Stone Lab Birds Flashcards
What is a bird?
A bipedal, tetrapods, vertebrate
What characteristics make a bird unique?
Feathers, bills, pneumatic skeleton, furcula, avian air sacs, eye anatomy, and syrinx.
Why are feathers important to a bird?
Birds use feathers for flight, communication, thermoregulation, and camouflage.
What is the structure of a bird’s bill?
Bill is bone with keratin on top. The bone has trabeculae (bony struts). Bills lack teeth.
How do birds use their bills?
Birds use bills for finding food, cleaning themselves, making nests, and caring for young. The bill also helps the bird release body heat.
How do birds break down their food without teeth?
The gizzard is a muscular organ that “does the chewing for the birds.” Birds will add grit or stones to help with process.
What is the structure of the pneumatic skeleton?
The bone is a thin covering supported by struts the create hollow cells within. This makes the bone strong and lightweight.
What is a furcula?
The clavicles of the bird are fused together to form “wishbone” structure.
Why is a furcula helpful to a bird?
The furcula acts like a spring to assist the bird in its wing upstroke.
How does a bird breath?
When the bird inhales, air goes to the posterior air sac. The first exhale moves air into the lungs. The second breath in sends air to the anterior air sac. The second exhale sends mostly carbon dioxide out of the bird.
Why is the use of air sacs beneficial to the bird?
It allows the bird to maximize the usage of oxygen from each breath.
What is unique about a bird’s eye anatomy?
The bird has unique cones that allow it to see colors that humans cannot detect. Birds can also see into the UV range of EM spectrum. Birds eyes also contain the pectin; although, its function is not fully known.
What is the syrinx?
The organ that makes bird songs and calls. It works together with air sacs. This organ is lacking in some birds.
Why is Archeopteryx considered a transitional fossil?
It has characteristics of reptiles and birds.
What characteristics of Archeopteryx are like birds?
The shoulder girdle, the pelvic girdle, the paired clavicles to form furcula, and anisodactyl foot.
What characteristics of Archeopteryx were like reptiles?
It had teeth, a long tail with vertebrae, claws on all its digits, and no keel.
Why do scientists believe Archeopteryx could fly?
It had an asymmetrical feather.
What are the two competing theories about the evolutionary origin of birds?
Thecodant theory has birds and dinosaurs sharing a common ancestor. Theropod theory has birds evolving from theropod dinosaurs.
Which theory of bird evolutionary origin is more widely accepted?
The theropod theory is more widely accepted because it is most parsimonious.
What are the two theories about the origin of flight in birds?
Arboreal theory suggests bird ancestors developed flight to glide between trees. Cursorial theory suggests bird ancestors developed flight to extend jumping while running.
What are common characteristics between birds and reptiles that suggest they are related?
Sclerotic eye ring, expanded lateral brain case, single middle ear bone, single occipital condyle, lower jaw articulates on quadrate bone, lower jaw composed of several bones and females are heterozygous.
Why are fused bones an advantage for flight?
Fused bones decrease the number of bones and the surface area.
What is the tarsometatarus?
It is the fusion of the foot bones into a single bone to which phalanges are attached.
What is the synsacrum?
It is a fusion of the sacrum and the pelvic girdle.
What is the pygostyl?
It is the fusion of the caudal vertebrae.
What is the tibiotarsus?
It is a fusion of the upper bones of the foot with the tibia.
What is the keel?
It is the sternum bone that is broad and flat. The muscles used for flight attach to this bone.
What is the carpometacarpus?
It is a fusion of the carpal and metacarpal bones.
What is the pygostyle?
It is the fusion of the final few caudal vertebrae into a single bone.
Were the ancestors of Paleognathae (ostrich, Emu) able to fly?
Ancestors such as Archeopteryx were able to fly; thus, this clade is believed to have lost flight.
Describe each of the four toe arrangements.
Anisodactyl has three toes forward and the halux behind. Zygodactyl has two toes forward and two toes behind. Syndactyl has three toes forward and the halux behind, but the middle toe is partially fused to one outside toe. Pamprodactyl has the ability of the two outside toes to be forward or behind.
Describe Booted, Scutellate, and Reticulate scale patterns for the tarsus.
Booted has one single tarsus scale. Scutellate has overlapping scales, and Reticulate has rounded and non-overlapping scales.
