Zoology Amphibians & Reptiles

What does the name "amphibian" mean?

double life; referring to the transition from water to land.

Snake Movements- Rectilinear Movements

A muscular force is applied to the belly so scutes or scales on the belly catch on rough surfaces allowing the snake to moves forward slowly. -AKA "caterpillar movement"- slow, straight movement. -common for large snakes, such as large vipers, boas, and pythons. -use the wide ventral scales on their belly to grip the ground, while pushing forward with other scales.)

How do crocodiles and alligators catch their prey?

ALL are aggressive predators -Usually capture prey by floating just beneath the surface of water near shore and exploding out of water when an animal comes to drink. When they seize the prey they bring them back into the water to drown and eat them.

How many lizard species are still alive?

About 3,000 species- half the worlds reptile species are lizards.

When and how did the first amphibians evolve?

About 360 million years ago from lobe-finned fish.

Difference between temperature regulation between living on land vs water

Air fluctuates in temperature for readily than does water, and terrestrial environments harsh and unpredictable cycles of freezing, thawing, drying, and flooding. Terrestrial animals require behavioral and physiology strategies to protect themselves from thermal extremes.

Difference between density between living on land vs water

Air is less dense than water and provides less support against gravity. Terrestrial animals had to develop strong limbs and remodel their skeleton to achieve adequate structural support.

What were the first reptiles called?

stem reptiles

Herpetology

study of reptiles and amphibians

When did reptiles evolve from amphibians?

the Carboniferous Period

What is the dorsal and ventral surface of a turtles shell called?

Dorsal- carapace Ventral- plastron -(both joints are joined by a bony bridge)

Turtles brain

Very small- 1% of body weight. The cerebrum is larger than that of an amphibian, and turtles are able to learn a maze about as quickly as a rat.

Tennessee's Venomous Snakes

Western Cottonmouth, Timber Rattle Snake, Northern Copperhead, Pygmy Rattlesnake -How to tell if a snake is venomous in TN: check out the pupils. If they are round, the snake is nonvenomous. All TN venomous snakes have elliptical (cat-like) pupils.

Order Anura (salientia)

-Largest order with 44 families, 362 genera, and 5,283 species. -Anura means "without tail" since they lose their tail as they metamorphose into adults. -Salientia means "leaping"; frogs and toads are specialized for jumping. -Body: Head and trunk fused, no scales, two pairs of limbs, 6 to 10 vertebrae including urostyle (coccyx).

Why are amphibians called "pioneers of living on land?"

They were the first vertebrates to live on land.

Caecilians- Order Apoda (Gymnophiona)

-173 species; Means "without foot" -Elongate, limbless, burrowing, tropical amphibians. -They occur in tropical forests of South America (their principal home), Africa, India, and Southeast Asia. -Possess a long, slender body, many vertebrae (95 to 285), long ribs, no limbs, tail short or absent, and a terminal anus. -Some possess small dermal scales in the skin. -Eyes are small, missing, or under skin or bone. -Therefore most species are blind as adults. -Instead use a special sensory tentacles on the snout. -Their food consists mostly of worms and small invertebrates, which they find underground.

Crocodilians- Unique characteristic of the head

-A unique adaptation found in crocodilians and mammals, is a complete secondary palate. -This innovation pushed the internal nares to the posterior, allowing a crocodilian to breathe when its mouth is filled with water or food.

Order Caudata

-About 553 species; Means "having a tail". -Salamanders occur in almost all northern temperate regions of the world, and they are abundant and diverse in North America. -Body: head, trunk, and tail, no scales, usually two pairs of equal limbs, and 10 to 60 vertebrae. -Salamanders are carnivorous (both as larvae and adults), preying on worms, small arthropods, and small mollusks.

Salamanders and Newts: Order Caudata (Urodela)

-About 553 species; Means "having a tail". -Salamanders occur in almost all northern temperate regions of the world, and they are abundant and diverse in North America. -Body: head, trunk, and tail, no scales, usually two pairs of equal limbs, and 10 to 60 vertebrae. -Salamanders are carnivorous (both as larvae and adults), preying on worms, small arthropods, and small mollusks.

Thermoregulation

-Amphibians are ectothermic poikilotherms; meaning their body temperature is dependent upon the environmental temperature. -Show dormancy or torpor -The leopard frog and American bullfrog spend the winter underwater. -Some hibernate in winter. -Some frogs dig deep holes into the soil below the frost line. -The spring peeper and wood frog find cracks in logs or rocks. -Estivate in summer (allows survival in extreme desert conditions). -Frogs like the African bullfrog dig deep into the soil just like during hibernation and become dormant.

