing and predigestion of food Late in Triassic period got distinctive mammalian characteristics Hair and mammary glands Class Mammalia o Subclass Theria only subclass under this class Infraclass Ornithodelphia Order monotraumata Monotremes egg laying mammals Spiny anteater, echidna, and platypus Infraclass Metatheria Order marsupialia Pouched animals o Opossum, kangaroo, wallabies Infraclass Eutheria Placental mammals Baby attached to the mothers body via organ placenta o Attached the developing embryo to the mother through the uteral wall that allows the embryo to receive food and release waste About 19 orders of Eutherians Descended from an ancestor that was around during the Jurassic Period (about 150 mya) Order Monotremata o Has many reptile features Mammal History o Not many fossils for the first mammals because they were really small after the extinction of dinosaurs they began to expand and develop....
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This note was uploaded on 09/19/2011 for the course 1 101 taught by Professor Larrydavid during the Spring '11 term at South Carolina.

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The mammals - The Mammals Mammalia from the word mamma that...

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