Amphibians and Reptiles

Amphibians Classification/ Taxonomy Kingdom: Animalia Phylum: Chordata: Has a backbone Superclass: Tetrapoda: Means 4 footed Class: Amphibia

Basic Characteristics of Amphibians Tetrapod vertebrates Most live in terrestrial, forest, damp or freshwater aquatic ecosystems Most go through metamorphosis during their life- cycle Require water in order to reproduce Ectothermic

3 Orders of Amphibians Order Anura: Frogs and Toads Anura means “without tail” Webbed toes No claws or tails Large eyes Moist skin that many of them breath through

Order Caudata: Salamanders and Newts Resemble lizards but do not have scales (have smooth skin) Lack claws Tails are flat or finned Range in size from 0.8 inches (Mexican Thorius Pennatulus) to 1.8 meters (Chinese Giant Salamander)

Order Gymnophiona: Caecilians Long, limbless snake/worm-like animals Grow to be between 3 cm and 4.9 feet long Most live underground in damp soil

Amphibian Skin (Integumentary System) Most shed a thin outside layer of their skin periodically-molting Skin allows water in and out Gas exchange can occur through their skin (breathes through skin) Have mucus glands that produce foul tasting or poisonous toxins to ward off predators. Many amphibians have chromatophore pigments and can change their skin color but it happens slowly. The color change is controlled by hormones.

Skeletal System Similar to other tetrapods 4 limbs (except caecilians) Bones are hollow and light weight Bones are fully ossified with Calcium Have 4 toes on the front feet and 5 toes on the back feet.

Life Cycle/ Reproduction Most amphibians go through metamorphosis. 1. Most frogs have external fertilization while salamanders and caecilians have internal fertilization. 2. Eggs are jelly-like and must be laid in water to prevent drying out 3. Eggs develop into larva/ tadpoles that live in the water and have gills and tails 4. Arms and legs of tadpole grow as tail reduces in size by reabsorption (it does not fall off) 5. Lungs Develop

Other Amphibian Characteristics Amphibians are predators using their tongue to catch prey. Their diet is mostly small insects like beetles, caterpillars, earthworms and spiders. Frogs are vocal during mating season with the male “calling out” to attract females. Some frogs produce toxins and have a warning coloration to warn potential predators.

Reptiles

Reptile Classification and Taxonomy Kingdom: Animalia Phylum: Chordata Class: Reptilia Common Characteristics Tetrapod Has scales covering their skin Ectothermic Shed their skin periodically as they grow

4 Subgroups of Reptiles Testudines: Turtles, Terrapins and Tortoises Bony or cartilaginous shell that develops from the ribcage Live in water Terrapins Have shell Smaller than most turtles Tortoises Live on land

Sphenodonita: Tuatara Only found in New Zealand Only 2 living species of Tuatara are left Similar to lizards but evolved separately

Squamata: Lizards and snakes Approximately 6,000 species Have feet and external ears Tails can detach and regrow Snakes Legless Skulls have many joints so they can swallow large prey

Crocodilia: Crocodiles, Gavials, Caimans and Alligators More narrow head than Alligators and Caimans Upper and lower jaw are the same width Can see all of their teeth on the outside when they close their mouth Gavials: Have a long narrow snout Caimans: Smaller and are closely related to alligators Alligators Only 2 living species: American and Chinese Alligators Lower jaw is larger than the upper jaw Teeth fit into grooves when they close their mouth so you cannot see their teeth when they close it

Reptile Body Systems Circulatory System Respiration Digestion 3 chambered heart Ectothermic Respiration Breaths using lungs Aquatic turtles have permeable skin Digestion Most reptiles are insectivores or carnivores Short digestive tract because meat is easy to break down

Reproduction Most reptiles have sexual reproduction though a few species can reproduce asexually through parthenogenesis. Reptiles are oviparous and have internal fertilization. The females then lay the fertilized egg. Amniotic Egg: egg is covered with leathery or calcified shell that: Protects the embryo Keeps it from drying out Yolk nourishes embryo Allows for gas exchange.