Flashcards in Bird Anatomy Deck (176):
What do most of the internal adaptions of a bird's body help it to do?
What are the main adaptions that permit flighted birds to fly?
Light skeletal system, light but powerful muscles, and circulatory/respiratory systems capable of very high metabolic rates.
The development of what caused birds to have a very special digestive system?
What is ossification (osteogenesis)?
The process of laying down new bone tissue by cells called osteoblasts.
What are some theories as to how bones came to be in organisms?
It developed from tissues designed to store minerals. (cartilage stored the minerals and bones evolved from this newly-calcified tissue) Other theories include it coming to be because of osmotic protection or a protective structure.
What adaption has caused birds to have less bones and lighter skeletons than most vertebrates?
Many of their bones have fused together into single ossifications.
What is a pygostyle?
The final few bones in a bird's body supporting the tail feathers.
Why did modern birds evolve to have a pygostyle?
It allows for much easier flight control.
What is a uropygial gland and where is it located?
The uropygial gland is located beneath the pygostyle and produces preen oil.
When did pygostyles first start appearing in birds?
In the Cretaceous period. (Around 140 million years ago)
True or false? Archaeopteryx was likely a poor flyer because it had a full tail rather than a simple, lightweight tail feather supported by the pygostyle.
What is the use o the pygostyle in birds that cannot fly?
To engage in courtship displays.
Why do birds have beaks and not teeth?
Beaks are far more lightweight.
Why don't many diving birds have bones that are as hollow as other birds?
It allows them to dive better.
What is the fastest-flighted bird when pumping its wings?
What flightless birds have surprisingly hollow femurs?
Emus and ostriches.
True or false? Birds have less neck vertebrae than most other kinds of animals due to ossification.
False. They have more neck vertebrae than other animals.
Why do birds have specialized collarbones and/or keeled sternums?
It serves as an attachment site for the muscles used for flight or swimming.
What is the keel in regards to bird skeletons?
It is a small extension of the sternum that provides an anchor for the flight muscles.
What kinds of birds lack a keeled sternum?
In the past, what two groups were birds classified into?
Carintae (Birds with a keel) and Ratites (Birds with no keel)
Why did evolutionary scientists get rid of the ratite class?
They discovered that some flightless birds evolved from flighted birds.
What do the sternums in walking birds look like? In flying birds? In swimming birds?
Swimming Birds: Wide sternum.Walking Birds: Long or high.Flying Birds: Equal dimensions.
What are uncinate processes?
They are bony barbs that extend from the ribs.
What are some roles of the uncinate processes?
They attach scapula muscles, help to strengthen the rib cage, and increase the effectiveness of respiration.
What is the length of uncinate processes in walking, diving, and flying birds?
Walking: ShortDiving: LongFlying: Intermediate
What other kids of animals have uncinate processes besides birds?
Reptiles and early amphibians.
What kinds of reptiles exhibit uncinate processes?
The tuatara and crocodiles.
what is unique about the uncinate processes of birds?
They are bony. The uncinate processes of other species are cartilaginous.
How do uncinate processes strengthen the rib cage?
They are hooks that wrap around the rib behind them.
What kinds of skulls do birds and reptiles have?
What is the main characteristic of a diapsid skull?
They have two holes in their temporal bones (one on either side). They may also have other holes.
Why are lizards and snakes still considered members of the diapsid group despite having one or no holes respectively?
They remain there due to their ancestry.
What does the name "diapsid" mean?
What are the holes in the skull of a diapsid called?
What is the occipital condyle?
A bone on the bottom of the skull that attaches the head to the spine and body.
How many bones doe the skull of a bird consist of and what are their names?
Five bones. The frontal (top of head), parietal (back of head), premaxillary and nasal (top beak), and the mandible (bottom beak)
How much of a bird's body weight is taken up by the skull?
How are bird's legs similar to that of a reptile?
They have a special joint known as the intra-tarsal joint.
How are the eyes of birds and reptiles similar?
