Interest Grabber Out on Dry Land Think about animals that live in the water and the features they share. When animals moved onto dry land, decreased availability of water presented new problems for them. Think about the challenges posed by the “move onto dry land.” Section 31-1 With a partner, describe how each of the following characteristics exhibited by reptiles allows for life on land and how these characteristics differ from those of water-dwelling animals. 1. Dry, scaly skin 2. Lungs 3. Shelled eggs

Section Outline 31–1Reptiles A.What Is a Reptile? B.Evolution of Reptiles 1.Mammal-like Reptiles 2.Enter the Dinosaurs 3.Exit the Dinosaurs C.Form and Function in Reptiles 1.Body Temperature Control 2.Feeding 3.Respiration 4.Circulation 5.Excretion 6.Response 7.Movement 8.Reproduction Section 31-1

Section Outline continued D.Groups of Reptiles 1.Lizards and Snakes 2.Crocodilians 3.Turtles and Tortoises 4.Tuataras E.Ecology of Reptiles Section 31-1

To body To lungs From body From lungs Right atrium Left atrium Incomplete division Ventricle Kidney Liver Heart Lung Digestive tract Bladder Cloaca The Structure of a Turtle’s Heart

Section 31-1 Allantois Embryo Shell Amnion Chorion Yolk sac Figure 31–8 The Amniotic Egg The chorion regulates the transport of oxygen from the surface of the egg to the embryo and the transport of carbon dioxide, one product of respiration, in the opposite direction. This baglike structure contains a yolk that serves as a nutrient-rich food supply for the embryo. The amnion is a fluid-filled sac that surrounds and cushions the developing embryo. It produces a protected, watery environment. The allantois stores the waste produced by the embryo. It also serves as a respiratory organ.

Interest Grabber Silent Spring Rachel Carson wrote the book Silent Spring in the 1960s. As the title suggests, she describes waking up on a spring morning, hearing none of the usual chirping of songbirds and wondering what happened to them. Carson’s book increased awareness of the use of pesticides in the environment. Unfortunately, one of the chemicals that had been used interfered with the formation of the shells of birds’ eggs. Section 31-2 With a partner, discuss and answer the questions that follow. 1. What effect would weak eggshells have on the population of birds? How might this cause a “silent spring”? 2. If you were a legislator, what would you do about the use of chemicals such as pesticides in our environment?

Section Outline 31–2Birds A.What Is a Bird? B.Evolution of Birds C.Form and Function in Birds 1.Body Temperature Control 2.Feeding 3.Respiration 4.Circulation 5.Excretion 6.Response 7.Movement 8.Reproduction D.Groups of Birds E.Ecology of Birds Section 31-2

which arethat alsothat powerthat providethat ensure have the following adaptations to flight Concept Map Birds Homologous to front limbs in other vertebrates Provide warmth Upward and downward wing strokes One-way flow of O 2 -rich air O 2 distribution to body tissues WingsFeathers Strong chest muscles Efficient respiratory system Efficient circulatory system

Section 31-2 Esophagus Crop Liver First chamber of stomach Gizzard Small intestine Cloaca Pancreas Air sac Kidney Heart Lung Brain When a bird eats, food moves down the esophagus and is stored in the crop. 1 As digestion continues, the food moves through the intestines. 4 Undigested food is excreted through the cloaca. 5 Large intestine The muscular walls of the gizzard squeeze the contents, while small stones grind the food. 3 Moistened food passes to the stomach, a two-part chamber. The first chamber secretes acid and enzymes. The partially digested food moves to the second chamber, the gizzard. Figure 31–14 The Anatomy of a Pigeon 2

Section 31-2 Right atrium Left atrium Complete division Heart Domestic pigeon Left ventricle Right ventricle Figure 31–16 The Structure of a Bird’s Heart