iii) Reptiles-Dinosaurs By: Camila Rodriguez

Dinosaurs  Not the first reptile  Triassic period  Cretaceous period  Diapsid skull

Reason for the name  From the Latin word 'reptilis'  Means 'creeping’ # of species currently existing  9,475 species  Divided in 4 groups: Crocodilia, Squamata, Testudines and Sphenodontia.  Crocodilia: alligators, crocodiles, caimans and gharials.  Squamata: Snakes and Lizards  Testudines: tortoises and turtles  Sphenodontia: tuataras

CrocodiliaSquamata TestudinesSphenodontia

Reptile characteristics  Vertebrates=have backbone/internal skeleton  Cold blooded  Lay eggs on land (amniote eggs)  Get oxygen from lungs  Dry scaly skin  Hatch into young adults  3 chambered heart (alligators and crocodiles)  2 aortic blood vessels  4 or no legs  Internal fertilization

“Fossil record”  Oldest fossil 315 million years - Hylonomus (late Carboniferous period)

Life Cycle  Some lay their eggs and some give live birth. (oviparous)  Some reptiles stay with their parents when born  Grows becoming an adult  Female fertilize internally producing the eggs  They can reproduce more than once  After giving birth they die  Asexual reproduction

Life Expactancy  Giant Tortoise: 152 years  Box Turtle 123 years  Alligator 68 years  Snapping Turtle 57 years  Cobra 28 years  Cottonmouth 21 years

Digestive System  Very simple  Mouth  Salivary gland- softens and moistens food  Esophagus- a tube in which the food goes from the pharynx to the stomach  Intestine- from stomach to anus  Cloaca- outlet into the intestinal, urinary, and genital open  Eat  Most reptiles are carnivores feed on small invertebrates (mammals, reptile)  Some are herbivores feed on plant such as grasses, fruits, shrubs and marine plants.

Respiratory System  Breath using lungs  Gas exchange in reptiles occurs in the alveoli ( diaphragm)  Breathing occurs in a change in the volume of the body cavity.  Controlled by contraction of intercostal muscles.  Turtles and tortoise  Ventilation of the lungs  sheets of muscle in the shell that, through contraction and relaxation, force air in and out of the lungs

Circulatory System  Closed system  3 chambered hearts with two atria  Blood flows through heart  Mixing of oxygenated and deoxygenated blood

Sensory System  They feel pain, temperature, pressure, and stretching at the dermal level.  Crocodilia  Vertical cat-like pupil excellent diurnal / nocturnal vision  External ears  Eardrums  Nostril  Squamata  Eyelids- spectacle  Smell with their tongue  Ears  Testudines  smell  Ears: only hear vibrations and changes in water pressure  Night vision

 Sphenodontia  Great vision  Third eye  Weak taste buds Sensory System

Bibliography   es.htm es.htm  Reptiles Reptiles  +Sensory+Systems +Sensory+Systems   /Digestive-and-urogenital-systems /Digestive-and-urogenital-systems 