They both have a circle of tiny bones around their eyes.
The pelvis of a bird is how many bones that have been fused together?
Why is the evolution of the innominate bone in the birds so significant?
It is what has allowed them to lay eggs.
What is the combined fusion of the three pelvis bones of a bird called?
The innominate bone.
Why are the leg bones of a bird the heaviest?
They contribute to a low center of gravity and help the bird in flight.
How much of a bird's body weight is comprised of its skeleton?
What percentage of a human's body weight is comprised of its skeleton?
What is the most common type of foot in birds and what is the configuration of the toes?
Anisodactyl. Three toes in front and one in back.
Barring anisodactyl, what are the other configurations and names of bird feet?
Didactyl (two front toes), tridactyl (three front toes), and zygodactyl (two in front and two in back)
What are zygodactyl toes good for?
Climbing tree trunks or clambering through foliage.
How many muscles do birds have?
What do the muscles of a bird control?
The legs, wings, and skin.
What are the largest muscles in a bird?
The pectoral muscles.
How much of a bird's body weight is made up of the pectoral muscles?
What muscle is responsible for raising a bird's wing between wing beats?
How do skin muscles help a bird?
They adjust the feathers and help birds in their flight maneuvers.
What controls the movement in the tail?
Why do birds have tail feathers?
They give the bird a larger surface area on its tail and allow them to control their flight easier.
Beaks, claws, scales, and spurs are made of....
Where are scales found on birds?
On the feet.
True or false, the scales in birds are exactly the same as the scales of mammals and reptiles.
False. It has been discovered that some birds evolved or changed their scales after the evolution of feathers.
What is homology?
The existence of shared ancestry between a pair of structures, or genes, in different species. For example,
What is convergent evolution (analogous structures)?
Convergent evolution describes the independent evolution of similar features in species of different lineages. For example, birds and bats both have wings, but wings were not present in the last common ancestor of them.
What is a scute?
A bony plate overlaid with horn.
How are scutes different from scales?
Scales grow from the epidermis whereas scutes form in the dermis.
What is an osteoderm?
A scute with a bony base.
What birds have scales that overlap?
Kingfishers and woodpeckers.
What is the corneum?
The outermost layer of the epidermis.
Birds have three types of scales that increase in size. What are they?
Cancella, scutella, and scutes.
What does "caudal" refer to?
The posterior side of something.
What kind of keratin are reptile scales made of?
What is the difference between alpha and beta keratins?
Alpha keratins are found in the hairs, horns, and hooves of mammals and are rich in alpha helices. Beta keratins are found in reptiles, birds, and porcupine quills. they are rich in beta sheets.
What is interesting about some of the scales on the side of a bird's foot?
They lack beta keratins and are almost entirely composed of alpha keratins.
What are Herbst copuscules?
They are special nerve endings that many wading birds have in their lower mandibles to detect minute movements in the water.
What is the region between a bird's eye and bill called?
What is the scaly covering on a bird's foot called?
Why don't ducks feet get cold in the winter?
There are very few veins in the duck's foot and the veins that pump warm blood directly from the heart pass very close to cold blood returning from the foot. The heat is exchanged between the two and acts like an antifreeze. Also, most of the muscles that control the foot are located higher up in the leg and connected to the foot by tendons. Because of this lack of soft tissue, there is less need for warm blood.
What is the thin, keratinized, epidermal layer covering the beak called?
What are the holes in a bird's beak that lead to the respiratory system called?
Why do birds require a lot of oxygen?
They have very high metabolic rates that are required for flight.
What do birds use for most of their respiration?
Air sacs that are attached to their lungs.
What is gas exchange?
A biological process through which different gases are transferred in opposite directions across a specialized respiratory surface.
True or false, bird lungs are smaller than those of mammals.
True. It is the air sacs that are large.
How do air sacs work?
They bellow air through the respiratory system and store extra air.
Does inhalation or exhalation require a muscular contraction in birds?
