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Embryological development of tooth
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Transitions of Reptiles to Mammals
A long long time ago, in a galaxy not too far away, was a little blue planet called Earth, and on this world not a single mammal lived. However a lot of time has past since then and we now have lots of furry creatures that are collectively called mammals. How did they get their? Where did they come from?
These are the kinds of questions that led me to my subject of choice. I will endeavor to provide examples, using specific transitional fossils, to show that mammals have evolved from a group of reptiles and were simply not placed here by unknown forces.
Before I begin, I would like to define some terms so that nobody gets left in the dust. The term transitional fossil can be used in conjunction with the term general lineage, together they help explain the how one species became another. "General lineage":
This is a sequence of similar genera or families, linking an older to a very different younger group. Each step in the sequence consists of some fossils that represent certain genus or family, and the whole sequence often covers a span of tens of millions of years. A lineage like this shows obvious intermediates for every major structural change, and the fossils occur roughly (but often not exactly) in the expected order. However, usually there are still gaps between each of the groups. Sometimes the individual specimens are not thought to be directly ancestral to the next-youngest fossils (e.g. they may be "cousins"" or
"uncles" rather than "parents"). However they are assumed to be closely related to the actual ancestor, since the have similar intermediate characteristics.
Where Does It All Begin ?
Mammals were derived during the Triassic Period ((from 245 to 208 million years ago) It began with relatively warm and wet conditions, but as it progressed conditions became increasingly hot and dry.) from members of the reptilian order Therapsida. The therapsids, members of the subclass Synapsida
(sometimes called the mammal-like reptiles),generally were unimpressive in relation to other reptiles of their time. Synapsids were present in the
Carboniferous Period (about 280 to 345 million years ago) and are one of the earliest known reptilian groups. Although therapsids were primarily p...
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...ng the origin of major new adaptive types. To simplify definitions and to allow the strict delimitation of the Mammalia, some authors have suggested basing the boundary on a single character, the articulation of the jaw between the dentary and squamosal bones and the attendent movement of accessory jaw bones to the middle ear as auditory ossicles. The use of a single character allows the placement in a logical classification of numerous fossil species, other mammalian. characters of which, such as the degree of endothermy and nursing of young and the condition of the internal organs, probably never will be evaluated. It must be recognized, however, that if the advanced therapsids were alive today, taxonomists would be hard-put to decide which to place in the
Reptilia and which in the Mammalia.
References
Carroll, R. 1988. Vertebrate Paleontology and Evolution. W.H. Freeman and
Co., New York
Gingerich, P.D. 1977. Patterns of Evolution in the Mammalian Fossil Record.
Elsevier Scientific Pub. Co.
Gingerich, P.D. 1985. Species in the Fossil Record: Concepts, Trends, and
Transitions. Paleobiology.
Rowe, T. 1988. Definition, Diagnosis, and Origin of Mammalia. J. Vert.
Paleontology.
Once altered, the baby will have no say in how its cells are used, or traits they wish to keep but no longer will have the chance too. Some designer babies are created to help others through transplants. Even though the intention may be decent, it is still taking away the child's chance to have a choice in his body. Certain transplants are painful, such as a bone marrow transplant, and creating the child to be used as a donor could possibly put him through involuntary pain.
: Primates didn’t just appear among Earth, but they evolved. The coevolution has to do with flowers and fruits. Fruits were evolving to get tastier for primates to eat and as primates ate them they spread them around as well. As they ate these new evolved fruits and flowers this invited changes onto their bodies as
Mountain building and climate changes happened often in this period, as well as the breakup of Pangaea. Mammals were very popular and they were very different and everywhere. The climate was much colder now. The animals adapted to their environment and diets; meat eaters had sharp teeth for cutting and ripping, rodents had self-sharpening front teeth for gnawing and plant eaters had molars for grazing plants.
