1. Chapter 30 – Class: MAMMALIA I. Characteristics of Mammals
A. Hair – made of keratin protein; evolved from scales
1. Hair is used for:
Insulation – conserves body heat
Camouflage
Waterproofing
Defense
Sense changes in environment

2. 2. Cooling Off
 Panting: releases water from nose & mouth, causing loss of body heat
 Sweat glands: moisture is secreted onto skin’s surface; as moisture evaporates, heat from body is transferred to air
B. Mammary Glands produce & secrete milk that is rich in nutrients

3. C. Diaphragm – sheet. of muscle that. expands chest
C. Diaphragm – sheet of muscle that expands chest cavity to get O2 into lungs
D. 4-chambered heart – fully separates O2-rich blood from O2-poor blood, delivering the maximum amount of O2 to the body

4. E. Special Teeth – based on diet
1. Incisors – chiseled flat for biting & cutting
2. Canines – sharp for stabbing & tearing
3. Premolars & Molars – flat for grinding & crushing

5. F. Endothermic
G. Internal Fertilization
H. 2 pairs of limbs in most species – for food gathering (opposable thumbs, wings, etc.)

6. I. Highly developed brains - mammals:
1. can learn
2. use tools
3. are the most intelligent animals

7. II. Diversity of Mammals – 3 Subclasses, based
II. Diversity of Mammals – 3 Subclasses, based on method of reproduction
A. Monotremes
1. Lay amniotic eggs
2. platypus, spiny anteater/echidna
3. Found only in Australia, Tasmania, & New Guinea – evolved after Pangaea split up

8. B. Marsupials
1. Young develop incomplete inside mother, then in pouch made of skin & hair – are blind & hairless
2. koala, kangaroo, opossum
3. Found mainly in Australia – evolved before Gondwana split up

9. C. Placental Mammals (90% of all mammals)
1. Young develop inside mother’s muscular uterus until body systems are fully functional & can live independently of mother’s body
2. Placenta – organ that provides nutrients to offspring
3. Gestation varies by body size, but these mammals are better protected 4. Human, dog, horse, lion, seal, whale
5. Found Worldwide – evolved before Pangaea split up

10. III. Orders of the class MAMMALIA
Order INSECTIVORA – shrew, mole
Order CHIROPTERA – bat
Order RODENTIA – rat, squirrel, gopher
Order LAGOMORPHA – rabbit, hare
Order EDENTATA – armadillo, sloth,
giant anteater
Order CETACEA – whale, dolphin
Order SIRENIA – manatee
Order PROBOSCIDEA – elephant
Order CARNIVORA – dog, cat, lion, bear, seal, walrus
Order ARTIODACTYL – cow, deer (even #)
Order PERISSODACTYL – horse (odd #)
Order PRIMATES – gorilla, monkey, man