Invasive Species - Melaleuca Tree essays

Invasive Species - Melaleuca Tree essays Introducing a nonnative species into an environment can cause some unexpected problems to the habitat and to native species. Although some introduced species are beneficial, such as food crops, game animals and pets, others can have a negative effect on the environment. Fifteen percent of species introduced have become invaders causing devastation to farms, health hazards for humans, invasion of natural areas, and the replacement of native species. If a plant or animal is introduced to a new area with similar plants or animals it causes competition for food or space. One species can be eliminated because of this. An example of a nonnative species being introduced into the United States and causing unforseen problems is the Australian melaleuca tree being introduced to Florida. The melaleuca tree is an ornamental plant that grows to be about eighty feet tall. The bark of the tree is spongy and its leaves are up to five inches long. The flowers of the melaleuca tree are white and small and the fruit that the tree produces are woody capsules with many seeds. This tree was introduced into Florida swamps in the 1880's because people wanted to dry up the useless swamps. They have since become a problem for the everglades because they invade moist open habitats forming dense and often impenetrable stands of trees. Native wildlife in these areas are threatened because the melaleuca trees crowd out beneficial native plants. The tree can spread very fast because it produces large amounts of seeds and most of the seeds that spread grow into large trees. Only fifty years after the tree was introduced into the United States it had already spread over hundreds of thousands of acres. By 1967, it was in Everglades National Park, and in 1993 it covered 488,000 acr es in south Florida. Melaleuca trees produce hot crown fires that result in mortality for native trees and pose a threat to people and animals in th ...

Mamenchisaurus - Facts and Figures

Mamenchisaurus - Facts and Figures Name: Mamenchisaurus (Greek for Mamenxi lizard); pronounced ma-MEN-chih-SORE-us Habitat: Forests and plains of Asia Historical Period: Late Jurassic (160-145 million years ago) Size and Weight: Up to 115 feet long and 50-75 tons Diet: Plants Distinguishing Characteristics: Unusually long neck, composed of 19 elongated vertebrate; long, whiplike tail About Mamenchisaurus If it hadnt been named after the province of China where it was discovered, in 1952, Mamenchisaurus might better have been called Neckosaurus. This sauropod (the family of gigantic, herbivorous, elephant-legged dinosaurs that dominated the late Jurassic period) wasnt quite as thickly built as more famous cousins like Apatosaurus or Argentinosaurus, but it possessed the most impressive neck of any dinosaur of its kindover 35 feet long, composed of no less than nineteen huge, elongated vertebrae (the most of any sauropods with the exception of Supersaurus and Sauroposeidon). With such a long neck, you might assume that Mamenchisaurus subsisted on the uppermost leaves of tall trees. However, some paleontologists believe that this dinosaur, and other sauropods like it, was incapable of holding its neck to its full vertical position, and instead swept it back and forth close to the ground, like the hose of a giant vacuum cleaner, as it feasted on low-lying shrubbery. This controversy is closely tied to the warm-blooded/cold-blooded dinosaur debate: its difficult to imagine a cold-blooded Mamenchisaurus having a robust enough metabolism (or a strong enough heart) to enable it to pump blood 35 feet straight up into the air, but a warm-blooded Mamenchisaurus presents its own set of problems (including the prospect that this plant-eater would literally cook itself from the inside out). There are currently seven identified Mamenchisaurus species, some of which may fall by the wayside as more research is conducted on this dinosaur. The type species, M. constructus, which was discovered in China by a highway construction crew, is represented by a 43-foot-long partial skeleton; M. anyuensis was at least 69 feet long; M. hochuanensis, 72 feet long; M. jingyanensis, up to 85 feet long; M. sinocanadorum, up to 115 feet long; and M. youngi, a relatively runty 52 feet long; a seventh species. M. fuxiensis, may not be a Mamenchisaurus at all but a related genus of sauropod (provisionally named Zigongosaurus). Mamenchisaurus was closely related to other long-necked Asian sauropods, including Omeisaurus and Shunosaurus.