Classification

-Amphibians are members of Kingdom Animalia, Phylum Chordata, Subphylum Vertebrata, Class Amphibia, Subclass Lissamphibia. -There are Three Orders of Amphibians (more than 6000 species): caudata (Urodela) - Salamanders, newts, and mudpuppies. anura (Salientia) - Frogs and toads. apoda (Gymnophiona) - Caecilians.

Adaptions of Amphibians- Metamorphosis

-Aquatic larva called tadpole goes through metamorphosis to become adult. -Metamorphosis is controlled by a hormone called thyroxine. -Larvae are herbivorous and aquatic, use gills and a two-chambered heart with single-loop circulation. -Adults are carnivorous, can be terrestrial or aquatic, have a three-chambered heart, and can breathe will lungs, gills, or skin depending on the species.

Alligators and Crocodiles- reproduction

-Both are oviparous. -Usually 20 to 50 eggs are laid in a mass of dead vegetation or buried in the sand and guarded by the mother. -The mother hears vocalizations from hatching young and responds by opening the nest to allow the hatchlings to escape. -Unlike other reptiles, crocodilians care for young after hatching.

Adaptions of Amphibians- Pigment Cells

-Called chromatophores. -Three types: Melanophores- black or brown melanin (deep in the skin). Xanthophores- yellow colored (not superficial). Iridophores- reflective or iridescent pigments (superficial).

Adaptions of Reptiles: Excretory System

-Efficient for water conservation. -Paired kidneys excrete uric acid as the main nitrogenous waste. -Water is resorbed in the bladder so "urine" is often a semisolid mass of uric acid. -Salts are removed in many reptiles by salt glands, located near the nose, eyes, or tongue.

Nervous and Sensory System

-Eyelids and lacrimal glands protect and wash eyes. -Nictitating membrane is a transparent membrane that covers the eye when the frog is in the water. -Tympanic membrane for sensing vibrations (hearing). -Paired internal nostrils open into a nasal cavity lined with olfactory epithelium at anterior part of mouth cavity and enable breathing in lung-breathing forms. -Many amphibians are born with lateral lines. As they grow older, some amphibians lose their lateral line because it's no longer a necessity.

Chytridiomycosis

-First identified in 1998, this potentially lethal skin disease is caused by the chytrid fungus, which has been detected on at least 287 species of amphibians from 36 countries. -Chytrid fungus causes dehydration and affects a frog's ability to breathe; it has caused amphibian population declines in Australia, South America, North America, Central America, New Zealand, Europe, and Africa, and is likely responsible for over 100 species extinctions since the 1970's.

Amphibians and The Environment

-Frog populations have been declining worldwide at unprecedented rates, and nearly one-third of the world's amphibian species are threatened with extinction. -Up to 200 species have completely disappeared since 1980. -Amphibian populations are faced with an onslaught of environmental problems, including pollution, pesticides, infectious diseases, habitat loss, invasive species, climate change, and over-harvesting for the pet and food trades.

Differences between frogs and toad

-Frogs: two bulging eyes -Frogs: strong, long, webbed hind feet that are adapted for jumping and swimming VS Toads: stubby bodies with short hind legs for walking or hopping. -Frogs: smooth or slimy skin VS Toads: watery and dry skin. -Frogs: tend to like moist environments VS Toads: usually prefer drier climates parotid (poison) glands behind the eyes. -Frogs: tend to lay eggs in clusters VS Toads: tend to lay eggs in long chains. -Frogs: members of the family ranidae VS Toads: members of the family bufonidae. -Frogs: can be found on every continent expect Antarctica VS Toads: can be found worldwide expect in Australia, though cane toads have been artificially introduced into Australia and some South Pacific islands.

Adaptions of Amphibians- Feeding

-Larvae are herbivores, adults are mostly carnivores. -Digestive system adapted to swallow prey whole. -A true tongue is first seen in some amphibians. -The tongue is attached at the anterior margin of the jaw and lies folded back over the floor of the mouth. -Toad tongues have a sticky tip used as a flip-and-grab feeding mechanism. -Mouth usually large with small maxillary teeth in upper or both jaws. -Frogs have vomerine teeth on the roof of their mouth that are mainly used to hold the prey and keep it in place till they can get a good grip on it and swallow their meal. -Toads, however, do not have any teeth.

