A Brief History of Dinosaurs

By Robin Lloyd, Special to LiveScience

http://www.livescience.com/animals/051201_dinosaur_history.html

Most people think of dinosaurs as big, ferocious and extinct reptiles. That's largely true, but there are some misconceptions.

The word dinosaur, which means "terrible lizard," was coined in 1842, but now we know that dinosaurs aren't lizards, although they share a common ancestor. Lizards as a group are primitive compared to dinosaurs.

Dinosaurs were the largest land animals of all time, but a great number of dinosaurs were smaller than a turkey.

Dinosaurs as a group got bigger over time until an extinction event 65 million years ago wiped out all but bird-like dinosaurs. Scientists don't agree entirely on what happened, but the extinction likely was a double or triple whammy involving an asteroid impact, choking chemicals from erupting volcanoes, climate change and possibly other factors.

Dinosaur Fossil Gallery Avian Ancestors Today's Dinosaurs

Flying on

Yet only the big, classic dinosaurs are extinct. Birds are living dinosaurs, most experts believe. Think of that next time a pigeon strafes you. The carnage continues.

Many people think extinct flying reptiles called pterosaurs were dinosaurs. They were dinosaurs' closest relatives but technically not dinosaurs.

Fossils from the past ten years show that some of the more advanced dinosaurs had feathers or feather-like body covering, but many of them didn't fly and probably didn't even glide. Instead, feathers, rather than being an adaptation for flight, helped these bird-like non-birds stay warm as juveniles.

Hip check

Scientists classify dinosaurs into two major groups based on the structure of the bones in their hips.

Most of the well-known dinosaurs, including Tyrannosaurus rex, Deinonychus, maniraptors, and birds, fall into a category known as Saurischian dinosaurs (pronounced sor-ISK-ee-en). These "reptile-hipped" dinosaurs have a pelvis that points forward, similar to more primitive animals.

Saurischian dinosaurs, often long-necked, have large and sharp teeth, long second fingers, and a first finger that points strongly away from the rest of the fingers.

Ornithischian (pronounced or-neh-THISK-ee-en) dinosaurs, a group that includes horned and frilled ceratopsians, Iguanodontids, armored stegosaurs, and duck-billed hadrosaurs, are more mild-mannered, plant eaters. All have "bird hips," or a backward-pointing pelvis (although ironically they are not the ancestors of birds), which is more stable and gives them that lumbering look. They also have a beak-like bump on the front of their lower jaws that Saurischians lack, and their teeth tend to be smaller and blunter.

Saurischians are divided into two groups – four legged herbivores called sauropods and two-legged carnivores called theropods (living birds are theropods).

Big feet, small brains

Sauropods, such as Diplodocus, Brachiosaurus and Apatosaurus, were among the largest land animals ever, had small brains, and large guts for digesting leaves and grasses.

Theropods, such as velociraptor, allosaurus and albertosaurus, are more agile and have large eyes for spotting prey, sharp teeth for slicing prey, and "grasping claws."

Theropods are the ancestors of extinct birds, including Archaeopteryx, the "first bird," and living birds, which actually evolved from a different branch of the dinosaur family tree than Archaeopteryx.

Scientists are starting to learn about dinosaur behavior. For instance, theropod dinosaurs exhibited some of the same behaviors as living birds, such as sleeping with their heads tucked under their forelimbs and nesting to protect their eggs.

Dinosaur History Rewritten

The Biggest Carnivore: Dinosaur History Rewritten

By Robin Lloyd, Special to LiveScience http://www.livescience.com/animals/060301_big_carnivores.html

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The Age of Dinosaurs ended millions of years ago but paleontologists are still attempting to get a handle on the immense diversity and diverse immensity of these creatures.

Take the report last month that Spinosaurus is now officially the biggest carnivorous dinosaur known to science. This two-legged beast actually strode onto the fossil scene in 1915 when a specimen was described by German paleontologist Ernst Stromer. He figured this theropod (defined as a two-legged carnivore) was bigger than Tyrannosaurus rex, but the original Spinosaurus bones were destroyed by Allied bombs in 1944. So the T. rex reigned as the king size, carnivorous land beast for decades.

Then along came Giganotosaurus 11 years ago.

Now Cristiano Dal Sasso of the Civil Natural History Museum in Milan says Giganotosaurus has been dethroned based on estimates from a new Spinosaurus skull.

