Interest Grabber

1. Interest Grabber Section 32-1 • A Warm Body • Because mammals and birds generate heat within their bodies, they are endotherms. Other types of chordates control body temperature by behavior. These animals are ectotherms. 1. Mammals and birds eat much more food than do other types of chordates. Why do you think this is necessary? 2. What body features do endotherms have that would provide insulation to conserve heat produced within the body? Would you expect ectotherms to have such features? 3. What are two examples of endotherms? What is the specific type of insulation that each one has?

2. Section Outline Section 32-1 • 32–1 Introduction to the Mammals A. Evolution of Mammals B. Form and Function in Mammals 1. Body Temperature Control 2. Feeding 3. Respiration 4. Circulation 5. Excretion 6. Response 7. Movement 8. Reproduction

3. The Structure of a Bear’s Heart Section 32-1 Left atrium Right atrium Left ventricle Right ventricle Complete division

4. Figure 32–4 The Jaws and Teeth of Mammals Canines are pointed teeth. Carnivores use them for piercing, gripping, and tearing. In herbivores, they are reduced or absent. Chisel-like incisors are used for cutting, gnawing, and grooming. Molars crush and grind food. The ridged shape of the wolf’s molars and premolars allows them to interlock during chewing, like the blades of scissors. The broad, flattened molars and premolars of horses are adapted for grinding tough plants. Section 32-1 CARNIVORE HERBIVORE Jawjoint Jaw joint Horse Wolf

5. Interest Grabber Section 32-2 • Marsupials Versus Placentals • Kangaroos and humans are both mammals because of the characteristics they share. Still, they display enough different characteristics to result in a kangaroo being classified as a marsupial and a human being classified as a placental mammal. Consider what you know about kangaroos and humans, and then answer the questions that follow. 1. How do the young of kangaroos develop,and how do the adults care for their young? 2. How do humans and kangaroos differ from one another in caring for their young? 3. What characteristic do humans and kangaroos have in common in terms of caring for their young?

6. Section Outline Section 32-2 • 32–2 Diversity of Mammals A. Monotremes and Marsupials 1. Monotremes 2. Marsupials B. Placental Mammals C. Biogeography of Mammals

7. Compare/Contrast Table Section 32-2 Orders of Placental Mammals Examples Order Insectivores Sirenians Cetaceans Chiropterans Rodents Characteristics Long, narrow snouts, sharp claws Water-dwelling, slow-moving Live and breed in ocean, come to surface to breathe Winged, capable of true flight Single pair of long, curved incisor teeth in upper and lower jaws Shrews, hedgehogs, moles Manatees, dugongs Whales, dolphins Bats Mice, rats, voles, squirrels, beavers, porcupines, chinchillas

8. Compare/Contrast Table continued Section 32-2 Orders of Placental Mammals Order Perissodactyls Carnivores Artiodactyls Proboscideans Characteristics Examples Hoofed, with an odd number of toes on each foot Sharp teeth and claws Hoofed, with an even number of toes on each foot Trunks Horses, tapirs, rhinoceroses, zebras Tigers, hyenas, dogs, foxes, bears, raccoons, walruses Cattle, sheep, goats, pigs, ibex, giraffes, hippopotami, camels Asian and African elephants, mastodons and mammoths

9. Compare/Contrast Table continued Section 32-2 Orders of Placental Mammals Order Lagomorphs Xenarthrans Primates Characteristics Examples Two pairs of incisors in upper jaw, hind legs allow leaping No teeth (or very small teeth in the back of the jaw) Highly developed cerebrum and complex behaviors Snowshoe hares, rabbits Sloths, anteaters, armadillos Lemurs, tarsiers, apes, gibbons, macaques, humans

10. Figure 32–13 Convergent Evolution of Insect-Eating Mammals Section 32-2 ChinesePangolin Nine-BandedArmadillo CommonEchidna Giant Anteater Aardvark

11. Interest Grabber Section 32-3 • Skeletal Features of Primates • Recall that primates are an order of mammals. One difference that exists between primates and other mammals is in the structure of the primate skeleton. Some examples of primates include humans, lemurs, monkeys, and apes. 1. How are the external features of your hands different from the external features of the paws of a dog or the hooves of a horse? 2. Primates are bipedal, or capable of walking on two limbs. What is an advantage of being bipedal? 3. What are some characteristics of your skeleton that enable you to stand and walk?

12. Section Outline Section 32-3 • 32–3 Primates and Human Origins A. What Is a Primate? 1. Fingers, Toes, and Shoulders 2. Well-Developed Cerebrum 3. Binocular Vision B. Evolution of Primates 1. Prosimians 2. Anthropoids

13. Section Outline continued Section 32-3 C. What Is a Hominid? 1. Early Hominids 2. Australopithecus 3. Paranthropus 4. Kenyanthropus 5. How Do the Branches Connect? D. The Road to Modern Humans 1. The Genus Homo E. Out of Africa—But Who and When? F. Modern Homo sapiens

14. Comparison of Skulls of Human Ancestors Section 32-3 Large brow ridge Large nose Large canine teeth Face protrudes forward Australopithecus afarensis Homo erectus Round, high skull Weak brow ridge Large brain case Inflated cheeks Largenose Even teeth Strong chin Neanderthal Cro-Magnon Modern Homo sapiens

15. Figure 32–16 Human and Gorilla Skeletons Section 32-3 Comparing Human and Gorilla Skeletons Modern Human Modern Human Modern Gorilla Modern Gorilla Skull atopC-shaped spine Spinal cord exitsnear back of skull Arms longer thanlegs; hands touch ground during walking Pelvis is longand narrow Thigh bones angledaway from pelvis Skull atopS-shaped spine Spinal cord exitsat bottom of skull Arms shorter thanlegs; hands do not touch groundduring walking Pelvis is bowl-shaped Thigh bones angledinward, directlybelow body