1. Tiara Jackson Shayna Brown AP Biology 4/8/11
Chordates: Birds
Tiara Jackson 
Shayna Brown 
AP Biology 
4/8/11

2. The Name of Your Subgroup
Kingdom: Animalia
Phylum: Chordata
Class: Aves

3. Body Structure
External Bird Anatomy
Internal Bird Anatomy

4. Type of Covering Contour Feathers Down Feathers
Contour, or vaned, feathers are the most specialized of all feathers. Contour feathers form the outline of the body of a bird, giving it a streamlined look. 
Down Feathers
The down of birds is a layer of fine feathers found under the tougher exterior feathers. 

5. Gas Exchange
The avian ventilation/respiratory system, like the mammalian respiratory system, delivers oxygen from the air to the body tissues and it also removes carbon dioxide. But that is where the similarity ends. The avian respiratory system also plays an important role in thermoregulation in that it helps to maintain normal body temperatures despite wide fluctuations in the temperature of the surrounding air.

6. The Heart
Birds have a four-chambered heart, in common with humans, most mammals, and some reptiles. This adaptation allows for an efficient nutrient and oxygen transport throughout the body, providing birds with energy to fly and maintain high levels of activity. A Ruby-throated Hummingbird's heart beats up to 1200 times per minute (about 20 beats per second).

7. Mode of Fertilization and Development
When birds mate, the male presses his sexual opening against that of the female by mounting her and flapping his wings to maintain his balance. Some bird species, such as swallows and swifts, mate while suspended in midair. The male's sperm enters the female's sexual opening (cloaca) during this time.
After entering the cloaca of the female, the sperm, containing the male's genetic information, travels up the oviduct. At the end of the oviduct is an ovum, or egg, which contains the female's genetic information. Fertilization takes place when the male's sperm penetrates the egg, causing the genetic information of both parents to fuse. Fertilization does not necessarily take place during or soon after mating. Some bird species release fertilized eggs up to 70 days after mating takes place.
Development
Once fertilized, the egg begins traveling through the oviduct. As it travels, coatings and membranes are added to it, forming a shell. Once the shell is formed, the egg is ready to be laid and incubated until ready to hatch.
* Internal fertilization and External development 

8. Classification Type of Covering Order: Psittaciformes (parrots)
Kingdom: Animalia
Phylum: Chordata
Class: Aves The Class Aves contains the following subgroups:
Order: Anseriformes (ducks, geese, screame s, swans, and waterfowl)
Order: Apodiformes (hummingbirds and swifts)
Order: Apterygiformes (kiwis)
Order: Caprimulgiformes (nightbirds)
Order: Casuariiformes (emus, cassowaires)
Order: Charadriiformes (shorebirds and relatives)
Order: Psittaciformes (parrots)
Order: Rheiformes (rheas)
Order: Sphenisciformes (penguin)
Order: Strigiformes (owls)
Order: Struthioniformes (kiwis, ostriches)
Order: Tinamiformes (tinamous)
Order: Trogoniformes (trogons)
Order: Turniciformes (buttonquail)
Type of Covering

9. Characteristics
Birds possess distinct characteristics that make them one of the most distinguishable group of vertebrates. The following characteristics are unique to birds:
·                  feathers - provide insulation and enable flight; feathers are modifications of a                 bird's epidermis (outer skin)
·                  bills - birds do not possess teeth or the heavy jawbones seen in other                             vertebrates; instead, birds have a pair of toothless mandibles covered with a                 horny sheath of keratin (also called ramphotheca).
·                  furcula - also known as the 'wishbone', the furcula is a bone located in the                      bird's chest that prevents compression of the chest cavity during the                              downstroke of a wingbeat.
Birds also exhibit the following characteristics:
·                  Fused bones in pelvis, feet, hands, and head
·                  Lightweight bones (bones that are either hollow or spongy/strutted)
·                  No teeth or maxillary bones of the jaw (reduces anterior weight)
·                  Endothermic
·                  Possess a four-chambered heart and in general exhibit high metabolic rates
·                  Produce large, richly provisioned external eggs
·                  Adept navigational abilities in many species 
                   Endothermic
                   Extraordinary communication and song production

10. Works Cited http://biology.clc.uc.edu/courses/bio106/chordate.htm