Biology 3484A/B Lecture Notes - Cetacea, Marsupial, Echidna
24 Dec 2012
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Document Summary
Class mammalia (mammals) synapomorphies: have hair growing from follicles in the skin. Have three middle ear bones used in hearing, allowing exceptional hearing ability. Have a neocortex region in the brain, allowing enhanced cognitive skills, memory, thinking, and language in primates. Females have mammary glands, which produce milk to feed to offspring. Mammal main groups: monotremes modern day representatives of early mammals. Marsupials short-lived placenta (specialized organ to nourish embryo). Modern monotremes are a surviving species of an early branching of the mammal tree. Includes echidna and platypus, which are indigenous to australia and new guinea. Marsupial mammals are found in australia, new guinea, north america, and south america. North american opossum is the only marsupial mammal found north of mexico. It is fairly common in the us, but is now found in london, on. It has been forced to expand its range due to habitat disturbance from humans.
