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History of dinosaurs essay
History of dinosaurs essay
Connection between birds and dinosaurs
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The Debate Over Birds and Feathered Dinosaurs
Because dinosaurs are animals that lived millions of years ago, we are entirely dependent on the fossils that they have left behind for any understanding that we hope to gain. As any paleontologist will tell you, fossil hunting is difficult. There are no certainties, no guarantees. A certain amount of luck is as valuable as any scientific knowledge.
Every so often a discovery is made that attempts to shake up pre-conceived notions of how the dinosaurs actually lived or how they came to be. On June 22, 2000, in Oregon, scientists announced the discovery of the oldest known animal to have feathers. Though no records indicate how the age of the animal was determined, the fossil was dated at 220 million years old. It lived at the time of the very earliest dinosaurs, and about 75 million years before the first known bird.1[1]
The scientists assert that Longisquama insignis is not a dinosaur, and may be one of the earliest bird ancestors. The animal was a small lizard-sized glider, with four legs and feathers on its body. It is believed that the feathers were used for gliding, as the ancient creature lacks the necessary structures for flying.1
Before the announcement of Longisquama, the earliest known animal with feathers was Archaeopteryx, a bird capable of flight that lived roughly 145 million years ago.1 It has been proposed that Archaeopteryx is the intermediary between birds and predatory theropods, such as Deinonychus.2 The discovery that Longisquama had feathers strongly questions the evolutionary origins of Archaeopteryx, and additionally may discredit the belief that it is the link between birds and dinosaurs.
However, th...
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5 The Field Museum. (2002). New Species Clarifies Bird-Dinosaur Link. Science Daily [online], 14 Feb 2002. Available at http://www.sciencedaily.com/releases/2002/02/020214080242.htm
6 Monastersky, R. (1998). Feathered Dinosaurs Found in China. Science News Online [online], 27 June 1998. Available at http://www.sciencenews.org/pages/sn_arc98/6_27_98/fob1.htm
7 H, J R. (1995). Are Birds Really Dinosaurs? [online] Available at http://www.ucmp.berkeley.edu/diapsids/avians.html
8 Rusatte, B. (1997). Controversial Fossil Claimed to Sink Dinosaur-Bird Link. [online] Available at http://www.geocities.com/CapeCanaveral/Galaxy/8152/longisquama.html
9 Brett-Surman, M K, et al. Top 10 Misconceptions about Dinosaurs. [online] Available at http://www.nmnh.si.edu/paleo/faq.html
Ceratopsians and Pachycephalosaurs are closely related in their characteristics. Ceratopsians processed a saddle-shaped boney frill that extended from the skull to the neck and typically had horns over the nose and eyes. The most popular was the triceratops, which could reach over 26 feet and weigh in excess of twelve metric tons. Their frills served as two major functions. It protected the vulnerable neck from being harmed. The second major function that the frill provided was due to the fact that the frill contained a network of blood vessels on its underside, which were used as a means to get rid of excess heat. The Pachycephalosaurs were considered to be bipedal. They were also found to have thick skulls, flattened bodies, and tail that were covered in an array of body rods. Pachycephalosaurs were thought to have been more than fifteen feet long and processed a skull that was surrounded by a rounded dome of solid bone. It was thought that they used their heads in combat or mating contests, but that was disproved fairly recently, which I will discuss later in the paper. Both Ceratopsians and Pachycephalosaurs were “bird-hipped” and both of these suborders contained a backwards pubic bone. Both were Marginocephilia, or “fringed heads”, which is one of three clads under the Orinthiscia order. They were also herbivore dinosaurs that inherited their fringe at the back of the skull from earlier ancestors.(2) Their classi...
Paul, Gregory S. (2002). "Looking for the True Bird Ancestor". Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins University Press. pp. 171–224. ISBN 0-8018-6763-0.
Of course it was the movie Jurassic Park who seemed to coin the phrase “Dino DNA.” This movie gave the public the thought that, a) it is possible to find dinosaur DNA and b) we can clone dinosaurs from this DNA. This essay is not going to pick apart Jurassic Park’s scientific value, however it will share the current knowledge and information on dinosaur DNA. The discovery of DNA is important because it may uncover different bits of information. The idea of cloning dinosaurs, especially at this point is out of the question. It is really hard to clone living animals today, with full DNA and genome strands, we can’t even think about recreating animals millions of years ago.