What do one think of when they hear the words “Designer Babies”? A couple designing their own baby of course, and it’s become just that. Technology has made it possible for there to be a way for doctors to modify a babies characteristics and its health. Genetically altering human embryos is morally wrong, and can cause a disservice to the parents and the child its effecting.
could either survive through adaptation or die off due to an inability to adapt rapidly enough. All different types of animals, carnivorous and herbivorous mammals, birds, and reptiles, lived during the Pleistocene epoch and thanks to preservations such as the La Brea tar pits, we are able to observe and study the life forms of millions of years ago.
How far is society willing to advance genetic enhancement technology before it becomes a moral wrong? Medical technology is well on the way to allowing parents to create designer babies, permitting parents to pick physical and internal qualities of unborn children. Due to the advance in technology allowing parents to genetically designer their own child, The American Medical Association (AMA) should create stronger codes of medical ethics and acts imposing limitations. The manipulating with embryos in order to create a parent’s ideal child is morally wrong, and should be against codes of ethics. In order to create a fine line between enhancement that prevents disease and birth defects, and the self-absorbed society that prefers children with little to no flaws; laws of ethics in medical practice need to be implemented. Therefore, with distinguished lines on medical ethics, society will not become divided and unrecognizable due to genetically enhanced humans.
... tested hairs and other parts for DNA and concluded that they fit into our family tree. “ Those hair samples that could not be identified as known animal or human were subsequently screened using DNA testing, beginning with sequencing of mitochondrial DNA followed by sequencing nuclear DNA to determine where these individuals fit in the tree of life” (Ketchum 2013).
Those were the many questions I had at the beginning of my search. I planned
There is great debate over the concept of primate evolution. Some research supports the idea that evolution occurred linearly as a continuum while other research supports the idea that fossils found to date should be separated into individual species. Through morphological, and geological evidence this paper explores this topic and provides concise arguments to further develop the understanding of human primate evolution.
Imagine a parent walking into what looks like a conference room. A sheet of paper waits on a table with numerous questions many people wish they had control over. Options such as hair color, skin color, personality traits and other physical appearances are mapped out across the page. When the questions are filled out, a baby appears as he or she was described moments before. The baby is the picture of health, and looks perfect in every way. This scenario seems only to exist in a dream, however, the option to design a child has already become a reality in the near future. Parents may approach a similar scenario every day in the future as if choosing a child’s characteristics were a normal way of life. The use of genetic engineering should not give parents the choice to design their child because of the act of humans belittling and “playing” God, the ethics involved in interfering with human lives, and the dangers of manipulating human genes.
living on earth disappeared. So how did these dominant creatures just die off? Was it a
...w after the fur trade it's taken them about 200 years to slowly repopulate. They are
Ethical considerations into the designer babies’ debate are placed on the basis of the effects that the procedure will have on the baby and the society. Families who are able to afford these procedures are few, and this will increase the disparity between the social classes (Ronald, 2007). Further, there will be an effect on the assortment of the gene pool as well as human genetics, which may lead to a...
== = = Human beings are dependent on the Earth's diversity of species for our survival. Wild species play a vital role in the maintenance of the planets ecological functions, yet everyday on the planet 40-100 species become extinct.
The media has promoted a dominant view of how people should perceive beauty, and what consists of perfection in beauty. According to Dr. Karin Jasper, the media have women encouraging them to be concerned with their outward appearance and how others perceive them by surrounding everyone with the ideal female beauty. (Jasper, 2000) Body image has become a particular concern for young girls and women, often females work diligently to attain the perfect body image advertised in mass media. (Gibbs, 2010) When women are not able to obtain their ideal body goal, many develop negative feelings and become self-conscious about their bodies. Conversely, it is not possible for someone to look like a model in ads, someone without blemishes, scars, or pours. Another study conducted in 2012 showed contemporary media and culture has defined a women’s social desirability in terms of their bodies. For females, this has often resulted in comparing themselves to bodies shown in advertisements, commercials, magazines, etc. however not all body