Features of
the Birds
The Origin of Birds
Analysis of birds and of reptilian fossils indicate that birds belong to the group called therapods. Several species of dinosaurs closely related to birds had feathers with vanes, and a wider range of species had filamentous feathers. Such findings imply that feathers evolved long before powered flight. Among the possible functions of these early feathers were insulation, camouflage, and courtship display.
Derived Characteristics of Birds
Many of the characteristics of birds are adaptations that facilitate flight, including weight-saving modifications that make flying more efficient. For example, birds lack a urinary bladder, and the females of most species have only one ovary. Living birds are also toothless, an adaptation that trims the weight of the head....
The Origin of Birds
Analysis of birds and of reptilian fossils indicate that birds belong to the group called therapods. Several species of dinosaurs closely related to birds had feathers with vanes, and a wider range of species had filamentous feathers. Such findings imply that feathers evolved long before powered flight. Among the possible functions of these early feathers were insulation, camouflage, and courtship display.
Derived Characteristics of Birds
Many of the characteristics of birds are adaptations that facilitate flight, including weight-saving modifications that make flying more efficient. For example, birds lack a urinary bladder, and the females of most species have only one ovary. Living birds are also toothless, an adaptation that trims the weight of the head....