evolution 3
Evolution, a process of change through time, is what links together the enormous diversity of the living world. A lot of evidence is present that indicates that the earth has had a very long history and that all living things arose in the course of that history from earlier, more simpler forms. In other words, all species have descended from other species and all living things share common ancestors in the past. Basically, organisms are what they are because of their history. Today there are many theories and possibilities related to evolution which contribute to our understanding of the process. Our planet was born 4.6 billion years ago as a great cloud of dust and gas condensed into a sphere. As gravity pulled this great cloud tightly together, heat from great pressure and radioactivity melted the planet's interior and most of its mass. For millions of years after this, strong volcanic activity all over the planet shook the earth's crust. At the same time, the earth was showered by a very strong meteor shower. From studying volcanoes, it is known that eruptions pour out carbon dioxide, nitrogen, and other gases. It is also known that meteorites carry water, in the form of ice, and many carbon containing compounds. That might s
As for eukaryotic cells, according to Lynn Margulis's hypothesis, they arose from what is called a symbiont relationship. Lynn Margulis believed that mitochondra were originally independent prokaryotic aerobic individuals, living on a symbiont relationship with another prokaryote. The aerobic prokaryote was enclosed by the bacterium's cell surface membrane in the process of endocytosis, which is made easy by the absence of a cell wall in the bacterium. The aerobic prokaryote wasn't digested but continued to function inside the other cell. The host cell received energy that the aerobic prokaryote released. The mitochondrion that was forming had everything it wanted, taking it from its host. A similar process occurred later with the host cell and photosynthetic prokaryotes. This evidence explains the symbiotic theory for the origin of the four Eukaryotic kingdoms, which are the Protista, Fungi, Animalia, and Plantae. In 1858, Charles Darwin introduced a theory of evolution that is accepted by almost all scientists today. His theory states that all species evolved from a few common ancestors by natural selection. Another British scientist, Alfred Wallace, introduced an identical theory at about the same time. But Darwin's theory was better developed and more famous. Darwin's and Wallace's concept was based on five premises: 1) there is stability in the process of reproduction 2) in most species, the number of organisms that grow, survive, and reproduce is small compared to the number initially produced 3) in any population, there are variations that are not produced by the environment and some are inheritable 4) which individual will grow and reproduce and which will not are determined to a significant degree by the interaction between these chance variations and the environment 5) given enough time, natural selection leads to the accumulation of changes that differentiate groups of organism from another. 8. http://bioinfo.med.utoronto.ca/~lamoran/Evolution_home.shtml
Some common words found in the essay are:
DNA Eukaryotic, Earth Scientists, , Darwin's Wallace's, Revolution England, Miller Urey, Bruce Alberts, Jean Baptiste, Lynn Margulis, RNA DNA, natural selection, earth's atmosphere, tree trunks, amino acids, dark-colored moths, peppered moths, common ancestor, aerobic prokaryote, nucleic acids, darwin's theory, ancestors stretched necks, theory natural selection, darwin's theory natural, necks ancestors stretched, earth's atmosphere formed,
Approximate Word count = 2705
Approximate Pages = 11 (250 words per page double spaced)
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