Prokaryotes Evolution

When life arose on Earth about 4 billion years ago, the first types of cells to evolve were prokaryotic cells. For approximately 2 billion years, prokaryotic-type cells were the only form of life on Earth. The oldest known sedimentary rocks found in Greenland are about 3.8 billion years old. The oldest known fossils are prokaryotic cells, 3.5 billion years in age, found in Western Australia and South Africa. The nature of these fossils, and the chemical composition of the rocks in which they are found, indicates that these first cells made use of simple chemical reactions to produce energy for their metabolism and growth. Eukaryotic cells evolved into being between 1.5 and 2 billion years ago. Eukaryotic cells appear to have arisen from prokaryotic cells, specifically out of the archaea. Indeed, there are many similarities in molecular biology of contemporary archaea and eukaryotes. However, the origin of the eukaryotic organelles, specifically chloroplasts and mitochondria, is explained by evolutionary associations between primitive nucleated cells and certain respiratory and photosynthetic bacteria, which led to the development of these organelles and the associated explosion of eukaryotic diversity. Today Prokaryotes

The purpose of this study is to identify four unknown organisms. The unknown organisms have been assigned randomly to six-research groups by Professor Hoffman. Each research group was provided two eukaryotes and two prokaryotes. The unknown organisms will fall into the following classifications: bacteria, algae, fungi, or protozoans. All living organisms are organized into one of three domains of life, Bacteria, Archaea, and Eukarya.

The identification of bacteria is a fundamental objective of microbiologists. It is essential to distinguish specific bacterial properties to understand the environment, physiology and disease. As new bacterial species emerge and existing ones evolve into different strains, it is imperative that microbiologists continue to isolate bacteria from the field, identify their findings and research newly discovered forms. Their discoveries can then be used to evaluate the types of microbial life that may be found in certain environments and the corresponding benefits or risks to those that dwell in those areas.

When we speak of the word “bacteria” some individuals may not recognize how large of a role these tiny organisms play in our everyday lives. Some may jump to the conclusion that bacteria are related to the spread of germs or sickness among the human population. Most microbes are harmless or beneficial (Matthews, 2015) and a large majority of these tiny microbes are extremely important in order to maintain the balance of living organisms and chemicals in our environment (Tortora, Funke, & Case, 2013).

Not too long ago, brilliant scientific pioneer, microbiologist and biophysicist Carl Woese presented his groundbreaking find that would revolutionize the scientific world. He and his partners discovered the kingdom consisting of single-celled organisms, which is today referred to Archaea. Thanks to Woese’s discovery, we now classify living organisms in three domains, Archaea, Bacteria, and Eukarya. Before Woese’s breakthrough, we did not realize how common and important Archaea actually are. Woese specialized in working with ribosomal DNA, which is how he uncovered Archaea. Eugene V. Koonin expresses deep admiration and praise towards Woese in his article. However, Koonin repeatedly judges Woese’s analysis on the evolution of cells as inexact and too general for legitimacy.

In the year 1665 an English scientist, Robert Hooke built the microscope and observed slices of cork and came up with the name cells to describe the arrangement of small box spaces within the cork. It wasn’t until Anton van Leeuwenhoek, that observed living organisms under a microscope, which he built and had a power of 300X. Leeuwenhoek was amazed by the fact of being able to view “animalcules”; he would sab a sample of water making people sick and samples of his own mouth. Over the years he would have viewed all the major organisms of microbiology, such as; protozoa, algae, yeast, fungi and bacteria in spherical, rod and spiral shapes. Leeuwenhoek did not sell his microscope or foster the development/ study of microbiology It was not until the later scientists who discovered the germ theory(Theodor Schwann), Redi,

However, due to their abundant added astronomically immense size, eukaryotes ' aggregate all-comprehensive biomass is estimated at about commensurable to that of prokaryotes. Eukaryotes aboriginal developed about 1.6–2.1 billion years ago.

