Class Amphibia, Class Reptilia, and Class Aves 17C and 17D PAGES 520-541

Class Amphibia Amphibian means “double life” – a water life and a land life They hibernate (sleep deeply for a long time) in cold weather Three Orders: Order Apoda – look like worms and live underground caecilians Order Caudata – small body with 4 limbs (legs) – salamanders Order Anura – large head, no tail, short front legs with big back legs - frogs

Metamorphosis of Amphibians All amphibians lay eggs in the water. They live in the water until they are teenagers (tadpoles) As adults, they live on the land (frogs) Their skin is smooth and soft Amphibians have both gills and lungs – the gills will disappear when they become adults – they use the gills in the water before they become adults

Circulatory System of Amphibians Amphibians have 3 parts to their hearts – called “chambers” There is an extra loop the blood goes through before going to the body, the same as a human (not like a fish) The blood goes: heart – lungs – heart – body

Class Reptilia

Class Reptilia Snakes, lizards, turtles, alligators, crocodiles They have thick skin with scales Most live on the land, but near water or in wet areas (mud) Most lay eggs that hatch later (oviparous) Many hibernate (sleep deeply for a long time) in the cold Use lungs with alveoli (inside of the lung that works better than a frog) to breathe

Class Reptilia Reptilia have stronger hearts with 4 chambers instead of 3 (like the amphibians) Snakes and some lizards have Jacobson’s organs – part of the top of the mouth that smells the air and lets the snake know what is nearby

Orders of Class Reptilia Order Squamata Disarticulating lower jaw (it comes apart to eat bigger things) Some venomous species (can have poison) Snakes and lizards Some snakes have fangs (big teeth)

Orders of Class Reptilia Order Testudinata Have a protective shell Carapace (back) and plastron (front) Turtles and tortoises Order Crocodilia Alligators and crocodiles Order Rhychocephalia Spines (like needles) on the backs of the head Tuatara (lives in New Zealand only

Class Aves

Class Aves All birds, including penguins and ostriches They have hollow bones – there is nothing inside the bones, like a straw They have feathers and beaks (mouths) They have different kinds of feet Webbed – used for swimming, like a duck or a penguin Talons – claws, like an eagle

Kinds of Feathers Birds have 2 main kinds of feathers 1.) Down Feathers – they are soft and keep the bird warm 2.) Contour feathers – cover most of the bird and give the bird shape and color Flight feathers let the bird fly – they cover the bird from the wings to the tail and are very strong

Digestion in Birds Birds have a crop – a place where the food waits inside the bird to be digested (turned into energy) Birds have a proventriculus – a place where chemicals in the bird are put onto the food to break the food down Birds have a gizzard – after a bird eats stones and sand, the wet food from the proventriculus is smashed against the stones and to break the food down

Other Bird Parts Birds cannot get enough oxygen from their lungs, so they have air sacs – an extra place for air to go into the bird and for oxygen to get to the bird’s blood Birds also have a syrinx – this is in their throats and lets them sing

Bird Reproduction Male birds are usually bigger and more beautiful than female birds Internal fertilization (sperm and egg meet inside the body) Oviparous – the female lays an egg and waits for it to hatch Male birds will court the females (make the girls interested) by singing or looking beautiful, then impressing the female by making a nest (bird home)

Bird Reproduction

Bird Behavior Some birds migrate – they fly to a place that is warmer as the weather grows colder They usually fly south in the fall (September/October) and north in the spring (April/May) Most birds migrate to the same place all their lives