Nonavian Diapsid Amniotes Reptiles Nonavian Diapsid Amniotes
Taxonomy Kingdom: Animalia Phylum: Chordata Subphylum: Craniata Infraphylum: Vertebrata Class: Reptilia
Evolutionary Adaptations Evolved ~ 350 mya Able to live on land….thanks to the amniotic egg Amniotic Egg Extraembryonic membranes to… Protect the embryo from desiccation (drying out) Cushion the embryo Promote gas transfer Store waste materials Leathery or hard shells for protection Albumen for cushion, moisture, & nutrients Yolk supplies the food
Reptile Adaptations to… Life on Land Amniotic Egg Impervious skin Horny nails- used for digging & locomotion Water-conserving kidneys Enlarged lungs Loss of lateral-line system
Reptile Characteristics Thick, dry, & keratinzed skin (covered in scales) May secrete pheromones through their skin for sex recognition & defense Shed their skin (ecdysis) Due to low blood flow to the outer layer of skin Skin may be colored for sex recognition, mimicry, and for cryptic purposes
Reptile Characteristics Skeleton: Longer skull- development for breathing and better smell More cervical vertebrae for head movement Ribs modified Fused to create the shell in turtles Muscular connections for movement in snakes Tail vertebrae may possess a fracture plane Can break their tail off when threatened
Reptile Characteristics Nutrition & Diet Carnivores Except turtles (may be carnivores, herbivores, or omnivores) May have sticky tongues for catching prey May extend the length of their body Skull and jaw bones may spread apart to allow room for bigger prey
Reptile Characteristics Circulation, Gas Exchange, & Temperature Regulation 3 chambered heart 2 atria & 1 ventricle Ventricle is partially divided (completely divided in crocodiles) Breathe with lungs Thermoregulate with external heat sources (ectothermic) Tend to bask in sunlight for warmth
Reptile Characteristics Nervous System Developed brain Vision is the dominant sense Upper & lower eyelids and nictitating membrane May detect light with a median (parietal) eye Jacobson’s (vomeronasal) organs- olfactory organs Connected to the forked tongues in snakes
Reptile Characteristics Reproduction & Development Dioecious Internal fertilization Sex organs contained inside of the cloaca Courtship behavior is species specific Mother abandons eggs after she lays them Alligator nest temperature determines gender of young <31.5C= females 32.5-33 C= males 32 C= males & females
Class: Reptilia Order: Testudines Carapace Turtles Characteristics: Bony shell Limbs articulating internally to the ribs Keratinized beak rather than teeth Shell Dorsal=carapace Ventral=plastron Plastron
Class: Reptilia Order: Testudines North American box turtle Shell has hinges to allow the anterior & posterior regions to raise up or down The shell closes when the turtle pulls in it’s head & tail
Class: Reptilia Order: Testudines Long life spans Large tortoises live >100 years Reach sexual maturity between 7 & 8 years Oviparous- lay eggs Females dig out nests in the soil Cover the 5-100 eggs with soil Eggs take 4 weeks to 1 year to develop Young are independent from parents (no parental care)
Class: Reptilia Order: Testudines Turtles vs. Tortoises Turtles- aquatic & have webbed feet Tortoises- terrestrial & do not have webbed feet Conservation Turtles are vulnerable due to… Slow growth rates Long juvenile periods Nearing extinction thanks to young turtle predators & turtle hunters
Class: Reptilia Order: Crocodylia Alligators, crocodiles, gavials, & caimans Derived from archosaurs (ancient reptiles) Triangular eye orbits Laterally compressed teeth Mildly evolving over the past 170 my Nostrils are at the tip of the snout (can breathe while mostly submerged) Muscular & elongated tail Swimming, offense, defense, & attacking prey Swallow food whole Oviparous & take care of their young
Class: Reptilia Order: Squamata Lizards 2 pairs of legs Upper & lower jaws unite anteriorly Geckos- nocturnal & can vocalize with clicking sounds Iguanas- can glide from a tree for at least 30 m Chameleons- arboreal & consume insects Change color in response to illumination, temperature, & behavioral state Gila monster- venomous lizard Southwest U.S. Venom released when they chew (not fatal to humans)
Class: Reptilia Order: Squamata Snakes 2,900 species (300 are venomous…not poisonous!!!) Scale patterns can determine whether the snake is venomous or not 30,000 people die a year from snake bites (mostly in SE Asia) Only 9-15 die from snake bites each year in the U.S. Long & lack limbs May contain more than 200 vertebrae May swallow large prey whole (movable jaw)
Class: Reptilia Order: Squamata Worm Lizards Live in the soils of Africa, South America, the Caribbean, & the Mideast Legless Single median tooth in the upper jaw Ringlike folds in the skin (annuli) Easily move forwards or backwards