BIOL 1108 1st EditionFinal Exam Study Guide Lectures: 27-39Lecture 27 (March 23)BirdsI. 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 adaptations1. 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  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 smell Lesson 28 (March 25)Power-Promoting Adaptations I. Power-Promoting Adaptations1. 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 fromo Papilla: cells being produced  Rachis- (shaft) middle part of the feather Vane- portion that has feathers on ito 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 feathero Umbilicuses were sources of nutrients during development - Barbs Central part of the barb is a ramus Barbuleso Proximal barbule- microstructures on the barb that point towards the bodyo 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 wingo 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 insulationII. 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 weighto More surface area to volume ratio for insulation III. 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