What is the purpose of respiration?
To oxygenate tissue and get rid of waste products created by metabolic activities.
Since birds lack a diaphragm, what do they expand to draw in air?
The rib cage.
Does oxygenated air enter the birds lungs when it inhales or exhales?
The bird's respiratory system is connected to pneumatic bones. What does this allow it to do?
Remove excess heat from the body as it breathes.
What are the three main parts of the avian respiratory system?
The trachea, the lungs, and the air sacs.
What are the two kinds of air sacs in birds?
The anterior air sacs and the posterior air sacs.
How many air sacs are there in birds?
How many times does a ruby-throated hummingbird's heart beat per second?
What is the maximum amount of times a hummingbird's wings beat per second?
Why do birds have a four chambered heart?
It allows for an efficient nutrient and oxygen transport throughout the body.
Are scutes or scales more closely related to feathers?
What order contains half of all bird species?
How many air sacs do passerines have?
What is the largest order of tetrapods?
What is a tetrapod?
A four-limbed vertebrate.
Where does air enter a bird?
Through the nares.
What is the vocal organ of the bird and where is it located?
The syrinx. It is located at the bottom of the trachea where it separates into the bronchi.
What allows the syrinx to make sounds?
The vibration of the walls and a bar of cartilage. The walls have special membranes that can expand and contract to regulate the sound.
True or false? birds are capable of producing more than one sound at a time.
How can birds produce multiple sounds at once?
The syrinx is located at the base of the trachea and it is split into two pipes. A sound can come from both pipes.
Why do people breed waterschlager canaries?
They produce long and complex songs.
Can birds shut one pipe of their syrinx if they want to?
Why do some species of birds require such precise control over their vocals?
The ability to produce certain sounds in a particular way is a sign of fitness in males. It also allows for rapid changes of notes and syllables.
What are sexy syllables?
Two sounds produced simultaneously from each side of the syrinx that male birds use to attract females.
What happens when a bird changes notes and only uses on of the pipes of the syrinx?
The sound becomes slurred.
True or false? Bird lungs continuously change in volume.
False. Because of air sacs, bird lungs maintain a fixed volume.
Where does air go after it goes down the trachea and past the syrinx of a bird?
Into the primary bronchi. (Also called the mesobronchi)
Where do the mesobronchi deliver the air in a bird?
The posterior air sacs.
What is dead space?
Air that is inhaled, but does not take place in gas exchange.
What is a bronchus?
A passage through which air is delivered.
What is the trachea of a bird usually filled with?
Birds have the most efficient respiratory system of any land animal, but some fish have a more effective respiratory system. What is it called?
The counter-current respiratory system.
What is the muscular pouch in a bird's esophagus that stores food called?
The gizzard is four muscular bands in the bird's throat. What is the purpose of the gizzard?
To rotate and crush food.
Why do some birds swallow pebbles or grit?
To aid in the grinding process of their food.
True or false? A large similarity between birds and dinosaurs is that dinosaurs also swallowed rocks to help digest their food.
What are the four ways in which birds drink?
Using gravity, sucking, use of the tongue, and deriving water entirely from food.
What allows seabirds to drink salt water?
Special glands near their eyes.
Where do seabirds expel excess salt from?
Why can't most kinds of birds simply swallow things like humans?
They do not have the ability to use peristalsis.
What are the four steps of the avian respiratory system?
1st Inhalation: Breath travels down the trachea, through the parabronchi, and into the posterior air sacs.1st Exhalation: The air is forced from the posterior sacs and into the lungs. Gas exchange happens.2nd Inhalation: The air is forced from the lungs and into anterior air sacs.2nd Exhalation: The anterior air sacs contract, forcing the air up the trachea.
How many songs does the red-eyed vireo sing every day?
How fast do pileated woodpeckers hammer on trees?
15 beats a second
Why do birds sing?
To impress mates and claim territories..
How much of the day will dickcissels spend singing?
How many different songs can the brown thrasher sing?