So just how do all these carnivores match up?

	Tyrannosaurus rex Length: 40-50 feet Weight: 6 tons Fear factor: teeth up to 13 inches long Lived: 65 million years ago Where: North America
	Giganotosaurus Length: 47 feet Weight: 8 tons Fear factor: 8-inch-long serrated teeth Lived: 95 million years ago Where: Argentina
	Spinosaurus Length: 55 feet Weight: 8 tons Fear factor: long, crocodile-like jaws Lived: 100 million years ago Where: Argentina, Morocco, Tunisia, Algeria

Illustrations by Joe Tucciarone. See More of his Dinosaur Art.

For the ultimate in dinosaur length though, a vegetarian diet prevailed. Herbivorous sauropods dwarfed carnivorous theropod dinosaurs, and most scientists think Argentinasaurus was the longest of all dinosaurs.

Argentinasaurus Length: 120 feet Weight: 100 tons Fear factor: get out of my way Lived: 65 million years ago Where: South America (not to scale)

Paleontologists have only fossils to compare dinosaur sizes, and those fossils are often damaged or incomplete. The same bone from numerous specimens is often lacking, so scientists often must estimate the total size of an animal from a partial skeleton, as with the new Spinosaurus skull fragments.

Greg Erickson of Florida State University says mass, not length, is the best standard for comparing dinosaur size because it gets around the problem of differently shaped animals. Mass is best estimated, he said, by measuring the circumference of the thighbone, which bears much of the animal's weight.

The new Spinosaurus size estimate is "compelling," Erickson told LiveScience. "Spinosaurus was probably considerably longer, and hence perhaps heavier, than T. rex and other large theropods."

Systematics

Systematics

Family tree of the Hadrosauroidea. Representative genera of each tribe are shown to scale.

Taxonomy

The family Hadrosauridae was first used by Edward Drinker Cope in 1869. Since its creation, a major division has been recognized in the group, between the (generally crested) subfamily Lambeosaurinae and (generally crestless) subfamily Hadrosaurinae. Phylogenetic analysis has increased the resolution of hadrosaurid relationships considerably (see Phylogeny below), leading to the widespread usage of tribes (a taxonomic unit below subfamily) to describe the finer relationships within each group of hadrosaurids. However, many hadrosaurid tribes commonly recognized in online sources have not yet been formally defined or seen wide use in the literature. Several were briefly mentioned but not named as such in the first edition of The Dinosauria, under informal names. In this 1990 reference, "gryposaurs" included Aralosaurus, Gryposaurus, Hadrosaurus, and Kritosaurus; "brachylophosaurs" included Brachylophosaurus and Maiasaura; "saurolophs" included Lophorhothon, Prosaurolophus, and Saurolophus; and "edmontosaurs" included Anatotitan, Edmontosaurus, and Shantungosaurus.[4]

Lambeosaurines have also been split into Parasaurolophini (Parasaurolophus) and Corythosaurini (Corythosaurus, Hypacrosaurus, and Lambeosaurus).[5] Corythosaurini and Parasaurolophini as terms entered the formal literature in Evans and Reisz's 2007 redescription of Lambeosaurus magnicristatus. Corythosaurini is defined as all taxa more closely related Corythosaurus casuarius than to Parasaurolophus walkeri, and Parasaurolophini as all those taxa closer to P. walkeri than to C. casuarius. In this study, Charonosaurus and Parasaurolophus are parasaurolophins, and Corythosaurus, Hypacrosaurus, Lambeosaurus, Nipponosaurus, and Olorotitan are corythosaurins.[6]

The following taxonomy includes dinosaurs currently referred to the Hadrosauridae and its subfamilies. Hadrosaurids that were accepted as valid but were not placed in a cladogram at the time of the 2004 review in The Dinosauria,[7] or, in the case of lambeosaurines, the 2007 redescription of Lambeosaurus magnicristatus,[6] are included at the highest level to which they were placed (either then, or in their description if they postdate the papers used here).

