Characteristics

Characteristics

1. Reptiles

   • Vertebrates (have a backbone)
   • Young produced from eggs
     • Oviparous (lays the eggs)
     • Ovoviviparous (holds the eggs inside the body until the young hatch)
     • Viviparous (develops a placenta for live birth)
   • Cold blooded
     • Requires external heat to maintain body temperature
       • Become inactive without adequate environmental heat
   • Covered by scales

2. Testudines (Turtles)

   • Lay eggs
     • No parental care of the young
   • Sex of individuals is determined by the temperature of eggs developing in the nest
   • Three types:
     • Marine
     • Fresh water
     • Terrestrial
   • Long-lived

3. Squamata (snakes and lizards)

   • Most are terrestrial
     • Some are secondarily aquatic (mostly snakes)
   • Bodies are covered with scales
   • There are thousands of species of snakes and reptiles

4. Amphibia

   • Lepospondyli
     • Extinct
   • Labrinthodontia
     • Extinct
   • Lissamphibia
     • 3 orders of animals
       • Order Anura - frogs and toads (tailless)
       • Order Apoda - Caecilians (legless animals)
       • Order Urodela - newts and salamanders (have a tail)
     • Most measure less then 30cms
     • Skin is moist with a profusion of mucous glands
     • Outer skin is shed periodically
     • Four toes on the hand
     • Teeth are not complex
     • Parts of the skeleton can be cartiliginous
   • Ectothermic
   • Tetrapods (four limbs)
   • Two distinct life phases (tadpole/frog)
   • Have gills for at least part of their life
   • Spend at least part of their lives in water and on land
   • Cutaneous respiration (can exchange gasses through skin surface)
   • Two types of skin glands
     • Mucous for cutaneous respiration
     • Parotid glands for toxic secretions in toads
   • Oviparous (usually lay eggs in an aquatic environment)