Eukaryotic Cells are Deemed as a Result of the Evolution of Symbiotic Prokaryotes
Both Prokaryotic and Eukaryotic cells over time have sustained very
dynamic changes from one another. More specifically we have seen the
appearance of a more complicated and organized cell structure, the
nucleus. However the big question amongst scientists today is how did
these changes first occur? A fundamental concept of this evolution is
the belief in the natural progression 'from the simple, to the more
complex.' However one popular theory that argues that Prokaryotic
symbiosis was responsible for forming the Eukaryotic nucleus is the
'Endosymbiotic Theory' this theory was first proposed by a former
Boston University Biologist known as Lynn Margulis in the 1960's.
Although the theory was ridiculed by a number of mainstream
biologists, it now serves as a plausible and acceptable theory and
explanation to the evolution of Eukaryotes.
The theory states that the ancestors of eukaryotic cells were
"symbiotic consortiums" of their prokaryotic cells, with at least one
and possibly more species involved these were later known as
endosymbionts. To put this into light, a reasonable example could be
this: oxygen breathing bacteria invaded an anaerobic amoeba like
bacteria and each then performed mutually benefiting functions. They
would both end up helping each other greatly; the bacteria would
breathe for the anaerobic amoeba like bacteria and the amoeba like
bacteria would navigate through oxygen-rich waters in search of food.
This way both of the bacteria organisms would be benefiting from a
form of symbiosis. Other studies show that prior to the Cambrian
Explosion of Eukaryote Organisms the oxygen levels began to soar
immensely at about 2.5 billion years ago, followed by the first
nucleated cell 1.5 billion years ago.
Another important factor to this theory is one discovery made by a
professor Kwang Jeon of the University of Tennessee. In 987 he noticed
that his amoeba collection were developing large numbers of dots.
These dots later turned out to be a bacterial invasion, they began
killing of the professor's collection.
In her book, Dorothy Crawford gives biographies of the history of microbes which have brought humans diseases on a large scale. These include epidemics like yellow fever, tuberculosis, smallpox, acute respiratory syndrome, bubonic plague, syphilis HIV, the Black Death, malaria and cholera. It is worth to point out that her work is up to date because most of these microbes are still with us in this era. Crawford uses the historical bibliography of humans experience with microbes to show a fact that microbes shaped our culture through infection, disease, and pandemic. At the same time, the ever changing human culture has also largely influenced the evolutionary nature of microbes.
There are many different cells that do many different things. But all of these cells fall into two categories: prokaryotic and eukaryotic cells. Eukaryotic cells contain a nucleus and are larger in size than prokaryotic cells. Prokaryotic cells do not contain a nucleus, are smaller and simpler than eukaryotic cells. Two of their similarities are they both have DNA as their genetic material and are covered by a cell membrane. Two main differences between these two cells are age and structure. It is believed that prokaryotic cells were the first forms on earth. They are considered primitive and originated approximately 3.5 billion years ago. Eukaryotic cells have only been around for about a billion years. There is strong evidence that suggests eukaryotic cells may be evolved from groups of prokaryotic cells that became interdependent on each other (Phenotypic analysis. (n.d.).
The primordial Soup theory was discovered in 1920. According to the Russian scientist A.I. Oparin and English Geneticist J.B.S. Haldane life started in a warm pond/ocean in a process that took place 3.8 billion years ago. A combination of chemicals made fatty acids which made protein. In this process a molecule was born in the atmosphere. The molecule was energized with lightning and rain making “organic soup”. The first organisms would have to be simple heterotrophs in order to survive.
In contrast, eukaryotic organisms typically include (but are not limited to) membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum (E.R.), golgi body, lysosome and peroxisome. The main defining difference between a eukaryote and prokaryote is that the latter does not contain a nucleus or any such organelles. Such a definition, however, can be argued to be a poor discriminator between organisms of Eukarya and Prokarya, because it describes only what prokaryotes are lacking, not what they fundamentally are. This essay aims to detail a more comprehensive definition of why these two kingdoms are so different from each other. A key example of this thinking is that, while prokaryotes are often singly responsible for metabolic processes, reproduction and cell repair, eukaryotes are often highly specialised in order to perform certain functions and rely upon other cells to fulfil different functions. For exa...