19th century bison hunts

A photograph of a 19th-century bison by Eadweard Muybridge, part of a group of images set to motion to illustrate the animal's movement.
http://en.wikipedia.org/wiki/American_Bison

Bison were hunted almost to extinction in the 19th century and were reduced to a few hundred by the mid-1880s. The main reason they were hunted was for their skins, with the rest of the animal left behind to decay on the ground.^[3] After the animals rotted, their bones were collected and shipped back east in large quantities.^[3]

Claims have been made that there was a government initiative to starve the population of the Plains Indians by killing off their main food source, the bison. The Government promoted bison hunting for various reasons: to allow ranchers to range their cattle without competition from other bovines, to weaken the Indian population and pressure them to remain on reservations. The herds formed the basis of the economies of local Plains tribes of Native Americans for whom the bison were a primary food source. Without bison, the Native Americans would be forced to leave or starve.

The railroad industry also wanted bison herds culled or eliminated. Herds of bison on tracks could damage locomotives when the trains failed to stop in time. Herds often took shelter in the artificial cuts formed by the grade of the track winding though hills and mountains in harsh winter conditions. As a result, bison herds could delay a train for days.

This map based on William Temple Hornaday's late-nineteenth-century research.

A pile of bison skulls in the 1870s.

The main reason for the bison's near-demise, much like the actual demise of the passenger pigeon, was commercial hunting.

Bison skins were used for industrial machine belts, clothing such as robes, and rugs. There was a huge export trade to Europe of bison hides. Old West bison hunting was very often a big commercial enterprise, involving organized teams of one or two professional hunters, backed by a team of skinners, gun cleaners, cartridge reloaders, cooks, wranglers, blacksmiths, security guards, teamsters, and numerous horses and wagons. Men were even employed to recover and re-cast lead bullets taken from the carcasses. Many of these professional hunters, such as Buffalo Bill Cody, killed over a hundred animals at a single stand and many thousands in their career. One professional hunter killed over 20,000 by his own count. A good hide could bring $3 in Dodge City, Kansas, and a very good one (the heavy winter coat) could sell for $50 in an era when a laborer would be lucky to make a dollar a day.

The hunter would customarily locate the herd in the early morning, and station himself about 100 meters (100 yd) from it, shooting the animals broadside through the lungs. Head shots were not preferred as the soft lead bullets would often flatten and fail to penetrate the skull, especially if mud was matted on the head of the animal. The bison would drop until either the herd sensed danger and stampeded or perhaps a wounded animal attacked another, causing the herd to disperse. If done properly a large number of bison would be felled at one time. Following up were the skinners, who would drive a spike through the nose of each dead animal with a sledgehammer, hook up a horse team, and pull the hide from the carcass. The hides were dressed, prepared, and stacked on the wagons by other members of the organization.

A bull bison, illustrated in The Extermination of the American Bison.

For a decade from 1873 on there were several hundred, perhaps over a thousand, such commercial hide hunting outfits harvesting bison at any one time, vastly exceeding the take by American Indians or individual meat hunters. The commercial take arguably was anywhere from 2,000 to 100,000 animals per day depending on the season, though there are no statistics available. It was said that the Big .50s were fired so much that hunters needed at least two rifles to let the barrels cool off; The Fireside Book of Guns reports they were sometimes quenched in the winter snow. Dodge City saw railroad cars sent East filled with stacked hides.

As the great herds began to wane, proposals to protect the bison were discussed. Cody, among others, spoke in favor of protecting the bison because he saw that the pressure on the species was too great. But these were discouraged since it was recognized that the Plains Indians, often at war with the United States, depended on bison for their way of life. In 1874, President Ulysses S. Grant "pocket vetoed" a Federal bill to protect the dwindling bison herds, and in 1875 General Philip Sheridan pleaded to a joint session of Congress to slaughter the herds, to deprive the Indians of their source of food.^[4] By 1884, the American bison was close to extinction.

Lophotrochozoa

Roman snail, Helix pomatia

The Lophotrochozoa include two of the most successful animal phyla, the Mollusca and Annelida.[11][12] The former includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods,[13] because they are both segmented. Now this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla.[14]

The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a fan of cilia around the mouth, called a lophophore.[15] These were traditionally grouped together as the lophophorates.[16] but it now appears they are paraphyletic,[17] some closer to the Nemertea and some to the Mollusca and Annelida.[18][19] They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Bryozoa or moss animals.[20]

http://en.wikipedia.org/wiki/Animal

How to Win the War Against Your Dogs Fleas

By: Mini Schnauzer

All dogs pick up fleas, ticks, and chiggers at one time or another, usually during the warm weather months. Even a pampered city pet can pick up a stray flea from a potted plant. Hunting dogs often return home with a collection of chiggers or ticks. Fleas hop from one dog to another with amazing speed and agility. Your pet only needs to greet one flea infested friend in order to acquire the beginning of a flea colony of his own.

