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Chapter 30MAMMALS
MAMMALS• Existed for 200 million years
• Therapsids - features of both reptiles & mammals
All mammals have: 1. Hair 2. Mammary glands
Hair: ~Keratin
CLASS MAMMALIA• Hair:
~Insulation ~Waterproofing ~Conserve heat
CLASS MAMMALIA
• Mammary glands - secrete milk
CLASS MAMMALIA
• 4-Chambered Heart• Endotherms• Cooling
– Panting or sweat glands
CLASS MAMMALIA
• Modified limbs 1. Opposable thumbs 2. Various joint types
CLASS MAMMALIA
• Diaphragm• Well-defined teeth 1. Incisors - biting 2. Canines - tearing
flesh 3. Molars - chewing
Primates - most intelligent group of animals: - Complex behaviors:- Learning and remembering- Highly developed brains
•Parental care - Guard young and teach them
Three types of mammals:
1. Monotremes 2. Marsupials3. Placental Mammals
MONOTREMES• Reproduce by laying eggs
• Only in Australia, Tasmania, New Guinea
• 3 species alive today– Spiny anteaters (echidnas) – 2 species– Duck-billed platypus
MARSUPIALS• Marsupial - short period of development in
uterus, second period inside a pouch
• Mostly in Australia
• One U.S. species
PLACENTAL MAMMALS• Female carries its young inside the uterus until
almost completely developed
• Gestation - time spent in uterus
VAGINA
Uterus - hollow, muscular organPlacenta - O2, nutrition, wastes
COWDIGESTIONCud Chewing -
breaking down plant materials (cellulose)
Only in
India!