Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: neilep on 22/08/2007 14:19:12
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Greetings,
How are you today ?...I had an awful headache yesterday but am feeling better now !
I hope you are too !
This is a Swallow:
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Nice isn't it ?
I am reliably informed that it has hollow bones to help it remain buoyant in flight (thanks Paul)
I was wondering...does this bird also have hollow bones?
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Notice the handsome young bloke upon it ?..
Anyway...as we all know T-rex was just a big chicken !...did he have hollow bones too ?
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http://en.wikipedia.org/wiki/Bird_anatomy#Skeletal_system
Birds have many bones that are hollow with criss-crossing struts or trusses for structural strength. The number of hollow bones varies among species, though large gliding and soaring birds tend to have the most. Respiratory air sacs often form air pockets within the semi-hollow bones of the bird's skeleton. Some flightless birds like penguins and ostriches have only solid bones, further evidencing the link between flight and the adaptation of hollow bones.
http://www.newscientist.com/article.ns?id=dn7195
Bones are built by cells called osteocytes which are nourished by a rich fabric of blood vessels. The osteocytes secrete proteins which collect the calcium compounds that give bones their strength.
To see what remained of this internal structure, Schweitzer soaked samples of the core of the bone in a solution that dissolved the calcium compounds. This left what she describes as "a flexible vascular tissue that demonstrates great elasticity and resilience".
For comparison, she then examined ostrich bones, as these birds are the largest and closest living relatives of T. rex. She found similar structures when she removed the calcium from the ostrich bones and treated the mixture with enzymes to break down collagen fibre in the bony matrix.
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Incidentally, if you want to try and find out for yourself (being the sort of disbelieving fella you are, and needing to see everything with your own eyes), then here you can get some ostrich bones: http://www.kninekountry.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=KK&Category_Code=OSB
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I took these from this site after doing google search on Hollow legged birds!
Explore the ancient southwest!
http://www.rain.org/campinternet/southwest/dinosaurs/triassac-gallery.html
Dinosaurs - Triassic Gallery
In the Triassic period, only the lizard-hipped dinosaurs lived in the Ancient Southwest. There were two legged meat eaters called Theropods, and there were four legged plant eaters called Sauropods.
Coelurosaurs
In New Mexico, the oldest type of dinosaur in North America has been found, and they were found in family groups. These early dinosaurs are called Coelurosaurs and were small Theropods that stood on two slender hind legs, had long necks, small heads, short front arms, and long tails. Their name means they were hollow-boned dinosaurs, which made them light and probably fast runners.
The Coelurosaurs are one of the few Dinosaurs with relatives living in all three periods of the Mesozoic Era. These hollow-boned creatures are the ancestors of today's birds, and make a link that proves dinosaurs are not really extinct - they evolved into birds!
An example of a Coelurosaurs is a Coelophysis, Paleontologist and Ichnologists think they lived in herds, cared for their young, and ate meat and insects.
Prosauropods
Another very different types of dinosaur lived in the southwest during the last half of the Triassic. These were Prosauropods, meaning ancestors of the Sauropods. Sauropods are the huge four legged plant eaters - like Brontosaurs - many of us easily recognize as a major dinosaur type. The Prosauropods were smaller than their descendents and had the ability to run on their hind legs or stand on four legs to eat or drink.
The Anchisaurus was a Prosauropod measuring eight feet in length, his long neck and long heavy tail together were twice as long as his body. He could stand and walk on all fours, but probably raised up on his stronger hind legs to run, using his four toes for balance. The Anchisaurus was a plant eater with a long flexible neck helpful in gathering leaves from tall tress, and to drink with out getting down on its belly.
Segisaurus
A small rabbit-sized dinosaur that lived in the Ancient southwest was the Segisaurus, named after the canyon where it was found in Arizona. This small creature was apparently a fast runner, ate small reptiles, and it bones were solid, not hollow. The Segisaurus lived during the late Triassic and Early Jurassic.
Dilophosaurus
The Dilophosaurus was a crest headed dinosaur that ran on two strong heavy back legs weighed about 1,000 pounds, and measured 20' nose to tail. He lived in Arizona during the late Triassic and early Jurassic when it was a desert. He had sharp dagger-like teeth for eating prey and the claws on his front and hind hands and feet helped him catch his meals. His unusual head crest was made o two side be side crests on the top of his head. When found in Arizona, there was a group of three discovered together, implying it may have run in a small herd.
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http://en.wikipedia.org/wiki/Theropoda
Among the features linking theropods to birds are the three-toed foot, a furcula (wishbone), air-filled bones and (in some cases) feathers and brooding of the eggs.
http://en.wikipedia.org/wiki/Tyrannosaurus_rex#Description
The neck of T. rex formed a natural S-shaped curve like that of other theropods, but was short and muscular to support the massive head. The two-fingered forelimbs were very small relative to the size of the body, but heavily built. In contrast, the hindlimbs were among the longest in proportion to body size of any theropod. The tail was heavy and long, sometimes containing over forty vertebrae, in order to balance the massive head and torso. To compensate for the immense bulk of the animal, many bones throughout the skeleton were hollow. This reduced the weight of the skeleton while maintaining much of the strength of the bones.
http://www.gma.org/surfing/antarctica/penguin.html
Penguins are designed for life in the sea. Some species spend as much as 75% of their lives in the water. (They lay their eggs and to raise their chicks on land.) Heavy, solid bones act like a diver's weight belt, allowing them to stay underwater.
Most birds have hollow bones to make their bodies light enough to become air-borne. But the penguins' heavy, solid bones help them float lower in the water.
http://www.zoobooks.com/twentyarchive/penguin/print/questions.html
8. What makes penguin bones different from the bones of flying birds?
A. Penguin bones are made of cartilage.
B. Penguin bones are solid instead of hollow.
C. Penguin bones can’t be broken.
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Segisaurus
A small rabbit-sized dinosaur that lived in the Ancient southwest was the Segisaurus, named after the canyon where it was found in Arizona. This small creature was apparently a fast runner, ate small reptiles, and it bones were solid, not hollow. The Segisaurus lived during the late Triassic and Early Jurassic.
Wait, if rabbit-sized dinosaurs during that time period ate small-reptiles, does it mean that at that time regular-sized lizards already existed?