Why do male birds sing more often than females?
Male birds are often the ones who do the courting and establishing of territories.
True or false? Some tropical birds will engage in complex duets between the male and female or even multiple males.
Do male birds that sing more often or less often get more mates?
What two habitats contain many birds that sing while in flight?
Tundra and grasslands.
What bird will fly several hundred feet into the air to sing so that he can be assured that males from miles around can hear him?
The purple martin.
True or false? A woodpecker's drumming serves different purposes than singing.
False. It is used to establish territory and gain mates.
How do woodpeckers amplify their drumming?
They purposely select hollow branches and trees.
How will the male ruffed grouse attract a mate?
He will stand tall, cup his wings, and bring them up and forward with such force that it will make loud, low-frequency booms. He will begin slow but eventually go to a speed so fast that it sounds like a lawnmower.
Why do birds call?
Interacting with the flock or family, alerting each other to danger, or sharing information about food.
What are contact calls?
Calls that birds use simply to keep in touch.
How do avian mates identify or find each other in large flocks?
They can mimic each other's contact calls.
What is the vocalization that birds leading a flock will use to make sure their flock is following them at night?
Nocturnal flight calls.
What is an alarm call?
A call that a bird will use to alert other birds of a threat.
True or false? Che chickadee's alarm call is the signature chickadee-dee-dee call.
What do some people believe determines the chickadee's perceived threat level?
The number of "dees" in its call.
How do alarm calls help to discourage predators?
They let the predator know that they have been spotted. They can also allow flocks of birds to mob the predator.
Why will birds vocalize to attract other birds when they find food?
By having a large flock around, they increase the chance that they will continue to find food, especially with mobile groups of insects.
What kind of call do young birds make to let their parents know they're hungry?
True or false? all species of birds learn to sing in similar ways.
How do flycatchers learn to sing?
They are born knowing the songs in their genetic code.
How do songbirds learn to sing?
They listen to and mimic other birds of their kind.
What happens when a white crowned sparrow is raised by a song sparrow?
It sings the song of a song sparrow.
What happens when a white crowned sparrow is raised without other birds around?
It develops an odd song.
Do all songbirds sing?
No. Crows are an example.
What can cause differences in how many songs a bird can sing?
Geographic location, lifestyle, or age.
What are some theories as to why some birds use mimicry?
Females prefer males with more songs, to keep more species away from their territories, so that parasites will not be recognized as intruders in a host bird's nest, and to ward off predators from their nest.
How does a hummingbird drink?
The tongue is shaped like a trough, so they can scoop nectar and water with it.
How many times larger do the testes of a bird become in the breeding season.
Do most birds have a penis?
How do birds mate?
They simply touch cloacas.
When are bird eggs fertilized?
As they leave the ovaries.
Where do female birds store sperm prior to fertilization of the egg?
In a small internal structure.
Where is the shell of the bird's egg calcified?
In the oviduct.
True or false? After an egg is laid, the infant continues to develop outside the female body.
What male birds do have a penis?
Ostrich, turkey, and most famously ducks.
Why is it thought that some species of birds kept the penis?
In species that mate multiple times, sperm delivered closer to the ovaries is more likely to achieve fertilization.
Where is the penis of a bird hidden when not mating?
Inside the cloaca.
What is a precocial bird?
A bird that is relatively mature and mobile when hatching.
What is a nidifugous bird?
A bird that can run almost immediately after hatching. Examples include partridge and waders.
What is the process by which a chick acquires feathers until it can fly?
How do desert birds reduce their demand for water?
They will excrete many of their nitrogenous wastes as uric acid.
What is the white stuff in bird poop?
How many times sharper is the eyesight of a raptor than a human's?
Why is the eyesight of raptors so good?
More photoreceptors in the retina, more neurons in the optic nerve, a unique set of second eye muscles, and a small indent in the fovea region of their retina that magnifies the central part of their visual field.
True or false? Birds can detect polarized light.