characteristics of reptiles class reptilia includes snakes, lizards, crocodiles, alligators and...

Characteristics of Reptiles

Characteristics of ReptilesClass Reptilia includes snakes, lizards,

crocodiles, alligators and extinct dinosaurs.The majority of reptiles are terrestrial and

are adapted to a wide range of habitats.

Crocodile or alligator?

Gila monsterHeloderma suspectum

Characteristics of ReptilesEvolved from amphibians about 350 million

years ago and dominated the Earth between 245 million and 65 million years ago—the Age of Reptiles (Mesozoic era).

Characteristics of ReptilesAdaptations to terrestrial life include their

dry, scaly skin (resistant to water loss and wear and tear) and their amniotic egg (consists of a hard shell and multicellular membranes, which encase the embryo in a secure, self0contained aquatic environment).

Characteristics of ReptilesAre ectothermic. Regulate

their body temperature by controlling how much heat they absorb.

Use lungs for respiration and have a circulatory system composed of two loops and a 3-chambered heart, in which one chamber is partially divided.

Characteristics of ReptilesMore advanced nervous

system than amphibians. Most have a highly-developed sense of smell. Are equipped with a specialized organ sensitive to low concentrations of odors called the Jacobsen’s organ, located in the roof of the mouth.

Characteristics of ReptilesExcrete nitrogenous wastes in the form of

uric acid. In the body, uric acid is much less toxic than ammonia or urea. Thus, it requires little water for dilution, and reptiles lose only small amounts of water in their urine.

Characteristics of ReptilesMore than 5,000 species of modern reptiles

divided into 4 orders:1. Order Testudines: turtles, tortoises, and

terrapins.

Terrapene ornata Box Turtle: Geochelone nigra vicina

Galapagos tortoiseDiamondback TerrapinMalaclemys terrapin

Orders of Reptiles2. Order Squamata: lizards and snakes.

Anole: Anolis carolinensis

Corn snake: Elaphe guttata

Orders of Reptiles3. Order Crocodilia: crocodiles and alligators.

American AlligatorAlligator mississippiensis

Siamese crocodileCrocodylus siamensis

Orders of Reptiles4. Order Rhyncocephalia: tuataras

Sphenodon punctatus

Encloses the yolk

A fat-rich food supply

Contains proteins and water needed by embryo

Stores nitrogenous wastes produced by embryo Surrounds all

membranes and cushions developing embryo

Thin membrane enclosing the fluid in which embryo floats

Provides protection from damage and evaporation of water from egg

Characteristics of Amphibians

Characteristics of AmphibiansModern amphibians share several key characteristics:Most species

change from an aquatic larval stage to a land adult form. This transformation is called metamorphosis.

Characteristics of AmphibiansMost have moist, thin skin with no gills.Skin is equipped with numerous mucus

glands that supply a lubricant that keeps the skin moist in air.

African Reed Frog

Characteristics of AmphibiansLarvae exchange oxygen and carbon dioxide

through their gills and skin. Most adults lose their fills and respire through lungs and skin.

Characteristics of AmphibiansAll adult amphibians are carnivorous, with

insects and other arthropods as the most commonly consumed prey. Most amphibian larvae are herbivores, feeding on algae, bacteria, or tiny green plants.

Characteristics of AmphibiansAre ectothermic (external-heat).

(Amphibians are ectothermic, which means their blood temperature rises and falls with that of the surrounding environment)

Characteristics of AmphibiansMost have 4 pairs of limbs. Feet, if present,

lack claws and are often webbed.

Characteristics of AmphibiansAre oviporous. Eggs lack multicellular

membranes or shells. They are usually laid in water or in moist places and in most species are fertilized externally.

Characteristics of AmphibiansMany show parental care, guarding their

eggs and keeping them moist.

Poison Arrow Frog

Characteristics of AmphibiansCloaca are the

primary excretory organs.A muscular cavity at

the end of the large intestine through which digestive wastes, urine and eggs or sperm leave the body.

Characteristics of AmphibiansA 3-chambered heart. Does not mix oxygen

and deoxygenated blood very much. Little mixing increases the amount of oxygen that is delivered to the tissues.

Characteristics of AmphibiansThe amphibian circulatory system is divided

into two separate loops. One loop carries blood between the heart and lungs. The other loop carries blood to the organs and tissues in the body and returns it to the heart. This “double loop” circulation delivers blood to the body faster. Double-loop circulation occurs in amphibians and is now used by them and all other vertebrates.

Characteristics of AmphibiansThe senses of hearing, smell, and sight are

well-developed in most amphibians. Sound receptors are located in the inner ear, which is embedded within the head. Sounds are transmitted to the inner ear by the tympanic membrane, or eardrum.

Characteristics of AmphibiansThe olfactory lobes, which are the center of

the sense of smell, are larger in amphibians than in fish. The eyes can blink and are covered by a transparent, movable membrane called a nictitating membrane. Additionally, there is a continuous communication among most areas of the body.