Reptiles

Characteristics Allowed Reptiles to be terrestrial Scales clawed toes Ectothermic internal fertilization amniotic egg

Movement: legs not directly under body so they move slower than mammals Vision important. Movable eyelids Ectothermic – cannot live in extremely cold regions. Cannot warm eggs

Lungs with large surface area (Snakes – only have one lung) Heart almost in 4 chambers. No septum so some mixing of O 2 rich and O 2 poor blood

Reproduction Internal fertilization which protects gametes from drying out Amniotic egg Oviparous – mother lays eggs then young hatch Ovoviviparous- Fertilized egg hatches in mother

Amniotic Egg Has a leathery protective shell that keeps the eggs from drying out. Eggs can be laid on land Shell and several membrane layers provide protection to embryo from environment Yolk made of nutrients – supplies nourishment to embryo Reptiles completely develop inside the egg before hatching

Groups Turtles and tortoises Tuataras Crocodillians Lizards and Snakes

Tuataras Found in New Zealand. Looks like a lizard. Has not changed much in 150 million years (living fossil)

Crocodilians- Crocodiles, Alligators, Caimans Aggressive carnivores Very sharp teeth and strong jaws. Haul prey to water and drown them. Care for their young

Lizards and Snakes Lizards Lizards have legs and snakes do not. Snakes are lizards without legs. Evolved from lizards. Herbivores and carnivores

Order Squamata – Lizards & Snakes Gave rise to the mammals Lizards: legs, clawed toes, external ears, moveable eyelids, herbivore and carnivore Snakes: lizards that lost their legs during evolution, carnivore

Lizard and Snakes cont. Snakes Hybrid python and snake – history channel Have no eardrum. They feel the ground vibrations. Only one lung Tongue “Tastes” the air. How they smell Pit organs detect heat Mother may stay with eggs Snakes swallow prey whole Contrictor venemous

Turtles and tortoises Spine fused to top shell (carapace) Bottom of shell called a plastron Some are herbivores. Some carnivores. Do not care for young. Vertebral column fused to carapace except for neck and tail All oviparous with no parental care

Igguina the Igguana Hemipenes (two penises)..some snakes, not turtles, some lizards (not Igguanas) Jacobson’s organ- tongue “tastes” and touches the organ in the top back of mouth for analysis Nostrals- sneezing is for salt elimination Parietal eye- on top of head. Used for UV detection. UV=calcium absorption

Iggy Cont: Arboreal digs for nesting Eggs- produced…can be reabsorbed or layed Fat storage- in tail and behind eyes Color change- when happy or warmer Teeth- serrated but only eats plants