Ch. 34 - Reptiles

Ch. 41 - ReptilesUnlike amphibians, reptiles dont have to return to the water to reproduce. They were the first vertebrates to live on land during their whole life cycle.Reptiles evolved a new reproductive structure that allowed them to reproduce on land. What is this structure?Amniote eggVideoAmniote Egg ( 5 parts)1. Porous shell protects & prevents water loss.2. Amnion salty fluid that allows the embryo to float.3. Allantois excretes nitrogenous waste from the embryo4. Chorion lines the outer shell. Diffuses carbon dioxide & oxygen through the shell.5. Yolk sac supplies food for the embryo.

Characteristics of Reptiles1. Dry body covering (some with scales)Made of keratin to prevent water loss.2. Lungs3. 3-chambered heart with the ventricle partially divided. (alligators have 4)4. Ectotherms body temperature is influenced by the environment.5. Limbs, if present, have toes with claws.6. Internal Fertilization (big advantage)VideoOrigin of ReptilesReptiles were thought to of arose from the cotylosaurs. Pg. 841Mesozoic era is known as the Age of Reptiles.When were the dinosaurs thought to have become extinct?Cretaceous PeriodDinosaur means terrible lizard

Reptile Orders Cl.: Reptilia1. RhynochocephaliaTuatara the only species in this orderOnly in New ZealandParietal eye 3rd eye on the top of their head

2. Chelonia TurtlesDorsal shell is called the carapaceVentral shell is called the plastronA bridge connects the two.Turtles are protected very well with their shell.Snapping turtles are one of the more aggressive turtles. They have a worm-like tongue to attract fish.Video

3. CrocodiliaCrocodiles & alligatorsCaimans (short & wide snout) & gavials (long & narrow snout).The only living relatives of the dinosaurs.Have you ever wondered why an alligator or crocodile doesnt swallow a lot of water when it has its mouth open?It has a glottis that prevents this.Have you ever heard of the Crocodile Man?Video

4. Squamata Largest OrderLizards & SnakesThere are only 2 poisonous lizards 1. Gila Monster S.W. U.S. Has grooved teeth with venom & shakes its head to release the venom.2. Beaded Lizard Western MexicoName as many lizards a possibleIguanas, horned toads, chameleons, skinks, & geckosVideo

Horned lizards or horny toads live around here. They have armored spikes covering them and when disturbed they hiss and squirt blood out their eyelids.Skinks and geckos have the ability to lose their tails and regenerate a new one.The term for this is autotomy.Video

SnakesNo limbs and no external earsThere is evidence for believing that snakes once had legs. Some pythons & boas still have vestigial hind legs.How many of you fear snakes?How many of you fear rattlesnakes?A graduate study was done on the human perception of snakes.Video

2,800 species of snakes, only 300 species are poisonous or dangerous.What are the poisonous snakes of Kansas?Prairie rattlesnake, pigmy rattlesnake, cottonmouth, western diamondback rattlesnake, timber rattlesnake, copperhead.VideoWhat is the largest snake in the world?Anaconda (33 ft.), smallest is about 4 in.What does molting mean?Snakes have between 100 400 vertebrae

3 ways of movement in snakes1. Lateral Undulation most common method for crawling or swimming.Draw2. Rectilinear or caterpillar movement is the contract and condense of the muscles.Draw3. Sidewinding mostly used by???Draw

Snake PartsNictitating membrane to cover their eyes.Forked tongue that is used for the great sense of smell.The branches of their tongue pick up particles in the air, then slide over top their Jacobsons organs at the roof of their mouth, which are sensitive to odors.All snakes are carnivoresA snakes jaw can unhinge to engulf their prey.Video

What are the 2 methods snakes use to kill its prey?3 methods of injecting venom:1. Vipers large front fangs (hypodermic)Ex. Rattlesnake, copperheads, cottonmouth2. Elapids small front fangs (hypodermic)Ex. Cobra & coral snakes

3. Rear-fanged snakes bite the prey & use grooved back teeth to inject the venom.Twig snakes & boom slang snakes of Africa

2 types of poisons in venom1. Neurotoxins affects the nervous systemCant breath or swallow2. Hemotoxins affects the circulatory systemDestroys the blood vessels (rupture)Some snakes use pits to detect heat from warm-blooded mammals. (pg. 836)Name the snake that can eat a rattlesnake?King snake

ReproductionInternal FertilizationOviparous lays the eggs outside her body.Ovoviviparous eggs are hatched inside her body. Not nourishedViviparous bear live young that are nourished inside her body until they are developed.A snake breaks through the shell by using an egg tooth, which is lost after it breaks through the egg.