Gavials (AKA Gharials)

-Live only in India & Burma. -They are fish eating reptiles with very slender, long snouts. Males have a conspicuous knob at the tip of their snout.

Tuataras- Name Origin

-Means "spiny crest" in native New Zealand language; they have this spiny crest running down center of their back.

Poison Dart Frog

-Members of the Dendrobatidae family, produce toxic skin secretions, some of which are among the most lethal animal secretions known, more dangerous than venoms of sea snakes or any of the most venomous arachnids. -Raised in captivity and isolated from insects in their native habitat never develop venom.

Snake Movements- Lateral Undulations

-Most common -Head moves side to side causing wave of muscular contractions and forwards movement in an S-shaped path.

Lizards General- Characteristics

-Most lizards has movable eyelids -Lizards often rely on speed, agility, & camouflage to catch prey, including insects and small worms. -For protection, lizards may use active displays such as squirting blood, hissing, or inflating bodies. -Some show autotomy - breaking off their tail to escape predators.

Adaptions of Reptiles: Heart

-Most reptiles have a three-chambered heart and double loop blood circulation. -However, crocodilians which require more energy and oxygen, have a four- chambered heart. -Pulmonary loop- blood goes from heart to lungs (to pick up oxygen) back to heart. -Systemic loop- blood goes from heart to body (to deliver oxygen) back to heart.

Vocalization

-Most species have unique sound patterns. -Vocal cords, located in the larynx, or voice box, are much more developed in male frogs (which use their voices to attract mates) than in females. -A frog produces sound by passing air back and forth over the vocal cords between the lungs and a large pair of sacs (vocal pouches) in the floor of the mouth.

Caimans (location)

-Native to Central America and South America but have been introduced in Florida.

Species Spotlight- Mudpuppies

-Necturus maculosus, also called waterdogs, are one of only a few salamanders that make noise. -Easily distinguishable by their bushy, red external gills, which they grow as larva and never lose. -Their bodies are gray or brownish-gray with blue-black spots. -Live on the bottoms of lakes, ponds, rivers, and streams, and never leave the water. -They hide themselves in vegetation and under rocks and logs, emerging at night to feed on whatever prey they can catch, including crayfish, worms, and snails

Adaptions of Amphibians- Respiration

-Presence of gills and lungs varies among species and by developmental stage of some species. -Forms with aquatic larvae lose gills at metamorphosis in frogs. -Many salamanders retain gills and an aquatic existence throughout life. -Double-loop circulation with a three chambered heart (two atria & one ventricle).

Reptiles: Classification

-Reptiles are members of Kingdom Animalia, Phylum Chordata, Subphylum Vertebrata, Class Reptilia -Of the 16 orders of reptiles known to have existed, there are four living orders of Reptiles today (nearly 8,000 species): -Order Testudines: Turtles -Order Squamata ---suborder Sauria: Lizards ---suborder Serpentes: Snakes -Order Crocodilia: Crocodiles and Alligators -Order Rhynchocephalia (Sphenodonta): Tuataras

Adaptions of Amphibians- Reproduction

-Separate sexes (dioecious); predominantly oviparous, some ovoviviparous or viviparous. -External fertilization with amplexus (male clasps back of female as sperm & eggs deposited into water) in frogs and toads. -Internal fertilization via a spermatophore (packet of sperm) in most salamanders and caecilians. -Moderately yolky eggs with jelly-like membrane coverings; Eggs lack complex membranes or shells so they must be laid in water or moist areas. -A few species will care for their eggs by incubating their young in their mouth (Darwin's Frog), on their back (Surinam toad), or stomach (Gastric Brooding Frog).

Lizards- Legless Lizards

A few such as glass lizards are completely limbless.

Adaptions of Amphibians: Reproduction

-Sexes separate (dioecious) with internal fertilization. -Like amphibians, reptiles have a cloaca- a single opening where all waste matter as well as reproductive materials exit the body. -Most male reptiles have two copulatory organs called hemipenes; although they only use one at a time. They are housed internally in males just at the base of the tail, and are everted when needed. -Unlike many other reptiles, alligators use a penis that is always erect and pops out of their bodies to mate. -Visible differences between male and female reptiles are often subtle and reproductive organs are inside their bodies, as a result, it is often difficult to tell if you have a male or female reptile with just a glance.

