class aves. archaeopteryx 150 mya archaeopteryx skeleton
TRANSCRIPT
Class Aves
Archaeopteryx
150 MYA
Archaeopteryx Skeleton
Avian Skeleton
Major Bird Groups
• Paleognathae– Mostly flightless– Usually ratite sternum (flat)
• Neognathae– Mostly flying birds with carinate sternum (keeled)
Is It A Bird?
• Wings• Feathers• Beak• Oviparous
Placode Specification
Placode Growth
Barb & Barbule Development
Down feather development
Pennacous feather development
Mature FeatherPennaceous
Plumulaceous
Feathers or Scales
Inhibition of BMP4 signaling in chick hindlimb causes dorsal scales (scutes) to develop as feathers and prevents apoptosis of interdigit webbing
Does a Chicken have Lips?
Figure 1 A "hen's tooth" formed by the combination of chick pharyngeal (presumptive jaw) ectoderm and mouse molar mesenchyme. (From Kollar and Fisher, 1980; courtesy of E. J. Kollar.)
Adaptations for Flight
Unique Pulmonary Structures
Bird Brained
A Bird's Eye View
Optic nerve
Wing Forms
Migration
Navigation
• Birds can sense Earth’s magnetic field
• Orient relative to field• Calibration of internal
compass– Twilight cues– Nocturnal celestial cues– Daylight cues
Parenting
Juvenile Forms
Reproductive System
Largest Bird
Largest Flying BirdAlbatross – 11ft wing-span
Smallest Flying Bird