BIOL108 Lecture Notes - Lecture 33: Pennaceous Feather, Amniote, Archaeopteryx

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Scales - homologous with feathers feathers, hairs, scales share the same developmental & evolutionary origin. Hollow thin-walled bones & 20+ other skeletal similarities. Musculature, brain, heart, and other organs similar. Origin of birds likely have evolved from theropods- small, fast dinosaurs. New fossils: evidence of dinosaurs with feathers. Archaeopteryx: shared a common ancestor with modern birds (transitional organism) But also had teeth, bony tail, claws (that are not present in modern birds) feathers, wings - capable of flight. Aves (birds) & crocodilians are the extant groups of archosaurs. Characteristics of modern birds four-chambered heart (also seen in theropods & mammals) Endothermic (which is similar to carnivorous theropods) Use metabolic energy to maintain body temperature. High rate of metabolism feather & layer of fat help retain body heat. Derived characters - adaptations for flight feathers - key synapomorphy. Birds care for their feathers by preening finely subdivided keratinous scales. Moves oil from gland at base of tail to rest of feathers.