class aves. class aves most paleontologists agree that the common ancestor of all existing birds was...
TRANSCRIPT
![Page 1: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/1.jpg)
CLASS AVES
![Page 2: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/2.jpg)
![Page 3: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/3.jpg)
Class Aves• Most paleontologists agree that the
common ancestor of all existing birds was a type of small, feathered dinosaur.
• Recent fossil discoveries of feathered dinosaurs in China support this hypothesis.
![Page 4: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/4.jpg)
![Page 5: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/5.jpg)
Caudipteryx• Feathered
dinosaur• Flightless• Transitional fossil
– Dinosaur arms– Dinosaur teeth
• Only front of upper jaw
– Bird feathers
![Page 6: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/6.jpg)
Archaeopteryx• Represents an animal that lived about 150
million years ago.• Unlike modern birds, Archaeopteryx had
clawed forelimbs, teeth, and a long tail with vertebrae—all reptilian characteristics.
• In fact, if the feathers had not been preserved in the fossil, Archaeopteryx probably would have been identified as a small dinosaur.
![Page 7: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/7.jpg)
Evolution of Flight• Running Hypothesis
![Page 8: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/8.jpg)
Evolution of Flight• Gliding Hypothesis
![Page 9: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/9.jpg)
Ancestors• Molecular and fossil evidence has
convinced most biologists that birds are actually reptiles.
• The evidence indicates that crocodilians and birds are more closely related to each other than either one of them is to snakes and lizards.
![Page 10: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/10.jpg)
Characteristics• Feathers• No teeth - beaks• Flexible long neck• Scales on legs• Bones with air spaces• Endothermic• Four chambered heart• Bipedal – walk on two legs• Large, yolked, hard-shelled,
amniotic eggs• The parent bird provides
extensive care of the young until it is grown
![Page 11: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/11.jpg)
Adaptations for FlightSpecialized adaptations for flight:
• Honey combed bones– Air cavities– Less weight
• Reduce body weight– No teeth– No urinary bladder– No penis– Only one ovary
![Page 12: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/12.jpg)
Adaptations for Flight• Feathers
– Light weight– Strong
• Enlarged sternum– Flight muscle
attachment
• Long neck– balance sternum
![Page 13: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/13.jpg)
Wings• Most birds have airfoil-shaped wings.
• Wing shape is closely related to wing function.
![Page 14: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/14.jpg)
Flying Styles• Different styles of flying:
– Cardinals and finches rapidly change altitude as they fly, a behavior that helps them avoid predators.
– Falcons and albatrosses are hunting birds that soar, using their wings to gain altitude and then gliding on air currents without flapping.
– Hummingbirds flap their wings as many as 80 times per second, enabling them to hover.
– Penguins are flightless diving birds that use the same basic flight stroke to swim.
– Chickens belong to a group of birds that can fly short distances, but are incapable of long flights.
– Ostriches, emus, and kiwis cannot fly at all.
![Page 15: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/15.jpg)
Beak• Also called “bills”
• Made of keratin
• Nostrils function in breathing
• Variety of beak shapes reflects a wide range of functions
• Beaks are not used for chewing, though some are used to break food into smaller pieces
![Page 16: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/16.jpg)
![Page 17: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/17.jpg)
Feet• Various birds use their feet for walking, perching
on branches, wading, paddling through water, grasping food, in defense, and in some courtship rituals
• Most bird feet are covered in scales• Most birds have four toes on each foot, though
the arrangement varies from species to species
![Page 18: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/18.jpg)
![Page 19: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/19.jpg)
![Page 20: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/20.jpg)
Vision• Up to 8 times keener
than human vision• Each eye moves
independently
![Page 21: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/21.jpg)
Metabolism• Birds have a system of branching air sacs
that function with their lungs in respiration.
• The system of air sacs supplies the high levels of oxygen needed to support a high rate of metabolism for the hard-working flight muscles.
• This high metabolic activity also provides heat for endothermy.
![Page 22: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/22.jpg)
Respiration• One of the most complex respiratory
systems
• Upon inhalation, 75% of the fresh air bypasses the lungs and flows directly into posterior air sacs. – The other 25% of the air goes directly into the lungs.
• When the bird exhales, the used air flows out of the lung and the stored fresh air from the posterior air sacs is simultaneously forced into the lungs.
• A bird's lungs receive a constant supply of fresh air during both inhalation and exhalation.
![Page 23: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/23.jpg)
Circulation• Bird circulatory systems efficiently deliver
oxygen to cells.• Like amphibians and reptiles, birds have two
pathways of blood flow: one from the heart to the lungs and back, and the other from the heart to the rest of the body and back.
• Unlike amphibians and most reptiles, birds have a four-chambered heart with two separate ventricles that keep oxygen-rich blood from the lungs separate from the oxygen-depleted blood that passes through the heart.
![Page 24: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/24.jpg)
Digestion• Crop
– Storage• Proventriculus
– Enzymes• Gizzard
– Grind food (no teeth)• Cloaca
– Waste– Reproduction
![Page 25: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/25.jpg)
![Page 26: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/26.jpg)
Avian Reproduction• In the males of species without a phallus, sperm is
stored within the proctodeum compartment within the cloaca prior to copulation.
• During copulation, the female moves her tail to the side and the male either mounts the female from behind or moves very close to her.
• He moves the opening of his cloaca, or vent, close to hers, so that the sperm can enter the female's cloaca, in what is referred to as a cloacal kiss. This can happen very fast, sometimes in less than one second.
![Page 27: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/27.jpg)
Avian Reproduction• The sperm is stored in the female's cloaca
for anywhere from a week to a year, depending on the species of bird.
• Then, one by one, eggs will descend from the female's ovaries and become fertilized by the male's sperm, before being subsequently laid by the female.
• The eggs will then continue their development in the nest.
![Page 28: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/28.jpg)
Avian Reproduction• Many waterfowl and some other birds, such
as the ostrich and turkey, do possess a phallus.
• Except during copulation, it is hidden within the proctodeum compartment within the cloaca, just inside the vent.
• The avian phallus differs from the mammalian penis in several ways, most importantly in that it is purely a copulatory organ and is not used for dispelling urine.
![Page 29: CLASS AVES. Class Aves Most paleontologists agree that the common ancestor of all existing birds was a type of small, feathered dinosaur. Recent fossil](https://reader035.vdocument.in/reader035/viewer/2022062408/56649ea05503460f94ba2dc7/html5/thumbnails/29.jpg)
Chicks• Altricial
– No feathers– Cannot walk or see– Cannot feed themselves
• Precocial– Down feathers– Can walk and see– Can feed themselves
http://www.youtube.com/watch?v=-Ah-gT0hTto