External parasites are not a special affliction of dogs. The dog is simply a convenient host for them. We would probably have them too, if our bodies were covered with hair and we ran around without shoes and clothing and sat or slept on the ground. Fleas are the most common, the easiest to detect and to get rid of. Fleas appear as black specks on a fine tooth comb, and a single one can drive a dog crazy.

The worst part of fleas is that they act as hosts to tapeworm larvae, and if your dog swallows one you may end up with a worm problem too. You can trap fleas in a silky smooth coat with a flea comb, but fleas that nestle in the dense undercoat of double coated dogs must be treated with a product that penetrates the skin, and a regular mild treatment is safer than an occasional severe one.

In one day a single flea can bite your pet 400 times, while consuming more than its own bodyweight in blood. Some dogs can contract flea allergy dermatitis, an allergic reaction to the flea’s saliva. The severity and length of the flea season varies depending on what part of the country you live in, but it is best to treat your pet in early spring, (April – May). In northern climates, flea and tick season usually lasts approximately 4 months, but in the extreme south, fleas can live all year long.

There are more than 2000 species of fleas in the United States alone, but the one that attacks most pets is the cat flea, Ctenocephalides Felis. A cat flea can lay up to one egg per hour, and within two days, a wormlike larvae will hatch from those eggs. The eggs are oval, smooth, and about 0.5mm in size. The hatched larvae will range from 1.5 to 5mm in length. The complete cycle from egg to adult takes approximately 30 to 75 days depending on temperature and humidity.

Adult fleas are about 1/16 to 1/8 inch long, are dark reddish brown, wingless, hard bodied, have three pairs of legs and are flattened from side to side. Fleas can jump vertically up to seven inches, and horizontally up to fourteen inches. They have piercing – sucking mouth parts and spines on their body. Adult fleas cannot survive or lay eggs without a blood meal, but may live from two months to one year without feeding.

In order to effectively control an infestation, fleas must be removed from the pet, the home, and the yard. Starting with the pet, there are shampoos, topical treatments, sprays, collars, and oral medications. The least recommended is shampoo, due to the grooming the pet does to his own coat. The pesticides can be toxic if they are consumed in quantity. Topical treatments are better, along with sprays and collars, but the best and most recommended is the oral medication Lufenuron called “Program” from your veterinarian.

To clean the home, all areas frequented by the dog should be cleaned thoroughly by vacuuming, washing bedding and rugs and possible treatment by insecticides. Treating your carpet with a Borate powder such as “Borax” laundry powder works as a poison upon ingestion by the flea, simply sprinkle the powder on your carpets and leave it for a few h ours before vacuuming will rid most homes of their fleas. A second treatment can follow if necessary. It’s cheap, you can do it yourself and there are no insecticides used.

To treat the lawn and around the homes exterior, pyrethroids such as “Archer” or “Nylan”, as well as fenoxy carb such as “Logic” or “Torus” can be effective. Outdoor treatment is usually only done in extreme or severe cases of flea infestation and may not be necessary. You should however keep your lawn trimmed to create a drier, less ideal environment for flea larvae. If you don’t want to handle the pesticides yourself, any licensed professional pest control operator can do the treatment for you.

In summary, you should check with your veterinarian before using any form of flea treatment. Never use products for dogs on a cat, as cats are more sensitive to the pesticide and they groom themselves more thoroughly. Never apply pesticides to young, pregnant, or sick animals, and use alternative methods to control fleas, such as combing frequently with a flea comb, vacuum your home frequently and dispose of the vacuum bag, wash all pet bedding regularly, and bathe your pet with a pesticide free shampoo. Prevention is much easier than dealing with an infestation.

Article Source: http://www.simplepetcare.com/pet-articles

Randy Jones and his partner Brent Jones have been in the pet industry for a long time. Recently they formed Joncopets.com. On the site, customers can read articles about anything pets as well as shop for the latest designer dog clothes, dog collars, dog beds and more for their best friend. Feel free to check out the site at www.joncopets.com