Reading Essentials for Biology Glencoe (794133), страница 85
Текст из файла (страница 85)
Amphibians probably arose as theydeveloped the ability to breathe air through well-developed lungs.The ability to live on land depended on adaptations, or changes,that would provide support for the body, protect the membranesinvolved in respiration, and provide for efficient circulation.5. Name two advantagesand two disadvantages ofliving on land.________________________________________________________________________________________________374Chapter 30What were the benefits and challenges ofliving on land?There were many benefits to living on land.
There was a largefood supply and good shelter. At the time, there were no predators. There was more oxygen on land than in the water. However,life on land was dangerous. Air temperature varied. When thebody was out of the water, it was heavy and clumsy. Movementwas more difficult.Amphibians first appeared about 360 million years ago. Theyprobably evolved from an aquatic tetrapod around the middle ofthe Paleozoic Era. The climate on Earth was warm and wet.Because these early amphibians could breathe through theirlungs, gills, or skin, they became the dominant vertebrates onthe land.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.4.
Analyze What characteristics do caecilians havethat make them adaptedfor life as burrowers?How are caecilians different than otheramphibians?NameDateClassSection30.2Amphibians, continued◗ After You ReadMini Glossaryectotherm (EK tuh thurm): an animal whosebody temperature changes; an ectothermgets its heat from external sourcesvocal cord: band of tissue located in the throat;as air passes over the cord, it vibrates, andthe molecules around the vocal cord tissuesvibrate, making sounds1.
Read the terms and their definitions in the Mini Glossary above. Use the space below towrite a brief paragraph explaining how these two terms relate to the life cycle of a frog.____________________________________________________________________________________________________________________________________________________________2. Use the diagram below to show list the facts you have learned about the three orders ofAmphibia.
In the box labeled Amphibians list characteristics common to all amphibians.Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.AnuraAmphibiansCaudataApoda3. How are caecilians different from other amphibians? Write your response on the line below.____________________________________________________________________________________Visit the Glencoe Science Web site at science.glencoe.comto find your biology book and learn more about amphibians.READING ESSENTIALSChapter 30375NameDateClassSection31.1 ReptilesSC.F.1.4.2 The student knows that body structures are uniquely designed and adapted for their function. SC.G.1.4.1The student knows of the great diversity and interdependence of living things.
Also covers SC.F.1.4.7◗ Before You ReadOften lizards and snakes appear to be lazily enjoying a sunny day. At the same time, they may bewatching for both prey and predators. Why do snakes and lizards stay in the warm sun if it meansexposing themselves to danger? On the lines below, explain why you think lizards and snakesbehave this way. After you read this section, check your explanation and update it to reflect whatyou have learned.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnWhat is a reptile?How does scaly skin protect reptiles?Reptiles have a dry, thick skin.
The skin is covered with scales.The scales are made of protein and are part of the skin itself. Scalesprevent the loss of moisture from the body and provide protectionfrom predators. Gas exchange cannot occur through scaly skin.The lungs are the primary organs for gas exchange in reptiles.How do reptiles reproduce?Most reptiles reproduce by laying eggs on dry land. Somesnakes give live birth to well-developed young. All reptiles haveinternal fertilization.
Usually, eggs are laid after fertilizationoccurs. Reptile eggs are amniotic (am nee AH tihk). An amnioticegg provides nourishment, or food, for the embryo. An embryois the earliest stage of growth and development of both plantsand animals. The amniotic egg, shown in the figure on page 377,contains membranes that protect the embryo while it develops onland. An amniotic egg serves as the embryo’s total life-supportsystem. The evolution of the amniotic egg was the adaptation thatenabled reptiles to reproduce on land rather than in water.376Chapter 31READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.CreateDiagrams Draw two diagrams, one of a snake andone of a turtle.
As you readthis section, highlight theinformation that tells aboutthe similarities and the differences between these two.Label your diagrams and writeyour comparison.Snakes, turtles, alligators, and lizards belong to the class Reptilia.Early reptiles, called stem reptiles, were the first animals thatadapted to life on land. Unlike the amphibians, reptiles can complete all their life cycles on land.
They do not need a watery environment to reproduce.NameDateClassSection31.1Reptiles, continuedAmnionChorionShellEmbryoYolkAllantoisCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.AlbumenThe embryos develop after the eggs are laid. Most reptileslay their eggs under rocks, tree bark, or grass. Some reptiles digholes or prepare a nest for the eggs.
Most reptiles provide nocare for the young, but female crocodiles may guard their nestsfrom predators.How have body changes helped reptiles?The legs of amphibians are set at right angles to the body. Thelegs of early reptiles were placed more directly under the body.This under-the-body positioning provided better body support. Italso made running and walking easier. Because reptiles with legscould run and walk, they could catch their prey more easily. Theycould also better avoid their predators. Reptiles with legs alsohave claws. Sharp claws help them catch food and protect themselves. Other evolutionary changes in the jaws and teeth of earlyreptiles helped them to use other resources found on land.READING ESSENTIALSChapter 31377NameDateClassSection31.1Reptiles, continuedWhat kind of hearts do reptiles have?1.
What kind of heart doesan alligator have?________________________________________________________________________Most reptiles, like amphibians, have three-chambered hearts.Some reptiles, including crocodiles and alligators, have fourchambered hearts. A four-chambered heart completely separatesthe supply of blood with oxygen from the blood that does nothave oxygen. This separation allows more oxygen to reach bodytissues. Land animals require more energy than aquatic animals.Delivering more oxygen to body tissues was an important adaptation that enabled reptiles to live on land.Are reptiles ectotherms?How do reptiles obtain their food?2.
Analyze Why are mostturtles and tortoisesherbivores?________________________________________________________________________378Chapter 31Some reptiles are herbivores, and some reptiles are carnivores.All reptiles, however, have adaptations that make it possible forthem to find food. Most turtles and tortoises are too slow to beeffective predators. Most of these species are herbivores, but theturtles and tortoises that are predators eat worms and mollusks.Snapping turtles are aggressive predators. They attack fish andamphibians and will even pull ducklings under the water.Lizards mainly eat insects but some species of lizards are herbivores. The marine iguana of the Galápagos Islands eats marinealgae.
The largest lizard, the Komodo dragon, lives on severalislands in Indonesia. The Komodo dragon is a strong predator andwill attack humans. Although lizards, especially the large ones,may look slow or clumsy, they are able to run for short periods oftime. They use this ability to catch their prey.Snakes are also effective predators. Some species, including rattlesnakes, have poison fangs that they use to subdue or kill theirprey. A constrictor wraps its body around its prey to prevent theprey from breathing.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Reptiles are ectotherms.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
