+ 1-888-787-5890  
   + 1-302-351-4405  
 
 
 
 

Essay/Term paper: Dinosaurs

Essay, term paper, research paper:  Biology

Free essays available online are good but they will not follow the guidelines of your particular writing assignment. If you need a custom term paper on Biology: Dinosaurs, you can hire a professional writer here to write you a high quality authentic essay. While free essays can be traced by Turnitin (plagiarism detection program), our custom written essays will pass any plagiarism test. Our writing service will save you time and grade.



DINOSAURS



Dinosaur is the name of large extinct reptiles of the Mesozoic Era, during which they were the dominant land animals on Earth. The term was proposed as a formal zoologic name in 1842 by the British anatomist Sir Richard Owen, in reference to large fossil bones unearthed in southern England. The various kinds of dinosaurs are classified in two formal categories, the orders Saurischia and Ornithischia, within the subclass Archosauria.

The first recorded dinosaur remains found consisted of a few teeth and bones. They were discovered in 1882 in Sussex, England, by an English doctor, Gideon Mantell, who named them iguanodon. About the same time, other fossil teeth and bones were found near Oxford, England, by Rev. William Buckland. These were named Megalosaurus. Thousands of specimens have since been discovered nearly worldwide.

Different types of dinosaurs varied greatly in form and size, and they were adapted for diverse habitats. Their means of survival can only be identified from their fossil remains, and some identifications are in dispute. They ranged in weight from 4 to 6 lb., in the case of the compsognathus, and up to 160,000 lb., in the case of the brachiosaurus. Most dinosaurs were large, weighing more than 1,100 lb., and few weighed less than 100 lb. Most were herbivores, but some saurischians were carnivorous. The majority were four-footed but some ornithischians and all carnivores walked on their hind legs.

Always classified as reptiles, dinosaurs have traditionally been assumed to have been reptilian in their physiology, cold-blooded, and ectothermic. In recent years several different lines of evidence have been interpreted as indicating that dinosaurs may have had warm blood and high rates of metabolism, comparable to birds and mammals. Evidence supporting this view includes upright posture and carriage; mammallike microscopical structure of bones; skeletal features suggestive of high activity; and specialized food-processing dentitions and low ratios of dinosaurian predators to prey animals, both suggesting high food requirements. The evidence is not conclusive--all the facts can be alternatively explained--but some dinosaurs may have been endothermic.

The reproductive means of most dinosaurs is as yet unknown. Fossil eggs, attributed to one of the horned dinosaurs and a sauropod, have been discovered in Mongolia and France. Fragments that are presumed to be of dinosaur eggs have also been found in Brazil, Portugal, Tanzania, and in the United States, Colorado, Montana, and Utah. In Montana, Utah, and Alberta, Canada, fossils of unhatched dinosaur eggs have been discovered. This evidence indicates egg-laying reproduction in dinosaurs, like most modern reptiles. A few scientists believe that some dinosaurs may have given birth to living young, but no conclusive evidence has yet been found to support this.

The two orders of dinosaurs are distinguished by numerous features, the most diagnostic being the arrangement of the three bones of the pelvious. In saurischians, these bones were arranged in a triradiate pattern similar to that of modern crocodilians and lizards; the term Saurischia means lizard hip. The ornithischian pelvis was usually rectangular or tetraradiate; hence the name, which means bird hip.

During the 140-million-year reign of the dinosaurs, many new varieties evolved and older kinds died out. Not all kinds became extinct at once; but the last of the dinosaurs disappeared at the end of the Cretaceous. Many other animal kinds died out at about the same time, including the ichthyosaur, mosasour, plesiosaur, flying reptile, and a variety of lower organisms. What brought about such widespread extinction among so many different kinds of organisms is not known; it must, however, have involved major changes in the environment. Their extinction has been attributed to many causes, including cosmic radiation, exploding supernova, world-wide fluctuations in sea level, acid rain caused by volcanic activity, climatic change, and continental drift. Independent evidence indicates that sea levels did fall and temperatures dropped at the end of the Mesozoic Era, a time when continents were drifting apart and new mountain ranges were rising. Although none of these conditions is likely to have been solely responsible for the extinction of the dinosaurs, collectively they may have been important.