Adaptions of Amphibians- Skin

-Smooth, thin, moist, glandular skin with no scales. -Contains keratin to prevent water loss. -Many have small mucus glands embedded in skin to keep skin moist; must remain moist to take in dissolved oxygen for cutaneous respiration (skin breathing). -Supplied with blood vessels. -Some have large granular serous glands to secrete a white, watery poison or a foul tasting substance for defense. -All amphibians produce a skin poison, but its effectiveness varies among species and with different predators.

Why amphibians are important

-Tadpoles keep waterways clean by feeding on algae. -Adult frogs eat large quantities of insects, including disease vectors that can transmit fatal illnesses to humans (i.e. mosquitoes/malaria). -Amphibians also serve as an important food source to a diverse array of predators, including dragonflies, fish, snakes, birds, beetles, centipedes and even monkeys. -Frogs produce a wide array of skin secretions, many of which have significant potential to improve human health through their use as pharmaceuticals. -Similar to 'Canaries in a coal mine', they are bioindicators; being especially susceptible to environmental disturbances, amphibians are considered accurate indicators of environmental stress: the health of frogs is thought to be indicative of the health of the biosphere as a whole.

Terrapins: Order Testudines (Chelonia)

-Terrapins spend their time both on land and in water, and live along rivers, ponds, and lakes. -Terrapins are often found in brackish, swampy areas.

Snakes- Eye & Ear Anatomy

-The cornea of a snake's eye, lacking a movable eyelid, is permanently protected with a transparent membrane called a spectacle, which, together with reduced eyeball mobility, gives snakes the cold, unblinking stare that many people find frightening. -Most snakes have relatively poor vision. -Snakes have no external ears or tympanic membrane but are quite sensitive to vibrations carried in the ground.

Species Spotlight- Chinese Aquatic Salamander

-The giant salamanders of China (Andrias davidianus) and Japan (A. japonicus) are by far the world's largest amphibians. -Traditionally valued for food, their current decline is being driven by hunting.

Anura Statistics

-The largest anuran is the West African Goliath frog, Conraua goliath, which is more than 30 cm long from tip of nose to anus. It eats animals as big as rats and ducks. -The largest American frog is the American Bullfrog, Rana catesbeiana, which reaches a head and body length of 20 cm. Bullfrogs in captivity do not hesitate to snap at tormentors and can inflict painful bites. -The world's smallest known vertebrate Tiny frog Paedophryne amauensis is 7.7 mm in length. It was discovered in Papua New Guinea in August 2009 and formally described in January 2012.

Snakes- Jaws

-The two halves of the lower jaw (mandibles) are joined only by muscles and skin, allowing them to spread widely apart. -Since a snake must keep breathing during the slow process of swallowing, its tracheal opening (glottis) is thrust forward between the two mandibles. -Swallowing may take several hours but saliva begins digestion during swallowing.

Crocodilians- History

-They are the most closely related to dinosaurs. -The only surviving reptiles of the archosaurian lineage that gave rise to the great Mesozoic radiation of dinosaurs and birds. -They also differ little in structural details from primitive crocodilians of the early Mesozoic.

Tortoises: Order Testudines (Chelonia)

-Tortoises are land-dwelling and tend to have dome-shaped shell to retract their head & limbs. -They have thick sturdy legs and feet for moving on land and eats low-growing shrubs, grasses, and even cactus. -Land tortoises are slow; some of them walk at only 0.5 miles per hour. -Tortoises that live in hot, dry habitats use their strong forelimbs to dig burrows. Then, when it's too hot in the sun, they slip underground.

Adaptions of Reptiles: Skin

-Tough, dry scaly skin that offers protection against desiccation (drying out) and physical injury. -Skin has a keratinized epidermis and a thick, collagen-rich dermis with chromatophores for color and lipids to prevent drying out. -Reptiles have a unique form of keratin called beta keratin to provide additional protection.

What kind of snakes inject venom? What kind of venom do they inject and what does it do? List venomous snakes

-Water moccasin & rattlesnake use Hemotoxin; poisonous proteins that attack red blood cells. Copperheads use Neurotoxin; poison that works on nervous system affecting heart rate & breathing. - Examples: Cobra, Viper, Copperhead, Rattlesnake

Reptiles: Life on Land (reproduction)

-While amphibians are able to come on land, their shell-less eggs, thin, moist skin, and gilled larvae prevent most from ever being fully terrestrial. -The first animals adapted to life entirely on land. -They gained that title because they do not need water to reproduce. Reproduction without water is accomplished by a structure called the amniotic egg. -Animals with an amniotic egg are called amniotes.