The Precambrian Era is when the Earth formed. Earth was barley a spec of dust in outer space and as time went by it gathered ice, rock and more dust particles. It eventually formed into a big rock flying around in space. The Earth was extremely hot and so when it rained the rain would evaporate in mid air or immediately after it hit the ground. But even though it evaporated these great rains cooled the Earth eventually building up water in lower areas creating oceans. The Earths atmosphere was water vapor, carbon dioxide, nitrogen and gases. After awhile oxygen level grew in the atmosphere. The earliest life forms were single celled organisms that lived in the oceans. These organisms used light energy to produce food called photosynthesis. These were called Prokaryotes and Eukaryotes. The evolution of multi celled organisms were Dramatic in change.
Eukaryotic cells, whether from animals, plants, protists, or fungi, are the most structurally advanced of the major cell types. Eukaryote are single-celled or multicellular organism whose cells contain nucleus and any other structures (organelles) enclosed within the membrane that perform specific functions. The surface of the cell is covered with a thin film or plasma membrane, which is the boundary that separates the living cell from its nonliving surroundings. Plasma membranes are composed mostly of proteins and lipids (Simon, 02/2012, p. 59-60).
Since the beginning billions of years ago when God reached down and fused the base elements of life into a single-cell organism, that's how long this process has been taking place. As the amoeba of life spread to different parts of a world that was just beginning to take shape, it encountered different challenges for survival, the cells that couldn't survive died and the one or two mutated cells that could survive continued, multiplying and dominating each particular environment.
...hemical energy from cyanobacteria (the only bacteria that can perform photosynthesis) 2.4 billion years ago (Wernergreen). The first chloroplast came into being about one billion years ago when a single-celled protist and a cyanobacterium came together through endosymbiosis, and this first photosynthesizing eukaryotic lineage was the ancestor of land plants, green algae, and red algae. Cyanobacteria and algae endosymbionts have spread photosynthetic capabilities in such a broad range (Wernergreen). In other words, heterotrophic prokaryote cells had taken in autotrophic photosynthetic bacteria cells. The ingested cell continued to provide glucose and oxygen by photosynthesis. The host cell protected as well as provided carbon dioxide and nitrogen for the engulfed cell and overtime both cells lost the aptitude to survive without each other (Weber and Osteryoung).
According to the theory of evolution, approximately 3.8 billion years ago some chemicals accidentally structured themselves into a self-replicating molecule. This beginning spark of life was the ancestor of every living thing we see today. Through the processes of mutation and natural selection, that simplest life form, has been shaped into every living species.
The nucleus is one of the most important organelles in a eukaryotic cell. The shape of the nucleus is generally spherical, it should be oval, disc formed reckoning on the sort of cell. The nucleus was found by Robert Brown in 1831 while he was looking at orchids under a microscope. He discovered a blurred area in the cells of the flowers and called it the areola or the nucleus.
The Cambrian explosion is challenging for biologists to interpret because it poses a problem that it seems to be inconsistent with the understood gradual pace of evolutionary change. Even though there is this major difference from this occurrence compared to the ‘normal’ evolutionary model, it doesn’t mean it cannot happen. There has been o...
According to scientists, one of the most extraordinary bursts of evolution ever known was the Cambrian Explosion. For most of the nearly 4 billion years that life has existed on Earth, evolution produced little beyond bacteria, plankton, and multi-celled algae. Then, about between 570 and 530 million years ago, another burst of diversification occurred. This stunning period is termed the "Cambrian explosion," taking the name of the geological age in which the earlier part occurred. A recent study revealed that life evolved during the Cambrian Period at a rate about five times faster than today. But it was certainly not as rapid as an explosion; the changes seems to have taken around 30 million years, and some stages took 5 to 10 million years. The Cambrian explosion was a period of time where life evolved into numerous multifaceted organisms that developed into the vertebrates and human life as we know today.
"Photorhabdus and Xenorhabdus bacteria colonize the intestines of the infective soil-dwelling stage of entomophagous nematodes, Heterorhabditis and Steinernema, respectively. These nematodes infect susceptible insect larvae and release the bacteria into the insect blood. The bacteria kill the insect larvae and convert the cadaver into a food source suitable for nematode growth and development. After several rounds of reproduction the nematodes are recolonized by the bacteria before emerging from the insect cadaver into the soil to search for a new host.
The membrane surrounding the nucleus in eukaryotic cells, separate the nucleus from the cytoplasm. Most of the cells we used in the experiments held, were multicellular or consisting of more than one cell. A variety of cells were used in completing the experiments. We used union cells, cheek cells, potato cells, and Elodeo cells. We also used Planaria which is a unicellular organism.
Prokaryotic cells do not have a nucleus. The chromosomes which are found in prokaryotes are usually spread in the cytoplasm. In eukaryotic cells the chromosomes remain together inside the nucleus and there is a clear nuclear membrane that is surrounding the nucleus.