Amphibians and Reptiles

Amphibians and Reptiles Test #3

First vertebrates on land were in Class Amphibia Amphibian-means “two lives” About 4,000 species of frogs, salamanders, and caecilians (limbless animals that burrow in tropical forests and fresh water lakes) Class: Amphibia

Devonian Time Period • Cycles of drought and then heavy rainfall then drought again • Lobe-finned fish were at an advantage because the bones in their fins are like that in the arms and legs of early amphibians • They were able to come to land to escape predators or to get food.

3 Orders of Amphibians • 1. Urodela • “tailed ones” • salamanders • 2. Anura • “tail-less ones” • frogs & toads • 3. Apoda • “leg-less ones” • caecilians

400 species Some are entirely aquatic and some live on land Most walk by bending their body from side to side Order: Urodela (Salamanders)

Order: Anura (Frogs and Toads) • 3,500 species • More specialized for living on land • Use strong legs to hop • Flick tongue to catch insect

Frogs are in the family Ranidae and have the following characteristics: Bulging eyes Webbed feet and longer legs for swimming Smooth or slimy skin Lay eggs in clusters What is the difference between frogs and toads?

Toads are in the family Bufonidae and have the following characteristics: Stubby bodies with short hind legs for walking instead of hopping Warty dry skin Poison glands behind the eyes Lay eggs in chains Toads

Camouflage Secrete mucous that is bad tasting or poisonous Many with poison have a bright color to warn predators Defense from predators

Legless Nearly blind Look like earthworms Order: Apoda (Caecilians)

Amphibian Characteristics • Frogs • Tadpole --------------------------Adult • Aquatic with gills Gills & tail disappear • Lateral line Lateral line • Finned tail Develops legs

Frogs • Frogs have air breathing lungs, eardrums, and a digestive system (carnivorous diet) • Some frogs do not go through the tadpole phase • Some are strictly aquatic and some are strictly land • Salamanders and caecilians resemble adults when born • Even land-dwelling amphibians need a moist habitat • Some breathe through skin and mouth b/c they have no lungs

Frogs • Eggs do not have a shell and dehydrate in air • Male causes female to release eggs and spills sperm while she does this • Some incubate eggs on back, mouth, or in stomach • Some are ovivaporons (eggs hatch in uterus) and viviparons (young develop in uterus) • Social life • Frogs are usually quiet, but many call during mating season • Many want to protect territory or attract females

Class: Reptilia • 7,000 species • Many extinct species • Mainly lizards, snakes, turtles, and crocodilians • Birds are closely related

Reptile Characteristics • Scales create waterproof skin • (Helps prevent dehydration in air) • Have lungs because they can’t breathe through moist skin • Some turtles have gas exchange through their moist cloaca • Most lay shelled eggs on land • Internal fertilization

Reptile Characteristics • Called “cold-blooded” or ectothermic because they don’t use their metabolism to control their body temperature • they regulate their temperature in other ways • Ectotherms body temperature changes with their surroundings

Extinct Reptiles • 1. Dinosaurs2. Pterosaurs • lived on land flying reptiles • different sizes wings were a membrane • up to 45 m long of skin stretched from the body wall to the tip of an elongated finger • many were very fast • social and give parental care

Modern Reptiles • 3 Largest Orders • 1. Chelonia (turtles) • 2. Squamata (lizards and snakes) • 3. Crocodilia (crocodiles and alligators)

Have not changed much since the Mesozoic era What is the difference between a turtle and a tortoise? Turtles are any reptile that lives in a shell. A tortoise is a turtle that lives on land but enters the water for various reasons. Order: Chelonia

Lizards- most numerous and diverse May have survived cold by nesting in crevices to maintain heat Order: Squamata

Snakes- descendants of lizards that adopted a burrowing lifestyle Today, most snakes live above ground Boa’s have vestigial pelvic and limb bones (primitive snakes) Snakes are carnivorous They have chemical sensors on their tongue that helps them detect prey have no ear drums feel vibrations on the ground they have heat detecting organs between the eyes and nostrils they inject poison through hollow teeth They have loose jaws that help swallow prey Order: Squamata

Largest living reptiles Spend most of their time in water breathing through upturned nostrils Live in warmer areas Most closely related to dinosaurs of all the reptiles Birds are the closest relatives to reptiles Crocodilians (crocodiles and alligators)

Crocodile: Has a long V shaped snout Upper and lower jaws are the same width so teeth show interlocking when mouth is shut What is the difference between a crocodile and an alligator?

Alligator: Wide U shaped snout Have a wider upper jaw so that the teeth from the upper portion only show when the mouth is closed. What is the difference between a crocodile and an alligator?

Amphibians and Reptiles