What to know?What are the functions of feathers? Insulation, flight, ornamental/sexual signalingMuscle fiber/metabolic differences (depending on biology of the bird, where would you expect to find muscles with a lot of myoglobin?) -Flight muscles account for 25-35% of the total body mass of strong fliers-Predatory birds, limb muscles 10% (flight muscles ~20%)-Swimming birds, even distribution of limb and flight muscles-Muscle fiber types and metabolic pathwaysDark Meat: legs; high capacity for aerobic metabolism; myoglobinWhite Meat: wings; little capacity for aerobic metabolismStrong fliers: breast muscles with high aerobic metabolic capacitiesWhich wing feathers (specifically) are responsible for flight?The feathers responsible for flight in a bird are the inner remiges often referred to as secondaries (ulna- help lift). They are attached to the 'forearm' of the bird and are located between the body of the bird and the primaries (handbone- help propel).-_M_a_j_o_r_ _m_u_s_c_l_e_s_ _i_n_v_o_l_v_e_d_ _w_i_t_h_ _f_l_i_g_h_t_1_)_ _P_e_c_t_o_r_a_l_i_s_ _m_a_j_o_r_ _–p_u_l_l_s_ _w_i_n_g_ _d_o_w_n_2_)_ _S_u_p_r_a_c_o_r_a_c_o_i_d_e_u_s_ _–l_i_f_t_s_ _w_i_n_g_In general, how do birds fly?When a bird flaps its wings, air is pushed downward. This produces an opposite force that “lifts” the bird into the air. Since a bird’s wing is in the shape of an airfoil, it produces some lift even when the bird is just gliding.Alula – extra little wing on top of hand helps air flow smoothly overPrimaries – big long wing feathers Secondaries – feathers on arms-primaries propel, secondaries liftdrag – force that is oppose to forward motion & wing movementair pressures can differ on dorsal & ventral side of wingangle of attack will help prodice lift -angleWing loading – body mass.wing span area – if too heavy & wings 2 small don’t flyAspect ratios – length:widthLift: vertical force equal to or greater than weight of birdWing proportions/types of wingsBird can kinda change surface are by changing feather posish but mostly evolutionary.Depending on if bird is a flier, or soaring gives birds lengthened arm sections. – hummingbird has fast wing beats which needs max force from primaries so their hand bones are longer than both forearm +upper arm. Barely have secondariesDiving – needs high aspect ratio – fast strong fliers – slender top, no wing slots, arms bent backElliptical – rapid or slow flight w/ high maneuv. – low asp. Ratio equalish – broad and square/elliptiicalDynamic – soaring – long flat narrow wings, needs persistent wind High lift – static soarers maker slotting in primaries seek out rising air masses. Intermediate aspect ratio –light wing loading & maneuv. Broad wings & high slotting gives maneuv. To changes in wind curents by changing positions of individual feathers vs moving whole wingUnderstand respiratory and circulatory system of birds-Separate systemic and pulmonary sides of the heart- Division via a permanent septum; between ventricles; this is lacking in turtles, lizards and they therefore have lower blood pressure and rates of blood flow- The permanent ventricle allows higher rates of flow associated with higher overall metabolism in birdsHeart – entire left systemic arch is lost & sinus venosus has been subsumed into the right atriumInspiration – Ventral rotation of the sternum while the longissimus dorsi muscle pulls on the ileum & lifts the pelvis; both of these movements increase thorax volumeExpiration – sternum returns to resting position & contraction of the suprapubic & infrapubic abdominal msucles pulls the pelvis downward reducing the volume of the thorax.2 groups of air sacs anterior & posterior occupy much of body and are poorly vascularized, do not participate in gas exchange but are very large and used as reservoirs that store air during parts of the resp. cycle to create a through-flow lung where air flows only 1 directionHave Cervical abdominal interclavicular, anterior & posterior thoracic air sacs connected to lungs by ventro/dorsobronchi1stinhalation: trachea, posterior air sacs1stexhalation: posterior air sacs, lungs2ndinhalation: lungs, anterior air sacs2ndexhalation: anterior air sacs, trachea, outUnderstand how and why endothermy evolved in birdsIssues – Need to resolve conflict b/w locomotion & lung ventilation that results from the primitive tetrapod method of locomotion. - > derived upright posture was developed w/ bipedality & primitive pattern of hindmuscles was retainedNeed more oxygen to support the high metabolic rates associated w/ locomotion (flow through lung)Need more food to fuel high metabolism - Gizzard-Air exchange and sustained locomotion/activity produces heat and a substantial amount of energy lost as heat-Body forms and posture changes to better deal with increased activityTemperature regulation via ectothermy or endothermyFor endothermy to evolve, need insulation and high metabolic rate-Feathers –insulation, but can be moved to enhance air flow across the body to facilitate coolingWhat are the different types of bird feet, beaks, and tongues covered in lecture?Wood pecker tongues- elongated hyoid bone supporting the tongue inside a sheath of muscle that oases around the outside of the skull and rests in the nasal cavity. When contracted, the tongue is pushed out of the mouth. The tip of the tongue has barbs that impale insects to pull them out of tunnels.No teeth, gastric apparatus helps process food that would normally occur in the mouthCrop –enlarged portion of the esophagusStomach –Proventriculus and gizzardProventriculus –chemical digestionGizzard –food storage, mechanical processing of foodSmall IntestineLarge Intestine Ceca –at junction of small and large intestinesCloaca –stores waste temporarily Wastes –uric acidA) Anisodactyl –hallux behind the other 3 toes (thrushes)B) Zygodactyl –toes in pairs, 2 and 3 forward (parrots and woodpeckers)C) Heterodactyl –like zygodactyl, but toes 3 and 4 forward (only in trogons)D) Syndactyl –toes 3 and 4 united, broad sole (belted kingfisher)E) Pamprodactyl all toes forward (swifts)What are the main functions of hind feet? -Perching (anisodactyl foot -all 4 toes are free and mobile and of moderate length common in passerine birds; zygodactylous foot –perch/climb on vertical services and common in parrots and woodpeckers)-Hopping, walking and running-Climbing -Surface swimming (palmate, totipalmate, lobes)-Diving