WILD 3580 1st Edition Lecture 35Outline of Last Lecture I. MigrationOutline of Current Lecture I. Characteristics of MammalsII. Mammalian Evolution III. Mammalian Classification Current LectureI. Characteristics of Mammals 1. Single bone in the lower jaw (dentary)a. Dentary-squamosal jaw articulation b. Quadrate-articular jaw articulation (non-mammal)2. Three middle ear ossicles a. Malleus- used to be the articular bone b. Incus- used to be the quadrate bone c. Stapes 3. Secondary Palate a. Separates the oral cavity from the nasal cavity b. Facilitate efficient respiration (through nose than just mouth) for nursing 4. Hair a. Insulation 5. Mammary glandsa. Provide nourishment to the young 6. Enucleate erythrocytes a. Red blood cells lack a nucleus b. Carry more oxygen- more surface areaII. Mammalian Evolution - Mid to late Triassic period of Mesozoic Era - Synapsid group: single temporal opening - Amniota diverged to reptiles and mammals - Mesozoic Mammalso Rare in most areas of the world These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Smallo Nocturnal - Dinosaurs dominated most terrestrial niches i. Smaller mammals evolved hair as a form of insulation ii. Active during night - Mammals start really diversifying throughout the Cenozoic Era - Almost exponential growth a. 2 major worldwide events1. Extinction of dinosaurs 2. Breakup of Pangea - Isolation local adaptation divergence speciation III. Mammalian Classification a. Class Mammalia- 5416 species b. Subclass Prototheria- monotremes (Platypus)i. 1 order, 2 families, 3 species c. Subclass Theriai. 2 infraclasses 1. Metatheria- marsupialsa. 7 orders 2. Eutheriaa. 21
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