Lizards- Chameleons

A group of arboreal lizards, mostly of Africa and Madagascar. They catch insects with a sticky-tipped tongue that can be projected accurately and rapidly to a distance greater than the length of their body. Also can change colors for protection.

Transitional Fossils: (4)

1.) Eusthenopteron 2.) Tiktaalik 3.) Acanthostega 4.) Ichthyostega

Adaptions of Reptiles: Body Temperature

Amphibians and reptiles are both poikilothermic ectothermic tetrapods, relying on the environment for adjustment of their body temperature.

Adaptions of Reptiles: Lungs

Better developed lungs; reptiles lungs have more surface area than the lungs of amphibians and are ventilated by drawing air into the lungs by expanding the rib cage (lizards and snakes) or moving internal organs (turtles and crocodiles).

Adaptions of Reptiles: Brain

Complex brain with an enlarged cerebrum, used to interpret sensory information and control muscles during movement.

When did lizards first appear?

Cretaceous Period

Crocodiles VS Alligators- Habitat/Location & Head Morphology

Crocodiles are tropical or subtropical, usually nocturnal, reptiles found in Africa, Asia, South America, & extreme southern Florida. -Long triangle-shaped heads; when mouth is closed you can see the upper and lower teeth showing; teeth vary in size. Two species of alligators are found in China & the southern United States. -Wide flat heads with round noses; When mouth is closed only the upper teeth are showing; Teeth vary in size.

What preadaptations of fish led to amphibians

Fleshy fins with strong bone structure, nostrils, and lungs.

Adaptions of Amphibians- Digestive Tract Organs

Food travels from the mouth 🡪 esophagus 🡪 stomach 🡪 small intestines 🡪 large intestine (colon) 🡪 cloaca.

Ichthyostega

Fully developed shoulder girdle, bulky limb bones, well-developed muscles, and other adaptions for terrestrial life.

Lizards Venomous

Gila monsters, and their close relatives, beaded lizards, are the only lizards capable of delivering a venomous bite.

Difference between boas and pythons (habitat/location, reproduction, size)

Habitat/Location: -Pythons are found in Africa, Asia, and Australia while boas also live in those places but also North, Central and South America. Reproduction: -Pythons lay eggs while boas give birth to live young. Size: -Boas are 2 feet long when they are born but will keep growing during their life. Pythons can grow to be 23 feet long and weigh 200 pounds.

Venomous Snakes- Fangs

Have 1 of 3 types of fangs: -Rear-fanged snakes, such as the boomslang, bite prey & use grooved back teeth to guide venom into puncture wound. -Front-fanged snakes, such as cobra, inject poison through 2 small front fangs that act like a hypodermic needle. -Hinged- fang snakes, such as rattlesnake, water moccasin, and copperhead, have hinged fangs in roof of mouth that swing forward to inject poison.

Lizards- Skinks

Have elongate bodies, an armor of tight-fitting osteoderms, and reduced limbs in many species.

Tiktaalik

Intermediate between lobe-finned fish and tetrapods.

What is a kinetic skull in lizards and snakes?

It is modified to have movable joints, used for eating large prey.

Excretion

Kidneys filter liquid waste as urine. Kidneys 🡪 ureters 🡪 small urinary bladder 🡪 cloaca Unlike fish with different exit openings for wastes and reproductive cells (eggs, sperm); most amphibians have only one exit called the cloaca. Waste from kidneys and urinary bladder, as well as sperm or eggs all leave through this opening.

Lizards- Monitors

Large, active predators that include the largest lizard, the Komodo dragon

Eusthenopteron

Late Deonian lobe-finned fish had an upper arm bone and two forearm bones and some wrist bones.

Snake anatomy

Limbless; usually lack both pectoral and pelvic girdles; well known for their extreme elongation of their body and accompanying displacement and rearrangement of internal organs.

Alligators- Unique reproduction characteristics

Male alligators make loud bellows during the mating season.

Adaptions of Amphibians- Limbs & feet

Most have 4 limbs- webbed feet or claws on toes.

Do turtles have teeth? if not, what do they use?

No, but its jaw is composed of tough, kerantized plates forming a beak, which can be used for gripping food.

Lizards- Iguanas

Often brightly colored with ornamental crests, frills, and throat fans.