Endosymbiosis is a compelling theory to the evolution of eukaryotic cells. As seen in the past with records of types of organisms that lived during a certain time period it can be seen that only bacteria that were prokaryotic existed. However later on eukaryotic cells with mitochondria or chloroplast cells were seen in nature. Back then the theory was not as widely accepted as is it today, but in recent years with the use of better technology examples of endosymbiosis has been discovered. An example of this would be the endosymbiosis that occurred in a lab by microbiologist Kwang Jeon. He had been studying amoebae when they were plagued by x-bacteria. This bacteria inserted itself into the cells causing a large quantity of the community to

Since the establishment of the basic concept of classification of organisms by Carl Linnaeus (Encyclopaedia Britannica) and Charles Darwin’s theory of evolution, various ideas and concepts have been suggested. After being repeatedly reviewed by a number of experts, some of them are accepted and this has enabled scientists to classify organisms, to recognise the connections between them despite of different physical appearance and to improve the understanding of evolutionary relationship between them. However, as time goes by and technology develops, the unknown aspects of organisms are being discovered and it arises several controversial points regarding the concepts and the principle of taxonomy. This essay will address one of those controversies, the validity of the concept of prokaryotes.

Bacterial toxin-antitoxin [TA] system are found throughout the prokaryotic kingdom (Cook et al. 2013; Bertram & Schuster 2014). The TA system plays a very important role in stress conditions that prevail in environments unfavorable for growth, for ex. amino acid starvation, higher/lower temperatures, pH, oxidative stress, etc. (Yamaguchi et al. 2011; Van Melderen & Saavedra De Bast 2009). TA systems are not essential for general bacterial growth. However, the bacterium continuously produces them investing a lot of energy. They are bicistronic elements that encode i) A toxin: A protein that negatively interferes with vital cellular functions in bacteria and ii) An antitoxin : A protein or an RNA molecule that keeps this toxin in check (Goeders & Van Melderen 2013). Both toxin and antitoxin are produced together however, toxin is more stable than antitoxin. Antitoxin therefore, is produced continuously to keep the effect of toxin in check (Gerdes & Maisonneuve 2012; Park et al. 2013). The toxin is known to effect bacterial functioning at variety of actions like cleaving DNA (Kunin & Ouzounis 2003; Pandey & Gerdes 2005) and RNA (Muñoz-Gómez et al. 2004; Yamaguchi & Inouye 2009), inhibition of ATP synthesis (Unoson & Wagner 2008), phosphorylation of proteins(Schumacher et al. 2009), etc.

For over two decades, amplification and sequencing of the small subunit ribosomal RNA (SSU rRNA or 16S rRNA) gene has been the primary approach to assess the abundance and taxonomic identity of microbes in the

“Discuss the origin and significance of diversity within and between species using examples from a named Eukaryote taxonomic group of your choice.”

In the 1930s the Dutch botanist Baas-Becking described microbial diversity as ‘everything is everywhere, the environment selects’. Up until recent times this statement has been taken to be fundamentally correct and is supported by authors such as Finlay (2002). However criticisms exist over Finlay’s conclusion, as he reasons that the global diversity of protozoa has been established, which is disputed by Foissner (2006). That accuses Finlay of not seeing the whole

The above diagram shows a prokaryotic cell. These cells have a simple cell structure and are thought to have been the first cells to have appeared on earth (Clark, 1998). Most prokaryotic cells are single-celled and none are found in living animals, it is mainly bacteria or algae that it is found in. The chemicals and enzymes are contained in the cytoplasm and are used for the cells growth. The cytoplasm is a jellylike mixture that is packaged into the membrane that forms the cell boundary. This cell does not contain a nucleus. The DNA is also attached to the plasma membrane.

Researchers over the past few decades have made it evident that microbial communities affect all species. I got an opportunity to broaden my horizon on this subject during my undergraduate studies at Calcutta University which covered three years of extensive material in Botany, Zoology, and Chemistry. I was intrigued with those interdisciplinary subjects which required a cogent and rational understanding. However, Microbiology fascinated me the most. I believe it to be a sub-discipline that explores the presence of a parallel world of organisms that has co-evolved with an excellent mechanism of survival. They affect our health, development, and the environment we live