Essay 'Hello, Luca ', Last Universal Common Ancestor'

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

Cultural Diversity “Ancestors- The Genetic Source” and “Why My Mother can’t speak English” are two both entirely diverse cultural up in immigrants. In both stories there are similarities and differences. In both stories how people who migrated to Canada bring their language, beliefs and cultural background or tradition. In the story “Ancestors-

In this assignment I am going to be talking about a complex piece of work that I have already done for an assignment, and I will be explaining the value of 3 different resources and evaluating the 3 sources in terms of validity. The 3 resources that I am going to be talking about are: the internet, a text book, and NHS facts. I found all of these resources useful in different ways, and also reliable in different ways. I chose these particular resources because I have many opinions about them, some good, some bad. The

Introduce the second main point of the argument. Then, provide evidence from the sources. Multiple pieces of evidence should be provided to support the main point.

Often scientists work with bacteria that do not come in a labeled test tube— for example, bacterial samples taken from infected human tissue or from the soil—and the scientist must then identify the unknown microorganism in order to understand what behavior to expect from the organism, for example, a certain type of infection or antibiotic resistance. However, because of the relatively few forms of bacteria compared to animals and because of the lack of bacterial fossil records due to their asexually reproductive nature, the taxonomy used to classify animals cannot be applied to bacteria (Brown 275). In order to classify unknown bacteria, a variety of physiological and metabolic tests are available to narrow a sample down from the fathomless number of possibilities into a more manageable range. Once these tests have been performed, the researcher can consult Bergey’s Manual of Determinative Bacteriology, a systematically arranged and continually updated collection of all known bacteria based on their structure, metabolism, and other attributes.

Write one summary statement, one integrated direct quotation, and one paraphrase statement for each of your three sources, including parenthetical citations for each. An example has been completed for you.

Prior to the development of DNA technology and the sequencing of organismal genomes, Charles Darwin suggested that the “tree” of life can be traced back to a single root (Koonin and Wolf, 2012). While Darwin’s theory was primitive, it laid the groundwork for the phylogenetic trees that are currently studied in science classrooms around the world. The three-domain tree, containing Eukarya, Archea, and Bacteria, soon became too simplistic due to the realization that some bacteria possessed the ability to exchange genetic information by horizontal gene transfer (Koonin and Wolf, 2012).

There were two types of bacteria: sulfur-eating bacteria, and cyanobacteria. Sulfur eaters were the predominate kind of bacteria, but died out when cyanobacteria started photosynthesizing and producing oxygen. Oxygen is lethal to sulfur-eating bacteria. This was called the great oxygenation. The sugars produced by photosynthesis would be the base of the modern food chain. The origin of archaea is unknown. Eukaryotes came into play around 1.5 billion years ago.

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.

Discuss the validity of each one of your sources. Be sure to make comments regarding credibility, bias, timelines (when was your cited references written/updated?), and information content.

Researchers at Heinrich Heine University sought out characteristics of LUCA, which stands for the last universal common ancestor. They found, through gene family analysis, that LUCA was a microbe that lived when the Earth had little to no oxygen. In fact, its metabolism implies that it was an organism that thrived in higher than normal temperatures and consumed hydrogen gas. From this information, scientists predicted that an environment near hydrothermal vents would have allowed LUCA to become successful, as it provides the sources of hydrogen gas and heat. These findings were published in July of 2016 in Nature Microbiology (Service, 2016).

Darwin once hypothesized that humans evolved from an ape like ancestor and that those ancestors most likely originated in Africa since the majority of the great apes lived there. Unfortunately, Darwin’s hypothesis was ignored for reasons such as people (e.g. Europeans) not liking of having African ancestors—not to mention the lack of evidence did not help in supporting such hypothesis. Thus, finding the missing link between apes and humans was of great important—it still is. Thankfully, through extensive research many scientists have been able to determine a clade called Hominin [7]. This clade contains humans as well as their most closely related relatives.

During the 1980s, three specialists, Allan Wilson, Rebecca Cann and Mark Stoneking, worked together on another theory that supports Charles Darwin's speculation, the “Mitochondrial Eve” hypothesis. In these tests, the scientists solemnly focused on mitochondrial DNA, human genes that lay within the cell and are passed from mother to child. These genes allow mutation, as they mutate quickly for adaptation, thus allowing those studying to find and track changes during short time periods. By focusing on these genes and comparing their differences, the three scientists were able to create a hypothesis about the time and place when modern humans began to evolve. According to their findings, they believe that modern humans are decentants from a single population, while earlier humans e.g. Neandertals and Homo erectus, had become extinct. Furthermore, the team compared the DNA of numerous people of differerent ethnic backgrounds and concluded that all humans did indeed evolve from 'one mother' in Africa about 150,000 years ago.

Prokaryote cells - bacteria and archeans. They are single celled organisms, where the DNA is not separate from the cytoplasm. These prokaryote cells formed the earliest and most primitive life on earth.

2. Selection and reading of the sources to determine which ones are the most relevant and comprehensive 3. Finding opposing arguments to