Acanthostega

One of the earlierst known Devonian tetrapofd, well formed tetrapod limbs with clearly former digits on both forelimbs and hind limbs.

What is the turtles shell composed of?

Outer layer- keratin Inner layer- bone - the bony layer is fused to the ribs and vertebrae inside the shell.

Difference between oxygen content between living on land vs water

Oxygen is 20x more abundant in air and diffuses more rapidly through air than through water. Terrestrial animals can obtain oxygen for more easily than aquatic ones once they possess lungs and other appropriately adapted respiratory structures.

What period is nicknamed the "Age of Amphibians?" When was it?

Permian Period; 286-249 million years ago

Turtles- senses

Poor hearing but good sense of smell, acute vision, and color perception.

Lineage

Reptiles as form a paraphyletic group because they do not include all descendants of their most recent ancestor.

How do constrictors kill their prey? What are some common constrictors

They wrap their body around the prey and squeeze them to death. -boas, pythons, anacondas

Adaptions of Amphibians: Skull

Skull structure also varies among reptiles and other vertebrates. There are three main skull designs: -Anapsid: Have no openings behind eye socket; Seen in turtles. -Synapsid: Has a single opening, called a fenestra, behind eye socket. Seen in mammals. -Diapsid: Have two fenestrae behind eye socket. Seen in all reptiles (except turtles) and birds.

Lizards- Geckos

Small, agile, mostly nocturnal forms with adhesive toe pads that enable them to walk upside down and on vertical surfaces.

Reptiles: Amniotic Egg

The amniotic egg is different from fish and amphibian eggs because they have four extra membranes: -Amnion: thin membrane enclosing the fluid in which the embryo floats. This fluid serves to cushion the embryo and prevent dehydration. -Allantois: stores metabolic wastes produced by the embryo. -Yolk Sac: encloses the yolk, a fat-rich food supply for the developing embryo. -Chorion: outermost membrane of the egg; surrounds all other membranes. Helps protect embryo and allows oxygen to enter egg while removing carbon dioxide. -Reptile eggs also contain albumen, which is additional protein and water; this is like the egg white of a chicken egg. -Most amniotic eggs are surrounded by a mineralized but often flexible shell. -Reptile eggshells are described as being leathery, while bird eggs are hardened. Most mammals lack shelled eggs. -To help reptiles breaking open their shell to hatch, many have a horny tooth on their snout. The tooth drops off shortly after hatching.

What are animals with four legs called? Where does that come from?

Tetrapods Greek word "tetrapoda" meaning "four legs"

What is the "Age of Reptiles" called and when was it?

The Mesozoic Era; 245 to 65 million years ago

Snake Movements- Sidewinding

The head is vigorously flung from side to side; this whip-like motion moves body along. (sideways movement of body) -used by some desert snakes.

How can many snakes, including rattlesnakes and pit vipers, hunt in complete darkness?

The heat-sensitive pits on each side of the snake's head will detect the heat from the prey, and nerves transmit this information to the same area in the brain that receives optic nerve impulses. -It is accurate to say the snake "sees" a heat image of its prey, and it can strike in darkness if the prey is even slightly warmer than its background.

Species Spotlight- Hellbender

The largest aquatic salamander in the US, the Hellbender (Cryptobranchus alleganiensis) can grow as long as two feet.

Snakes- Jacobson's Organ

The olfactory areas in the nose are not well developed but they detect chemicals (smell/taste) using their forked tongues and Jacobson's organs (pit-like organs in the roof of the mouth).

Adaptions of Amphibians: Skeleton

The reptilian skeleton differs from other vertebrates in various ways: -Reptiles have several bones in their lower jaw that enable them greater bite mobility. -Reptiles have only one bone in each ear (the stapes). -Reptiles also have only one occipital condyle (a protrusion on the skull that forms a joint that enables movement of the head) while mammals and amphibians have two occipital condyles.

Turles: Order Testudines (Chelonia)

The terms "turtle," "tortoise," and "terrapin" are applied variously to different members of the turtle order. In North America: -Turtles are usually water-dwelling and have streamlined, disk-shaped shells and webbed feet or flippers to rapidly move in water. They swim, but they also climb out onto banks, logs, or rocks to bask in the sun. In cold weather, they may burrow into the mud, where they go into torpor until spring brings warm weather.

When did modern amphibians start appearing?

Triassic Period

When did turtles appear?

Triassic Period; 200 million years ago