Whatever the cause, the dinosaurs are now gone. In a way, however, they may remain. That is, many paleontologists consider birds almost certainly to have evolved from some small bipedal dinosaur during the Jurassic. If so, the children of the dinosaurs still exist today.


 

Other sample model essays:

Critical Essays / Dionysius
Dionysus Dionysus was the most widely worshipped and popular god in ancient Greece. It's not difficult to see why; he was their god of wine, merriment, ritual dance, warm moisture, and later, ...
Critical Essays / Dionysus And Semele
Sanez Pezeshki Per.2, English 2 Tuesday, December 24, 1996 MYTHOLOGY: DIONYSUS AND SEMELE Semele was the daughter of Cadmus and Harmonia, king and queen of The...
Critical Essays / Diplomacy At Work
Diplomacy at Work In today"s world political society, the use of diplomacy is a tool that allows countries to work out their differences in an attempt to avoid war. Diplomacy is of...
Critical Essays / Dirtbiking
Dustin Leonhardt Per. 4/5 Feb. 25,1997 Dirtbiking Imagine speeding through a construction site at 80 miles per hour. Not knowing what terrain is coming up next. You could speed away and be ...
Critical Essays / Disaster Hits Village
Disaster hits village ! Three years ago something terrible happened in my hometown. It all begun one evening when I was sitting and watching on the local TV station. They interrupted the tv...
Discuss some of the issues raised in "An Inspector Calls" and show how Priestly expresses his own viewpoint in the play. 22nd March 1997 Martin Howitt 11W The play is set in the1912 on ...
Carlos Vela December 6, 1996 English 1A 1:00-1:50pm Essay Final 1. Discuss the significance of food in Like Water for Chocolate. Food equals memory and memory equals immortality. In t...
William Shakespeare's "Macbeth" is a play in which a man by the name of Macbeth, who is presented as a mature man with an uncertain character. At the beginning of the story, Macbeth's character w...
Representations of Masculinity and Femininity in Miguel Street It has been said about V.S. Naipaul's novel Miguel Street that "One of the recurrent themes... is the ideal of manliness"...
Disjunction vs. Communion in Raymond Carver"s Short Stories Raymond Carver, poet, essayist, and short story writer, was very different from some other writers i...
Experience with Dream Essay - Reliable and great customer service. Quality of work - High quality of work.
Browns Mills, New Jersey, United States
Dream Essay - Very reliable and great customer service. Encourage other to try their service. Writer 91463 - Provided a well written Annotated Bibliography with great deal of detail per the rubric.
Browns Mills, New Jersey, United States
it is always perfect
Frederick, Maryland, United States
The experience with Dream Essay is stress free. Service is excellent and forms various forms of communication all help with customer service. Dream Essay is customer oriented. Writer 17663 is absolutely excellent. This writer provides the highest quality of work possible.
Browns Mills, New Jersey, United States
Only competent & proven writers
Original writing — no plagiarism
Our papers are never resold or reused, period
Satisfaction guarantee — free unlimited revisions
Client-friendly money back guarantee
Total confidentiality & privacy
Guaranteed deadlines
Live Chat & 24/7 customer support
All academic and professional subjects
All difficulty levels
12pt Times New Roman font, double spaced, 1 inch margins
The fastest turnaround in the industry
Fully documented research — free bibliography guaranteed
Fax (additional info): 866-332-0244
Fax (additional info): 866-308-7123
Live Chat Support
Need order related assistance?—Click here to submit a inquiry
© Dreamessays.com. All Rights Reserved.
Dreamessays.com is the property of MEDIATECH LTD