1. Birds

2. Characteristics Forelimbs  wings Feathers (of beta keratin, same protein in scales of legs) Flight requires lots of energy – Features that reduce weight – Features that increase energy production – Adaptations for flight: No urinary bladder Single ovary Reduced gonads Skeletal modifications One-way respiratory system (w/ parabronchii) 4 chambered heart (evolved independently of mammal heart) endothermic

3. Benefits of flight Increased foraging ability Massive migrations to seasonal food sources Feeding on airborne insects (new food resource) Dispersal Escape from predators

5. Keel of sternum (#4) Furcula (wishbone/collarbone) # 5

7. Flightless Birds Ratites – lack sternal keel – pectoral muscles are reduced/small – Ostrich (Africa) – Rhea (south America) – Kiwi (new Zealand) – Cassowary (Australia & new guinea and surrounding is.) – Emu (Australia and Tasmania) Penguins are flightless But have keel and powerful pectoral muscles because they use wings to “swim” under water.

9. Respiratory System No diaphragm Air sacs act as bellows One-way air flow through lungs Parabronchi No mixing of residual and fresh air Counter current like gas exchange

13. Vocalize w/ Syrinx (not larynx) Schematic drawing of an avian syrinx 1: last free cartilaginous tracheal ring, 2:tympanum, 3: first group of syringeal rings, 4:pessulus, 5: membrana tympaniformis lateralis, 6: membrana tympaniformis medialis, 7: second group of syringeal rings, 8: main bronchus, 9: bronchial cartilagetracheal ringtympanumpessulusmain bronchus membrana tympaniformis

15. Digestive System No teeth CROP—stores food Proventriculus—released digestive enzymes Gizzard (ventriculus)—mixing and mechanical digestion

16. EXCRETORY SYSTEM Kidneys produce uric acid No urinary bladder Ureters connect to digestive track just upstream of cloaca Bird “poop” is a mix of feces and uric acid (white stuff) They don’t hold it (much) it comes out on demand

17. Nervous System Flight requires well developed nervous system Vision – Complex eyes – Large orbit of skull Disproportionately large brain – Processing visual information – Integrating sensory and motor function for flight – Intelligent! – Complex behaviors

18. Reproduction Internal fertilization – Cloacal contact (kiss) Eggs/oviparous – Adaptation for flight Often biparental care Most birds are monogamous (with lots of cheating) – Because off spring require so much care—takes both parents – Incubating – Feeding young (young have high energy demand so need lots of food) – Protecting young