سفارش تبلیغ
صبا ویژن
Is there anybody to hear the voice of fossils
  •   longlife
  • How long could a dinosaur live?

    Animal lifespans relate in part to their body size and in part to their type of metabolism. Dinosaur lifespans probably varied in length from tens of years to hundreds of years. Their possible maximum age can be estimated from the maximum lifespans of modern reptiles, such as the 66-year lifespan of the common alligator (Alligator mississippiensis) and the impressive lifespan of a Black Seychelles Tortoise (Geochelone (Aldabrachelys) sumeirei). One specimen of this now-extinct species, which was an adult when captured, lived a record 152 years in captivity (1766-1918) and had an accidental death. These estimates, based on lifespans of cold-blooded animals, would be too long if dinosaurs had metabolisms more similar to modern birds and mammals.



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 9:34 عصر)

  • نظرات دیگران ( )

  •   how are dinasours named
  • How are dinosaurs named?

    Dinosaurs generally are named after a characteristic body feature, after the place where they were found, or after a person involved in the discovery. Usually the name consists of two Greek or Latin words (or combinations); in order, these are the genus (plural, genera) and the species name. For example, the Greek and Latin combination (binomen) Tyrannosaurus rex means "king of the tyrant lizards." Biologists name modern animals exactly the same way. Some examples include humans (Homo sapiens), domestic dogs (Canis familiaris), golden eagles (Aquila chrysaetos), box turtles (Terrapene carolina), and rattlesnakes (Crotalus horridus).



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 9:32 عصر)

  • نظرات دیگران ( )

  •   when did dinasours become extinct
  • When did dinosaurs become extinct?

    Dinosaurs went extinct about 65 million years ago (at the end of the Cretaceous Period), after living on Earth for about 165 million years. If all of Earth time from the very beginning of the dinosaurs to today were compressed into 365 days (1 calendar year), the dinosaurs appeared January 1 and became extinct the third week of September. (Using this same time scale, the Earth would have formed approximately 18.5 years earlier.) By comparison, people (Homo sapiens) have been on earth only since December 31 (New Year"s eve). The dinosaurs" long period of dominance certainly makes them unqualified successes in the history of life on Earth

  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 9:30 عصر)

  • نظرات دیگران ( )

  •   Extinction
  • Why did the dinosaurs die out?

    There are dozens of theories to explain a probable cause or causes. Throughout the Mesozoic Era, individual dinosaur species were evolving and becoming extinct for various reasons. The unusually massive extinction at the end of the Cretaceous exterminated the last of the dinosaurs, the flying reptiles, and the large swimming reptiles, as well as many other marine animals. There is now widespread evidence that a meteorite impact was at least the partial cause for this extinction. Impact craters are visible on most planets in our solar system. A spectacular example of this was witnessed in 1994, when Jupiter was struck by a series of cometary fragments.

  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 9:29 عصر)

  • نظرات دیگران ( )

  •   dinasours and social behaviours
  • Were dinosaurs social animals?

    Some dinosaurs were social creatures. Recently discovered evidence indicates that they travelled together and that some may even have migrated (because dinosaur fossils have been found above the Arctic Circle, where food supply would have been seasonal). Grouped hadrosaur nest sites have been found with badly crushed eggshells and skeletons of baby dinosaurs (with slightly worn teeth) still in the nests, suggesting that some babies stayed in their nests after hatching and probably were fed by parents.



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 9:23 عصر)

  • نظرات دیگران ( )

  •   people and dinasours
  • Did people and dinosaurs live at the same time?

    No! After the dinosaurs died out, nearly 65 million years passed before people appeared on Earth. However, small mammals (including shrew-sized primates) were alive at the time of the dinosaurs. Many scientists who study dinosaurs (vertebrate paleontologists) now think that birds are direct descendants of one line of carnivorous dinosaurs, and some consider that they in fact represent modern living dinosaurs. This theory remains under discussion and shows that there is still much we don"t know about dinosaurs.



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 8:18 عصر)

  • نظرات دیگران ( )

  •   where did they live
  • Where did dinosaurs live?

    Paleontologists now have evidence that dinosaurs lived on all of the continents. At the beginning of the age of dinosaurs (during the Triassic Period, about 230 million years ago) the continents we now know were arranged together as a single supercontinent called Pangea. During the 165 million years of dinosaur existence this supercontinent slowly broke apart. Its pieces then spread across the globe into a nearly modern arrangement by a process called plate tectonics. Volcanoes, earthquakes, mountain building, and sea-floor spreading are all part of plate tectonics, and this process is still changing our modern Earth.



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 8:18 عصر)

  • نظرات دیگران ( )

  •   how many are known
  • How many types of dinosaurs are known?

    Approximately 700 species have been named. However, a recent scientific review suggests that only about half of these are based on fairly complete specimens that can be shown to be unique and separate species. These species are placed in about 300 valid dinosaur genera (Stegosaurus, Diplodocus, etc.), although about 540 have been named. Recent estimates suggest that about 700 to 900 more dinosaur genera may remain to be discovered.

    Most dinosaur genera presently contain only one species (for example, Deinonychus) but some have more (for example, Iguanodon). Even if all of the roughly 700 published species are valid, their number is still less than one-tenth the number of currently known living bird species, less than one-fifth the number of currently known mammal species, and less than one-third the number of currently known spider species.



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 8:16 عصر)

  • نظرات دیگران ( )

  •   colors
  • What colors were dinosaurs

    Direct fossil evidence for dinosaur skin color is unknown. Paleontologists think that some dinosaurs likely had protective coloration, such as pale undersides to reduce shadows, irregular color patterns ("camouflage") to make them less visible in vegetation, and so on. Those dinosaurs that had enough armor, such as the stegosaurs and ceratopsians, may not have needed protective coloration but may have been brightly colored as a warning to predators or as a display for finding a mate. Most dinosaurs probably were as brightly colored as modern lizards, snakes, or birds



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 8:15 عصر)

  • نظرات دیگران ( )

  •   the greatest one
  • Which was the smartest dinosaur?

    Although there is no direct way to measure a dinosaur"s intelligence, one of the few possible measures of intelligence might be a large brain in a small body. The genus that perhaps fits this deion best was the Cretaceous bird-like dinosaur Troodon, which also may have had binocular vision (depth perception) and excellent eyesight and was built for speed. Even so, this dinosaur was probably not as "intelligent" as most modern birds and mammals.

     



  • نویسنده: کوروش بهارمست(پنج شنبه 86/10/20 ساعت 8:14 عصر)

  • نظرات دیگران ( )

    <   <<   6   7   8   9      >

  •   لیست کل یادداشت های این وبلاگ
  • sigillaria
    [عناوین آرشیوشده]
  •    RSS 

  •   خانه

  •   شناسنامه

  •   پست الکترونیک

  •  پارسی بلاگ



  • کل بازدید : 40483
    بازدید امروز : 3
    بازدید دیروز : 52
  •   مطالب بایگانی شده

  • fossils
    زمستان 1386

  •   درباره من

  • Is there anybody to hear the voice of fossils
    کوروش بهارمست

  •   لوگوی وبلاگ من

  • Is there anybody to hear the voice of fossils

  •   اشتراک در خبرنامه
  •  

  •   اوقات شرعی
  • اوقات شرعی


  •   آهنگ وبلاگ من