Revision of Biological Theories - Essay Example

1 A) Criticism and the revision of theories Criticism is always influenced by competitors who are willing to be more prominent than you are as a result they must scrutinize any activity that is presented by you. As this will be the first step of ruining your fame and your views to certain area. For instance as seen from the various researches done on evolution of cells by different scientists each research is trying to elaborate himself by really looking in the weakness of the opponent as the weakness from you will be used as the improvement of the other. However, with criticism many theories can be revised in order to clearly give out the exact nature. Through criticism, scientists are able to conduct more research on the evolution of and this will lead to more elaborate and clear understanding of the collect evolution. This can be clearly be seen from the research that lead to the understanding evolution of prokaryotic and eukaryotic as Marguli always needed to prove the reality behind the growth of Flagella as opposed by most of the scientists at the start. Piecemeal acceptance of new theories The piecemeal acceptance of the new theories was because of unclear defined evidences to the growth of the cell evolution. But the piece to piece acceptance also was contributed by criticizing scientists .For instance ,Marguli’s first book in 1970 on endosymbiosis although new to most of the scientist those who knew of it dismissed it making her to carefully again distinguish her ideas clearly from others like Ivan Wallin who first wrote of it. Resolution of scientific controversies. The only way to resolve a problem between two parties is by producing clear and substantial evidence that is used to oversee the evidence of the other. Controversial theories on the evolution between Marguli and other scientists for instance, her presenting a wide would only solve the close competitive theory by F.J.R Taylor and well explained with touchable evidence on the evolution of the cells like Prokaryotic and eukaryotic, mitochondria, chloroplast and flagella. Interrelationships of different scientific disciplines Through the scientific research of Margulis cell biology and evolutionary biology that previously seemed to have little in common now share most of the important and unifying theories. 2 Due to the criticism and dismissal of her scientific theory. Margulis was encouraged to clearly do research in order to fully gain acceptance on the cell evolution theory. Thus, she based her cell evolution on the past study of Ivan Walliam .As a result, by the end of a decade after his first book on 1970 she came up with analogies that were greatly accepted worldwide. She ended up gaining popularity on the Set theory than the autogency theory that emphasized on the end symbiosis. For instance Margulis in her Set theory she confirmed that few intermediates between prokaryotic and eukaryotic cells should be found against the autogeny which states that the eukaryotic cells developed gradually ,as research clearly shows quite sharps dividing lines between prokaryotic and eukaryotic cells against the support by the autogeny with evidence of many fossils of unicellular organisms. Margulis defined that a protein synthesis ribosomes in the mitochondria and chloroplast are much smaller than those in eukaryotic cells, but can be of the same size of ribosome in free-living bacteria. She observed the some of the antibiotics interfere with protein synthesis in the bacteria also influence the functioning of chloroplast and mitochondria but does not inhibit protein synthesis in the rest of the eukaryotic. No matter the piecemeal acceptance of the theories, most skeptical biologists accepted that mitochondria and chloroplast developed from bacteria. 3) Margulis believed that endosymbiosis was because of aerobic environment due to the existence of the aerobic bacteria and the development of eukaryotic cells that influenced the growth o the cells. Initially biologists took DNA in the cytoplasm unserious but after the research, she realized that the DNA in the cytoplasm contributed more to the development of many cells and the evolution of many cells. According to the traditional biologists, evolution occurs gradually centrally to SET theory that evolution is based on the idea of rather sudden evolutionary changes. This is well explained by the several intermediary links between the prokaryotic and eukaryotic cells. Evolution as per Marguli, s is through evolutional changes .She believes that first organisms evolved from a simple droplets of water that contained some genes and enzymes that later fed on organic molecule. As a result the prokaryotic cells then extracted energy from the molecules by fermentation that later led to the development of new particles that broke down the particles to oxygen later sustain the eukaryotic cells that are capable of using oxygen. The incorrectiveness of the theory can advance affect the scientific acceptance of the theory in that almost all of the theories in the research are based on endosymbiosis a. She only believed that evolution was achieved through evolutional changes. Thus, any misreading or misunderstood information will lead to the nullification of the theory, as it will be seen to have no concrete support to the evolution of the cells. 4. a) Half a century earlier Wallian had pointed out that mitochondria and chloroplast reproduce by dividing, as bacteria do but due to the in availability of modern material, he would not identify the DNA molecules. As per Taylor there was a central nucleiod where most of the genes are located although some several loops of DNA were also available this was seen as an assumption because some molecules of DNA are common among bacteria today. b) The earliest prokaryotic fossils from about 3.5 lead to the development of the eukaryotic cells. SET theory argues that eukaryotic cells evolved through a series of symbiotic partnerships of many prokaryotic cells of different kinds. Larger host cells were invaded by smaller partners and eventually evolved into mitochondria, chloroplasts, and flagella. The prokaryotic cells developed from simple microscopic droplets of water later the cells started emitting energy and oxygen that lead to development of eukaryotic cells c) Both organelles contain the membrane to provide large surface area for the attachment of other organelles as suggested by Margulis. d) From the SET theory is support for presence mitochondria and chloroplast in the cytoplasm and the evolution of eukaryotic cells. Early prokaryotic produced extracted energy by fermentation .other types of bacteria evolved as the supply of energy depleted and used solar energy to synthesize their own supplies their own organic molecules. A new group of photosynthesis evolved that split water to produce the Hydrogen ions and produced oxygen as a byproduct different to that, which was anaerobic e) Eukaryotic ribosome’s are smaller than for both chloroplast and mitochondria due to high protein requirement by the two organelles for the production of energy. f) Chloroplast and mitochondria are almost of the same size but differ as they evolve from in cooperation of many cells. g) Cyanobacteria live in the eukaryotic organism due to the presence of oxygen produced by the cells. h) Mitochondria and chloroplast are incapable of independent existence Mitochondria perform the function of cellular respiration it turns breaks down nutrients to provide energy and then chloroplast converts the energy into sugar and in the process oxygen is produced which is essential in photosynthesis. i) Both organelles use a proton _motive force and similar protein; they grow by in cooperation of lipids and proteins. j) Cyanobacteria are microscopic and use phycoyanin in photosynthesis, compared o chloroplasts that contain more defined chlorophyll that perform the photosynthesis. k) The chloroplast and mitochondria organelles do not replicate while cells do .for instance mitochondria has its own replication cycle. l)as from the SET theory chloroplast help in photosynthesis that help in breaking down water particles to produce oxygen that sustain most cell functioning. m) Controversial claim made by Margulis that eukaryotic flagella evolved from bacteria called spirochetes .the bacteria act like parasites and some live freely in exotic environment, hence they are attached to the plasma membrane and Margulis suggest that sometimes act like flagella since she claims they swim with an undulating motion. N) SET theory well explained that antibiotics that affected the protein synthesis also had an effect of eukaryotic cells which is it not so to cytoplasm ribosome’s due to the DNA structure in the cytoplasm. Read More