Zoology 10th Edition by Stephen Miller,John Harley

تمرين 12

Mammals are characterized by hair, mammary glands, specialized teeth, three middle-ear ossicles, and endothermy. The evolution of mammals was strongly influenced by continental movements that separated a single landmass, Pangaea, first into southern and northern supercontinents and later into the continents of North America, Europe, and Asia. These and other movements isolated groups of mammals, resulting in four clades. Placental mammals are further divided into 18 orders.
How are biogeographic events important influences on mammalian evolution?
FIGURE 22.5 Order Xenarthra. ( a ) A giant anteater ( Myrmecophaga tridactyla ). Anteaters lack teeth. They use powerful forelimbs to tear into an insect nest and a long tongue covered with sticky saliva to capture prey. ( b ) An armadillo ( Dasypus novemcinctus ).