Class Aves Birds are reptile like animals that

Class Aves Birds are reptile like animals that maintain a constant internal body temperature. They have an outer covering of feathers, 2 legs that are covered with scales and front limbs modified into wings.

Characteristic that separates birds from other animals = feathers Most paleontologists think that birds evolved from extinct reptiles like dinosaurs. Part of the evidence: Archaeopteryx: First birdlike fossil discovered

Well developed feathers like a modern bird. Teeth, bony tail, Toes and claws on its wings like dinosaurs.

Body temperature control: Endotherms - ‘warm blooded’ – they control their Internal body temperature. Feathers help to insulate the body. Most birds internal temperature is about 41 C (105. 8 F) even on cold days. Down – trap air to keep bird warm Contour – provide lifting, force and balance needed for flight

Feeding: Bird’s beaks or bills are adapted to the type of food they eat. Insect eating – fine, short beaks Seed eating – short, thick beaks Long, thin beaks – gather nectar Carnivores – strong, hooked beaks

No teeth – have specialized structures to help break down food. 1. Crop – food is stored and moistened. 2. Gizzard – In birds that eat insects and birds, help further digestion by grinding it. Usually small stones inside.

Respiration: Inhales – most of air first enters large air sacs in the body cavity and bones and then flows to the lungs. Air travels through the lungs in a series of small tubes where gas exchange takes place.

Circulation: 4 Chambered heart. Heart beats quickly – from 150 to more than 1000 beats per minute!

Excretion: Nitrogenous wastes are removed by the kidneys and converted into uric acid. Most water is reabsorbed and excretion is in a white pasty form (bird droppings) Response: Well developed brain that can interpret and respond to A lot of incoming signals. Well developed eyes – can see color well.

Movement: Flight less birds – walk, run Cassowary

Most other birds fly. Adaptations for flight: • Long bones are very strong (strengthened by internal struts) and light (air spaces) • Large chest muscles • Enlarged breast bone or sternum where muscles are attached to. • Feathers

Reproduction: / http: //video. nationalgeographic. com/video/animals/birds-animals/ground-birds/weirdest-bowerbird Internal fertilization Lay eggs – oviparous Eggs have hard outer shells. Most birds incubate their eggs until they hatch. Both parents often provide food for their young.