Elderly folks are eminently mature and have the finest instinct about what is right and wrong though It’s challenging to change someone’s point of view in a matter like this. When such injustice takes place, it de-motivates senior workers from their work. In an article over Ageists by Vincent J Roscigno, he states facts about different views on older Americans in general and in workplaces such as, “most of the population consists of biases and preconceptions, and the accused are unashamed in their views of older Americans. Those who believe that younger employees have much more value than senior employees are inserting a strong assumption based on their age. “Ageist attitudes and discrimination is what results in lower levels of overall organizational commitment to older workers, and a “push” out of a particular workplace.” Just because of an older employee’s depiction, such unfairness circulates in workplaces which cause false impressions of older
We use dinosaurs to represent the changes in nature that have occurred throughout time. Studies found that although the “oldest rock did not show evidence of life, the progression of plant and animal life that changed in recognizable intervals, from ancient life, age of reptiles to the age of mammals” (Dino Nature Metaphor, slide 6), measured the age of the earth. When we think of dinosaurs in relation to nature, we think of that very powerful force that controls the cycle of life. Nature was able to yield such magnificent ferocious creatures that walked the earth and then take them back when they served nature’s purpose. Dinosaurs fit perfectly in nature’s constant
Fossil evidence suggests that the Cathartid (New World) vultures have been around for quite some time with two fossil species dated from the early Oligocene (about 35 million years ago). During the Pliocene and Pleistocene (about 2 million years ago) th...
The first evidence for feathers in tyrannosauroids came from the small species Dilong paradoxus, found in the Yixian Formation of Chinaback in 2004. As with many other theropods uncovered in the Yixian, the fossil skeleton was preserved in a shell of filamentous structures which are commonly known as the precursors
Linhenykus is an extinct genus of alvarezsaurid theropod dinosaur from the Late Cretaceous of Inner Mongolia, China. It is the most known member of the Parvicursorinae. The genus gets its name from Linhe, a city near the site where the fossil was first found and Greek nykus, . The specific name is derived from Greek monos, and daktylos, a reference to the fact that it is the only known non-avian dinosaur to have had but a single digit.
The debate of whether dinosaurs were cold blooded or warm blooded has been ongoing since the beginning of the century. At the turn of the century scientists believed that dinosaurs had long limbs and were fairly slim, supporting the idea of a cold blooded reptile. Recently, however, the bone structure, number or predators to prey, and limb position have suggested a warm blooded species. In addition, the recent discovery of a fossilized dinosaur heart has supported the idea that dinosaurs were a warm blooded species. In this essay, I am going to give supporting evidence of dinosaurs being both warm and cold blooded. I will provide background information on the dinosaur that was discovered and what information it provides scientists.
An age discrimination action happens when an employee or job applicant receives less favorable or unfair treatment because of how old they are. Both state and federal Age Discrimination in Employment Act prohibit employers from discriminating against protected employees or prospects because of how old they are. Workers 40 and older are protected by the act. The ADEA applies to organizations with 20 plus employees, including labor organizations, employment agencies, state and local governments, and the federal government.
An uncommon, peculiar approach to mundane extinction of the dinosaurs theories arose from Gould’s writing as he explained the sex theory (Gould 404). At first, the mere title
The Age Discrimination in Employment Act of 1967 is an act that was passed that clearly states that employers can’t be discriminate against someone based on their age 40 and older. The older adults are trying so hard to hold onto their jobs with dear life, because if not they will be nudged out and pushed aside. Not because of anything but rather because of their age. Age discrimination is on the rise as young as 50 years old. Age discrimination can happen to anyone regardless of your race, ethnic backgrounds or sexual orientation. A study was published in the Journal of Age Ageing and in the report it said that British People 50 years old and older faces discrimination about one third of them. In a resent survey older adults says job insecurity
...pdated 1995, accessed 3 Sept. 2000), Dino Buzz – What killed The Dinosaurs ? – Current Arguments,
Norell, Mark, Lowell Dingus, and Eugene S. Gaffney. "Why Did Nonavian Dinosaurs Become Extinct?" Discovering Dinosaurs: Evolution, Extinction, and the Lessons of Prehistory. Berkeley: U of California, 1995. N. pag. Print.
Reptiles are vertebrate, or backboned animals constituting the class Reptilia and are characterized by a combination of features, none of which alone could separate all reptiles from all other animals.The characteristics of reptiles are numerous, therefore can not be explained in great detail in this report. In no special order, the characteristics of reptiles are: cold-bloodedness; the presence of lungs; direct development, without larval forms as in amphibians; a dry skin with scales but not feathers or hair; an amniote egg; internal fertilization; a three or four-chambered heart; two aortic arches (blood vessels) carrying blood from the heart to the body, unlike mammals and birds that only have one; a metanephric kidney; twelve pairs of cranial nerves; and skeletal features such as limbs with usually five clawed fingers or toes, at least two spinal bones associated with the pelvis, a single ball-and-socket connection at the head-neck joint instead of two, as in advanced amphibians and mammals, and an incomplete or complete partition along the roof of the mouth, separating the food and air passageways so that breathing can continue while food is being chewed. These and other traditional defining characteristics of reptiles have been subjected to considerable modification in recent times. The extinct flying reptiles, called pterosaurs or pterodactyls, are now thought to have been warm-blooded and covered with hair. Also, the dinosaurs are also now considered by many authorities to have been warm-blooded. The earliest known bird, archaeopteryx, is now regarded by many to have been a small dinosaur, despite its covering of feathers The extinct ancestors of the mammals, the therapsids, or mammallike reptiles, are also believed to have been warm-blooded and haired.