Reptiles!!!. Classification Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Class: Reptilia...
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Transcript of Reptiles!!!. Classification Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Class: Reptilia...
Reptiles!!!
Classification
• Kingdom: Animalia• Phylum: Chordata• Subphylum: Vertebrata• Class: Reptilia– Orders:• Crocodilia• Sphenodontia• Squamata• Testudines
Characteristics
• Ectothermic(Cold-blooded)• Regulate body temperature by seeking
or avoiding sun.• Air Breathing • Tetrapods• Scales instead of feathers or hair• Three and a half chambered hearts• Most lay eggs• Amniotes!
Evolutionary Milestone
• The Amniote Egg– Adapted for land.– Allows for full
development inside safety of egg.
Reptile History
• First reptiles appeared around 380 million years ago, during the Pennsylvanian time period, when the climate was warm and humid, and amphibians dominated.
• Many different reptile species appeared during the Triassic, which had a drier, cooler climate.
• Today, 6,500 species of reptile walk and slither on the Earth, and reside on every continent, except Antarctica.
The Four Reptilian Orders
CrocodiliaTestudines
Squamata Sphenodontia
Sphenodontia
• 2 species of Tuatara living in New Zealand; all others went extinct 60 mya.
• Has not changed in 225 million years
• Living fossil!• They have a 3rd
“eye”, have no external ear openings, and males lack a penis.
Crocodilia
• Appeared 85 mya• Large reptiles with
elongated head• Alligators,
Crocodiles, Caimans, and Gharials
• 4 Chambered Heart• Teeth in bony socket• Closest living
relative to birds.
Testudines
• Turtles and Tortoises
• Bodies with two-piece bony shell – Carapace: dorsal;
arose from ribs– Plastron: ventral
• Appeared in fossil record 220 mya
Squamata
• Lizards and snakes• 5640 species!• Tough epidermal
scales made of keratin
• Possess moveable quadrate bone.
• Most variable order in size