Reptiles Which one is a reptile which one an amphibian?

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ReptilesWhich one is a reptile which one an amphibian?

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I. Reptiles

A. What is a Reptile

1. The basic body plan of a reptile is a well-developed skull, a backbone and tail, two limb girdles and for limbs.

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2. Two types of reptiles have slightly different body plans. Snakes are limbless and turtles have hard shells that are fused to their vertebral column.

 3. A reptile is a vertebrate that has dry, scaly skin, lungs and terrestrial eggs with several membranes.

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4. Reptile skin is dry and often covered with thick, protective scales. These scales may be smooth or rough.

 5. The body covering helps prevent the loss of body water in dry environments.

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6. The skin can also be a disadvantage to reptiles because the skin does not grow with the animal. It must shed its skin periodically.

 7. The only places on Earth that most reptiles cannot live in are very cold areas.

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B. Evolution of Reptiles

1. Reptiles evolved from amphibian like were the first vertebrates to develop the adaptation to lay eggs on land.

 2. The fossil record of reptiles date back to 350 million years ago.

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3. By the end of the Permian period, about 245 million years ago there was a mammal like reptiles these were the dinosaurs.

 4. At the end of the Cretaceous Period about 65 million years ago there was a mass extinction of the dinosaurs.

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5. The extinction was caused by a dramatic series of natural disasters.

 6. A bunch of massive volcanic eruptions and lava flows, dropping of sea level and a huge asteroid or comet smashing causing forest fires and dust clouds. These are a few of the theories.

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C. Form and Function

1. Most reptiles have adapted to a fully terrestrial life.

 2. Well developed lungs; a double-loop circulatory system a water conserving excretory system, strong limbs, internal fertilization, shelled, terrestrial eggs are the other adaptations that have contributed to the success of reptiles on land.

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D. Body Temperature Control

1. Ectoderms rely on behavior to help control body temperature.

 2. To warm up they will lie in the sun, to cool down they will go in the shade.

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E. Feeding

1. Reptiles eat a wide range of food.

 2. Iguanas are herbivores and tear plants in chunks.

 3. Many other reptiles are carnivores.

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F. Respiration

1. The lungs of reptiles are spongy providing for more gas-exchange.

 2. Reptiles CANNOT breathe through their skin.

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3. Several species of crocodiles have flaps of skin that can separate the mouth from the nasal passages, allowing these crocodiles to breathe through their nostrils while their mouth remains open.

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G. Circulation

1. Reptiles have a double loop circulatory system.

 2. One of the loops brings blood to and from the lungs and the other loop brings blood to and from the rest of the body.

 3. Most reptiles have a single ventricle with a partial septum to separate bad blood from good blood.

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H. Excretion

1. Urine is produced in the kidneys.

2. Reptiles’ urine contains either ammonia or uric acid.

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3. Reptiles that live in the water such as crocodiles and alligators have ammonia as liquid waste because they drink lots of water.

 4. Reptiles that are on land eliminate uric acid.

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I. Response

1 1. The basic pattern of a reptile’s brain is similar to that of an amphibian.

 2. Reptiles that area active during the day have cones in their eyes to see color.

 3. Many snakes have good sense of smell.

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4. Many reptiles have sensory organs in the roof of their mouth to detect chemicals.

 5. They have simple ears with an external eardrum.

 6. Snakes can also pick up vibrations in the ground through bones in their skulls.

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 7. Some snakes can even detect body heat.

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J. Movement

1. Compared to most amphibians, reptiles with legs tend to have larger, stronger limbs which allows them to walk, run, burrow, swim and climb.

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K. Reproduction

1. All reptiles reproduce by internal fertilization.

2. Most male reptiles have a penis like organ.

 3. Most reptiles are oviparous, laying eggs that develop OUTSIDE the mother’s body.

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4. Some reptiles leave the eggs unguarded some reptiles like alligators will provide some care after hatching.

 5. Some snakes and lizards are ovoviviparous and the young are born alive.

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6. Unlike an amphibian egg, the shell and membranes of a reptilian egg create a protected environment in which the embryo can develop without drying out.

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7. This type of egg is called an amniotic egg, named after the amnion, one of the four membranes that surrounds the developing embryo.

 8. The other three membranes are the yolk case, the chorion, and the allantois.

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9. The amnion is a fluid filled sac that surrounds and cushions the developing embryo. It produces a presoaked, watery environment.

 10. Chorion regulates the transport of oxygen from the surface of the egg to the embryo and transport of carbon dioxide.

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11. Yolk sac is a baglike structure contains a yolk that serves as a nutrient rich food supply for the embryo.

 12. Allantois stores the wastes produced by the embryo. It later fuses with the chorion and serves as a repository organ.

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L. Groups Of Reptiles

1. The four surviving groups of reptiles are lizards, snakes, crocodilians, turtles and tortoises and tuatara.

 2. Modern lizards and snakes belong to the order Squamata or scaly reptiles.

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Squamata

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3. Most lizards have legs, clawed toes, external ears and movable eyelids.

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4. Some lizards have evolved into highly specialized forms. Some live in trees and bushes, eating insects.

 5. The world’s largest lizard the monitors are the only reptiles alive today that provide some idea of what small dinosaurs may have been like.

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6. Many eat birds and mammals. The largest is the Komodo dragon with the length of 3 meters and the mass of 75kilograms.

 7. Komodo dragons can kill and eat their animals as large as a water buffalo.

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8. Snakes have lost both pairs of legs during the course of evolution.

 9. Snakes like sharks have a bad reputation. More people die from bee stings than from snakebites.

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10. Alligators, crocodiles, caimans and gavials all belong to the order Crocodilian.

 11. Crocodiles are carnivores, they are protective of their young.

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12. In 200 million years since then alligators a crocodiles have changed little.

 13. Crocodilians are the largest living reptiles. Some can live in fresh water or salty water

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Alligator

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Crocodile

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14. Turtles and tortoises are members of the order Testudines.

 15. Turtles and tortoises have a shell built into the skeleton.

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16. The shell consists of two parts: a dorsal part or carapace and a ventral part or plastron.

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17. Lack teeth but have jaws powerful enough to deliver a bite.

18. Turtles and tortoises members of the order Chelonia also evolved a successful way of life during the Triassic Period and have changed little over the last 200 million years.

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19. Turtle usually refers to members that live in water.

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 20. Tortoises are those that live on land

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21. Tuatara is the only surviving species of the order Sphenodonta. They look like lizards.

 22. They also have a “third eye,” This eye can sense the level of sunlight but its function is unknown.

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M. Ecology of Reptiles

1. Many reptiles are in danger because their habitats have been destroyed.

 2. Humans hunt reptiles for food, to

sell as pets and for their skins. 

3. Laws protect some species like the sea turtle.

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N. The evolution of Temperature control

1. Control of body temperature is important for animals, particularly in habitats where temperature varies widely with time of day and with seasons.

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  2. Ectotherms are animals that cannot maintain a constant body temperature. They get their heat from the environment sunbathing. Examples, turtles, snakes and other modern reptiles.

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3. Ectothermic animals are often incorrectly thought of as cold-blooded. Cold-blooded animals may have a body temperature higher than their surroundings.

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4. Animals that are endotherms are able to keep a constant body temperature. Birds and mammals are examples

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  5. Endothermic animals are often incorrectly thought as warm-blooded animals. Many times they have lower body temperatures than their environment.

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THE END