WILD 3580 1st Edition Lecture 27Outline of Last Lecture I. Behavioral ThermoregulationII. LocomotionOutline of Current Lecture I. Bird EvolutionII. Characteristics III. Weight reducing adaptationsCurrent LectureI. Birds Evolution- Evolved from theropod dinosaurs o Archaeopteryx first recorded bird o Tendency toward bipedalism- Uncertainty of bird class in relation to reptiles II. Characteristics - Related to flight 1. Low weight relative to size 2. High Power 3. Aerodynamic Shape III. Weight reducing adaptations 1. Skeletal characteristics Light weight Pneumatic bones- thin walled and hollow Fusion and loss of bones- adds strength without extra masso Ex. Synsacrum: fusion of the pelvic girdle and vertebral columno Ex. Furculum: “wish bone”, fusion of the clavicles o Ex. Carpometacarpus: fusion of the distal bones in the wing Elastic 2. Feathers Strong relative to weight Made of beta-keratin These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Flexible 3. Lack of skin glands Uropygial gland or preening gland o Located at the base of the tail o Secretion waterproofs the feathers4. Excretory System Lack of urinary bladder Uric acid form- little water, high concentration of wastes 5. Reproductive System Most birds of a single, left ovary and oviduct All birds are oviparous- lay eggs Breeding seasons are short and well-defined Recrudescence: the enlargement of the gonads during the breeding season; only become functional during this time (regression)6. Digestion System Consume highly digestible and high calorie foods Seeds, fruits, insects, other vertebrates Digestion is short and efficient o Exceptions: Herbivorous species- eat plants, usually remain on the ground; need less energy - Ex. Grouse and Turkey7. Nervous System Weight reduction has not occurred at the expense of the brain Cerebellum and cerebrum are large o Coordination centers Large optic lobes- see better to fly and land, increase mobility in the neck due to lack of eye muscles Anosmic- reduced sense of
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