Phylum Chordata Subphylum Vertebrata Class Mammalia: US! Biology 11 Phylum Chordata Subphylum Vertebrata Class Mammalia: US!

Class Mammalia Mammalian Evolution: Also evolved from the reptiles in late Mesozoic Existed as small rodent-like animals that burrowed in the ground Were able to survive end of Mesozoic and were pre-adapted to the new cool dry reality Completed the vertebrate evolution to land Class Mammalia

Mammalia Objectives General characteristics 6 body systems: circulatory, respiratory, integumentary, reproductive, nervous, skeletal 3 subclasses and example animals Mammalia Objectives

Mammalian Characteristics 4 chambered heart Hair or fur Diaphragm for breathing Amniotic egg Mammary glands for nursing young Extensive post natal care Learning and reasoning levels of behavior Mammalian Characteristics

Class Mammalia Advances and Characteristics: 1. Circulatory System Complete four chamber heart and circulatory pattern (same as Aves except for the whole air sac business ) 2. Respiratory System Highly efficient lungs with muscular diaphragm Class Mammalia

Class Mammalia 3. Body Covering Covered with hair for insulation (modified scales) and sensing All mammals are endothermic Have a layer of subcutaneous fat for insulation and food storage Class Mammalia

Class Mammalia 4. Reproduction Internal fertilization & development Amniotic egg: modified to include placenta Nurse young with mammary glands Young born very immature - require extensive post natal care (18yrs worth! ) Class Mammalia

Class Mammalia 5. Nervous System Most advanced nervous system in the animal kingdom Great increase in cerebrum (convoluted) Very well developed senses Behavior reaches learning and reasoning levels – infant care, mating & societies Class Mammalia

Brain Regions and Functions Frontal Lobe thinking, planning, & central executive functions; motor execution. Parietal Lobe somatosensory perception, integration of visual & somatospatial information. Temporal Lobe language function and auditory perception involved in long term memory and emotion. Occipital Lobe visual perception and processing. Brain Regions and Functions

Class Mammalia 6. Skeletal Limbs are well adapted for land and water & allow very rapid movement Class Mammalia

Class Mammalia Classification 1. Subclass Prototheria (the monotremes) The mammals are placed into three Orders: 1. Subclass Prototheria (the monotremes) Have fur & nurse young Have a bird bill & lay eggs which they incubate outside body Today represented only by Duck Billed Platypus and the two species of Anteater An evolutionary dead end

Class Mammalia 2. Subclass Metatheria (the marsupials) Do not have a uterus (but do have a short lived placenta!) complete development in the pouch fused to mammary gland First major group of mammals to evolve – spread all over Earth – adaptive radiation Became reduced globally due to competition from placental mammals Class Mammalia

Class Mammalia Example Marsupials: The North American marsupial is the opossum – an omnivore The Australian marsupials are represented by kangaroos, wallabies, possums and koala bears among many others – all herbivores

Possum (Australian) Opossum (American)

Class Mammalia 3. Subclass Eutheria (the placental mammals) Complete internal development due to placenta – an organ of exchange between mother & fetus Most common order of mammals today - includes us! Dominant land vertebrate - adaptive radiation! Class Mammalia