BIOL 1108 1st Edition Final Exam Study Guide Lectures 27 39 Lecture 27 March 23 Birds I Bird 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 mass o Ex Synsacrum fusion of the pelvic girdle and vertebral column o 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 Flexible 3 Lack of skin glands Uropygial gland or preening gland o Located at the base of the tail o Secretion waterproofs the feathers 4 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 Turkey 7 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 smell Lesson 28 March 25 Power Promoting Adaptations I Power Promoting Adaptations 1 Endothermy allow high metabolic rates to sustain a power flight Q10 Effect Birds have the highest body temperature of all vertebrates 104 degrees F 40 degrees C Feathers evolved into fur a form of insulation 2 Specialized Flight Muscles Pectoralis down stroke Supracoracoideus up stroke Together these muscles make up to 35 of body weight Keeled sternum provided extra surface area for muscle attachment Flightless birds do not have a keeled sternums Carinate sternum flying birds Ratite sternum flightless birds 3 Circulatory System white meat breast less myoglobin dark meat leg more myoglobin Color depends on amount of myoglobin oxygen binding protein in muscles 4 chambered heart double circulated Birds have the largest heart to body mass ratio Hear rate decreases as body size increases negative relationship Steeper range 4 Respiratory System 20 of body volume 2 lungs 18 air sacs Air Sacs compliment the respiratory system Usually 9 varies from 6 12 No gas exchange in the air sacs just lungs 2 functions 1 Increase oxygen utilization by allowing a one way movement of air takes 2 respiratory cycles one way movement of air more efficient 2 Cooling system moisture surfaces provide evaporative cooling as air is moving in and out of body prevents overheating 5 Aerodynamics and Balance Center of balance is just under the wings Organ placement on both sides for balance 6 Feathers Development Follicle indentation in the skin that the feather grows from o Papilla cells being produced Rachis shaft middle part of the feather Vane portion that has feathers on it o Attached by barbs which contain microstructures Calamus below the vane down to the base of the feather hollow Superior umbilicus hole on top of calamus Inferior umbilicus hole at the end tip of the feather o Umbilicuses were sources of nutrients during development Barbs Central part of the barb is a ramus Barbules o Proximal barbule microstructures on the barb that point towards the body o Distal barbule point away from body Barbicells attached to barbules Hamuli hooklets on distal barbules only Lesson 29 March 27 Bird Feathers I Feather Types 1 Contour Feathers Form the outline of the body Large vane Flight feathers o Remiges flight feathers of the wing o Rectrices tail feathers Pterylae feather tracts where contour feathers grow Apteria areas between feather tracts 2 Semiplumes Loose vane feather Lacks hooklets hamuli Grow at the margins edges of the feather tracks Functions o Insulation by trapping air o Providing flexibility o Buoyancy for some birds 3 Filoplumes Hair like feathers that lack a vane or have a much smaller one Extend the contour feathers 4 Bristles Occur around the mouth nostrils or eyes Vaneless Rictal bristles enlarges bristles around the mouth 5 Down downy Small soft feathers that lack a vane For insulation Overlaying contour levels Not confined to the pterylae 6 Powder Down Powder functions to waterproof feathers Ends of feather disintegrate into a powder Only type that can grow continuously throughout life 7 Aftershaft Accessory feather Grows at the base of another feather Correlation of temperature and occurrence of aftershaft Provides extra insulation II III Number of Feathers Ruby throated Hummingbird 940 feathers Whisling Swan 25 216 feathers The bigger the bird the more feather it has Feathers gram of body weight o Smaller birds have more feathers per weight o More surface area to volume ratio for insulation Plumage and Molts Plumage entire feather covering of a bird Molt sequence of feather replacement o Certain feathers fall out at certain times of the year o Temporal sequence Natal Down first plumage Altricial hatch with only a few down feathers mostly bare skin not capable of coordinating movement or maintaining temperature Nidicolous nest inhabitant stay in the nest after hatching Precocial hatch with a complete down covering little bare skin can coordinate movements and maintain temperature Ex Ground nesting birds acceptable to predation Nidifugous nest fugitive leave nest soon after hatching Juvenal Plumage starts looking like adults less down o Partial Molt only contour feathers in certain pterylae are replaced not the flight feathers o Complete Molt all feathers including flight feathers are replaced Lesson 30 March 30 Molt of Feathers I Molt Partial Complete o Sequential molt flight feathers replaced in sequence o Simultaneous molt flight feathers are replaced all at once short flightless period Humphrey and Parks 1959 o Songbird pair bonds at breeding grounds Date May June Aug Feb Aug Feb Event Hatch molt molt molt molt molt Molt N A prejuvenal 1st prebasic 1st prealternate