Transcript Class Aves: Birds

Class Aves: Birds
18A
Common Characteristics
• Covered with feathers
• Have thin-walled, often hollow bones (these bones are
not lighter, but they are denser, stiffer, and stronger)
• Require enormous amounts of energy
• Demand lots of oxygen for respiration
• Are endothermic (warm-blooded)
• Have high metabolism
• Have no teeth (durable beak made of keratin is just as
efficient but lighter)
• Oviparous
Feathers
Care
• Gland at base of tail produces oil
• Preening- bird applies oil to feathers with its bill while it adjusts and
smoothes its feathers
• Oil provides waterproof shield
Feathers
Function
• Shape the body to make the bird aerodynamic
• Help birds retain heat
• Serves as cushion- protecting the skeleton during collisions
• Help camouflage the bird or attract and identify a mate
Feathers
Structure
• Grow from a structure in the skin called a papilla
• The feather consists of
– Flat vane which consists of parallel rows of thin
barbs with parallel rows of thin barbules that are
hooked together
– Rachis- shaft within the vane
– Quill- hollow shaft from papilla to vane
Feathers
Two types
• Down feathers make up the underlayer providing insulation as and cushion
• Contour feathers are the vaned feathers that cover most of the body and give
external shape and color, and also the flight feathers which extend from the wings
and tail
Feathers
• Fully developed feathers, likes scales and hairs
are dead
• Bird sheds or molts old feathers and replaces
them
Appendages
•
•
•
•
Forelimbs (wings) for flying
Penguins and some other flightless birds use their “wings” to swim
Lower part of the hind limbs are usually thin and covered with scales
Most birds have 3 or 4 clawed toes
Wings
• Elliptical- short and wide providing for quick takeoffs and landings,
low speed flight, and maneuverability (sparrows, woodpeckers)
• High-speed- thin, long, tapered shape that produces minimum
drag (terns, swifts, sandpipers)
• Soaring- long and thin and resemble the wings of a glider; enable
the bird to expend minimal energy in staying aloft but provide
little maneuverability (gulls)
• High-lift- wings are large and convex; they give a great amount of
lift even at low speeds, allowing birds to carry large prey (hawks,
eagles, owls)
Feet
• Wading- long, thin, widely spread toes that distribute weight;
thin toes and legs permit movement in water without
creating turbulence
• Swimming- webbed and serve as paddles
• Climbing- two toes in front and two behind to provide grip
and balance
• Running- toes are strong and hoof like and support heavy
birds as they run along the ground
• Grasping- toes with talons (long curved claws) designed to
grasp and kill prey
• Perching- three front toes and one back toe; a locking device
closes toes and remains tightly closed until the bird releases it
Skeleton
• A bird’s skeleton has numerous air-filled cavities within the bone
• Elongated upper jaw (maxilla) and lower jaw (mandible) are elongated and form
the bill
• Vertebrae of the tail are free moving and help in guiding flight
• The trunk vertebrae, the flat ribs, and the sternum (breastbone) are fused to make
the trunk a rigid framework
• central ridge of the breastbone called the keel provides attachment for flight
muscles.
• Clavicles (collarbones) are enlarge and fused, forming the “wishbone” which also
provides attachment for flight muscles
Bird Systems
Digestion
• Birds need a lot of energy to fly so they have
to eat a lot.
• They also have to be able to digest food
quickly. They can’t carry heavy food around
while flying and they need the energy.
• The type of bill
depends on the bird’s
diet
• Spearing fish- long
slender
• Probing for insectslong slender
• Cracking and crushing
seeds- short and stout
• Tearing prey- hooked
pointed bills
• Filtering- bills contain
throat pouch
Bill
Digestion
• Esophagus
• Crop- stores food. It is an
enlargement of the esophagus
• Proventriculus- first part of the
stomach, produces digestive juices
• Gizzard- second part of the
stomach, where grinding of the
food (mechanical digestion) occurs.
It has thick muscular walls. Birds
swallow gravel to help grind the
food.
• Intestines- final digestion and
absorption
• Cloaca- serves as the common
opening for the intestine, kidney
duct, and reproductive organs
Respiration
• Air Sacs- unique to birds
– The lungs are unable to supply all the oxygen the bird needs
to maintain its high metabolism.
– As the bird exhales oxygen rich air goes from the air sacs to
the lungs, so the bird has oxygen rich air passing through
their lungs as they breathe in and out.
– Also make the bird light because they are located in places
where fluids or fat would be in other organisms.
Respiration
• High metabolism produces a lot of heat
• Respiration is important because it helps cool
the bird
• They can rapidly move air in and of their air
sacs. The exiting air carries heat.
Circulation
• 4 chambered heart
• Oxygenated and deoxygenated blood completely
separated
Circulation
• Relative to its body size birds have the largest hearts of
all vertebrates
• 135-570 heart beats per minute (avg human heartrate
is 60-100 bpm, could be around 200 bpm during
exercise)
Excretion
• Pair of dorsal kidneys
• Waste empties directly from the kidneys into the
cloaca
• Birds do not store urine or feces
Sound
• Syrinx- song box, enlargement of the trachea
just above where it divides to enter the lungs
• Syrinx and associated muscles produce sound
Bird Mimicry
http://www.youtube.com/watch?v=VjE0Kdfos4Y
Sensing
• Reptiles, amphibians, and fish rely heavily on smell and
taste
• Birds rely heavily on hearing and sight
• Vision of a hawk is 8 times more acute than that of a
human
• Owls can see in light 1/10 to 1/100 the brightness
required by man to see
• Light receptors in the retina of a bird’s eye are packed
from 2-5 times more tightly than those in humans
Falcon
http://www.youtube.com/watch?v=r7lglchYNew
Eagle goat
http://www.youtube.com/watch?v=VklTs-Tid_I
Hawk- iguana
http://www.youtube.com/watch?v=9vQuqg5hZYM
Bird of Prey- Snake
http://www.youtube.com/watch?v=s-sHY1zSA2I
Bird of Prey- Seal
http://www.youtube.com/watch?v=Ugxq3yLNk6g
Bird Orders
http://www.allaboutbirds.org/guide/search
Behaviors
• Mating rituals
Birds of Paradise mating dance
http://www.youtube.com/watch?v=L54bxmZy_NE
Prairie Chicken mating dance
http://www.youtube.com/watch?v=s2_wdMmEupQ