Wednesday 29 June 2011

dinosaur part -5


What kinds of dinosaurs could fly?











What kinds of dinosaurs could fly?
When most people think of a “flying dinosaur,” they are thinking of a pterodactyl. Although they might look like flying dinosaurs, pterodactyls (and other members of the pterosaur family) are actually not dinosaurs at all! – Technically, pterosaurs are considered flying reptiles, and they are often confused with dinosaurs because they lived at the same time.

One prehistoric animal that is sometimes considered a “flying dinosaur” is the Archaeopteryx. Archaeologists believe that Archaeopteryx had feathers like modern-day birds and a special toe that would have allowed it to hold on to a tree branch. In addition to Archaeopteryx, there are other fossils, such as those of Anchiornis, which are believed to belong to types of dinosaurs that had feathers that may or may not have been used for flight. – Archaeologists don’t know for sure whether or not any of these winged or feathered dinosaurs were able to use these features for flight, but even if not for flying, many guess that they were otherwise used for things like gliding.

As more and more fossils are uncovered, it’s likely that we’ll continue to get new discoveries about cool types of dinosaurs – winged, feathered, flying, and otherwise!

The Type of Environment Dinosaurs Lived inthumbnail
Ferns and conifers characterized much of the dinosaurs' environment.

Dinosaurs lived during the Mesozoic era, between 248 million and 65 million years ago. During their tenure on the Earth, the continents shifted and the environment changed accordingly. Dinosaurs filled niches that had been abandoned during the mass extinction event of the previous era, so that they inhabited much of the Earth. Although the Earth's environment seems to have been somewhat more consistent during the Mesozoic than it is today, the dinosaurs' habitats were still likely to have been somewhat varied. Despite this, fossil records of both plants and animals allow researchers to make some general statements about their environment.

  1. The Continents

    • At the beginning of Mesozoic, all of the Earth's continents we joined into one massive continent called Pangaea. This impacted the distribution of dinosaurs by allowing for massive migration ranges at the beginning of the era. Over time, it split into two continents, the northern continent of Laurasia and the southern Gondwana, with dinosaurs inhabiting portions of each. By the end of the Mesozoic, the continents had split into the forms that we know today. Laurasia split into North America and Eurasia, and Gondwana split into South America, Africa, Australia and Antarctica.

    Climate

    • The climate during much of the dinosaurs' time appears to have been generally warm and dry, except in the tropical middle latitudes. High carbon dioxide levels impacted the ocean by raising water temperature and reducing the oxygen levels. The absence of polar ice caps is also suggestive of a warmer climate during this era. Areas that had been previously covered with glaciers and tundra were now characterized by deciduous forests. Middle latitudes featured tropical conditions, and lower latitudes were arid. Seasonal changes appear to have been less dramatic than they are today, and most plant cycles appear to have been controlled by changes in light rather than changes in temperature.

    Vegetation

    • The vegetation available to the dinosaurs was dominated by seed plants. Ferns were prevalent, especially in the southern regions. The north was characterized by conifers, such as pine trees. The highest latitudes featured deciduous forests dominated by the ginkgo family of trees. Middle latitudes consisted of tropical forests dominated by ferns, and the lowest latitudes were dry savannas and deserts. Flowering plants, including grasses, began to appear toward the end of the Mesozoic.

    Animals

    • Dinosaurs emerged to fill the void left by the massive extinction event that marked the end of the Permian period of the Paleozoic era and the beginning of the Mesozoic. They shared the oceans with new species of fish, swimming reptiles and mollusks such as clams and snails. On land, dinosaurs competed with other reptiles, including turtles, crocodiles and the ancestors of lizards and snakes. Flying reptiles appeared during this era and eventually evolved into birds as scales were replaced with feathers. Insects needed to pollinate the new flowering plant species, such as butterflies, flies and wasps, appeared, as did the first mammals.


Read more: The Type of Environment Dinosaurs Lived in | eHow.co.uk http://www.ehow.co.uk/info_8459840_type-environment-dinosaurs-lived.html#ixzz1Q7UtZ17A

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