BI 173 - Chapter 30 - Birds.

Characteristics: Most are obviously flight-related.

    Bipedal, w/ forelimbs usually flight-adapted.

    Feet usually w/ four toes.

    Long, flexible neck on rigid body.

    Bony skeleton w/ air spaces.

        Many connected to respiratory system.

        Others in body cavities.

        Modified, keel-like sternum.

    Endothermic, high metabolism.

    4-Chambered Heart. Advanced circulatory system.

    Feathers in thin epidermis. May connect to bones. Insulatory.

    Scales on legs.

    Beak, no teeth.

    Advanced CNS, Digestive Systems. Uric Acid.

    Dioecious, w/ internal fertilization.

        Yolky, calcified eggs.

        Nesting & Care for young. (Precocial vs Altricial)

        Monogamy common.  Usually temporary.

        Sexual selection evolution powerful. Song, coloration, behavior.

    Many migrate - rationale.

        Navigation.

Michael McDarby,
        Based Upon Hickman-Roberts-Larson Biology of Animals,
            1998, WCB McGraw-Hill.
        Internet Version Uploaded 2001.