What Is The Earliest Evidence For Life On Earth?
Life on earth has been in existence since time immemorial based on plenty of evidences that are presented by scientists who in many occasions have devoted their energy to study about life on earth. Research done by most scientists indicate that the presence of life on earth is as old as man himself while others scientific studies suggest that life was not present so long. The presence of fossils is enough to prove the already existing evidence including some other organism bodies that are preserved in historic sites. Secondly, the planet atmosphere has been changing from time to time and this has had various impacts on the way of life. Every aspect should therefore put in consideration so as to make every study relating to astronomy to be completed management.
Plenty of records presented by scientists are a sure prove for existence of life on earth. Discovering of fossil records is among the simplest ways utilized by scientists in their quest to collect proof regarding life existence on earth. It is normal for fossils to form on sedimentary rocks which are found beneath water body bed. Fewer organisms are conserved in the sediments when the organisms’’ body decays prior to fossils inside the sedimentary rocks (Xu et al. 2017). At times, the organisms are formed on the rocks making it easy for the scientists to acquire the organisms’’ complete bodies. Still however, some or the organisms may fail to be conserved in the sediments. In this case, scientists will have to gather bones and shells of the organisms which help in the understanding of traces of presence of life on earth.
Dodd et al. (2017) suggest that finding fossils of organisms that exited long ago is a difficult task for most scientists. Studies have indicated that the Cambrian Period witnessed little to no organisms with shells and bones and so soft organisms could not form fossils. Very few fossils of organisms that lived in the period above are found by scientists the reason being that most organisms of the said period were in microbial form. Another reason that has proved difficult for scientists to find fossils is the recycling process that convert parts of organisms into other forms. Decomposition of the earth which occurs unceasingly deforms the plates making it difficult to comprehend the era in which the organism in question was in existence.
Stromatolites As Evidence Of Life
The Dilemma exhibited by Darwin was an obstacle in finding the fossils prior to the Cambrian Period. It was not easy to find fossils given that fossils were not available throughout the pre-Cambrian Period. Lack of important remains simply suggests that organisms were not present in periods before that Cambrian Period. The year 1965 saw two experts who stated categorically that they had discovered fossils that were more than two billion years (Caro, Morino, Mojzsis, Cates and Bleeker, 2017). The fossils were discovered at the Gunflint Chart that is adjacent to Lake Superior. The 2 fossils existed in form of microfossils and stromatolites of the original organisms. Later, other scientists also discovered remains of organisms that had been in existence for more than 3.5 billion years. The fossils that were 3.5 billion years proved that the life was on earth even in the Pre-Cambrian Period.
Stromatolites are the kind of structures developed in form of layers by micro-organisms’ colonies. Stromatolites are formed over the layers of the rocks when various organisms are cemented together. They are not found in other places but in shallow water bodies. One of the earth’s places where stromatolites are present in plenty is the Shark Bay in Western Australia. Some of these structures have gone missing while others only present themselves in hyper saline waters. Scientists with the mission of studying Stromatolites have founded out that they are frequently located in the Archean and Proterozoic periods hence looking for these structures in the prior to the Archean and Proterozoic will prove difficult. Some scientists believe stromatolites are not biological creatures and they can be categorized as part of life (Caro, Morino, Mojzsis, Cates and Bleeker, 2017). They are also certain that stromatolites are seen only in association with microfossils making them to be part and parcel of the biological creation.
History has it that the presence for life on earth is somewhat controversial. Conflicting opinions from scientists in regard to the presence of life before billions or say millions of years is another factual problem to the situation. Many fossils are stated to be dating back to as early as 3.5 billion years but still scientists have different opinions over this fact. A statement from one of the scientists by the name Bill Schopf proves that 3.5 billion years ago microbial life had just kicked off arguing that such fossils would have been extensive at that period of time (Huang, Chen, Wignall and Zhao, 2017). Another scientists by the name Martin Brasier argues that that is no evidence as the ones discovered are not fossils as they are formed by reactions between volcanic glass and vein chart. The rock of Pilbara has stromatolites that are as old as 3.43 billion years and according to studies, they are the oldest form of all stromatolites found on earth. These stromatolites are found deep in the water are assumed to be stromatolites of reef.
Geological Periods And The Presence Of Life
Wilhelm et al. (2017) observes that studies based on geological periods are other ways under which we can understand the presence of life for the earth. The layers found of the rocks communicate more about the era making researchers to appreciate that different organisms existed in various eras. Studying of rocks also make scientists to comprehend the era by which particular organisms were surviving. Geological studies are not new in the life of man and therefore, scientists can still obtain fossils that date back to even 550 million years back. Geological studies also suggest that life on earth has existed for not less than 4 billion years.
Another type of life is the molecular record of life which seeks to understand life existence on other. Usually, the molecular record of life studies the molecules present in the organisms DNA, where the organism DNA is related in order to make a comparison of the two DNAs to help in the understanding of life by the scientist (Sutherland, 2017). Following the comparison of the human and chimpanzee DNAs to a scale of 100%, it was founded that 98 % their DNA matched making scientists to believe that the two organisms are interrelated. Insufficient genes are communal for a greater part of life on earth and so it is widely concluded that many of the organisms are developed by way of translation, transcription, and replication of the contemporary DNA.
Life on earth can be described by the help of the tree of life which positions life into three different fields: Archaea, Eukarya, and Bacteria where the whole DNA concept is founded on this tree. The avid research conducted by various scientists suggested the tree of life consists of not just three but five domains, however, fungi, plants, and animals was placed in the Eukarya kingdom (Biswas, Shome, Raha and Bhattacharya, 2017). The earth branches consisting of Archaea and Bacteria are small and simple cells. When this form of life was narrowed down to specificity, Eukarya was broadly considered. The Eukarya cells are large and complex Nursing they contain nucleus plus other important structures.
Endosymbiosis is the process by which eukaryotic cells are generated. Another process called Endomsymbiosis refers to the symbiotic relationship by which an organism exists in the body of another organism. Organelles found in eukaryotes are in line with symbiotic relationship with the eukaryote antecedent. Another form of life evident on earth to have been there for billions of years is the chloroplast which enables the process of photosynthesis to take place (Gale and Wandel, 2017). Chloroplasts are the new form of ancient cyanobacteria which evolved as a result of photosynthesis process which occurred billions of years back. It is also believed that chloroplasts originates based on the symbiotic relationship with the ancestor cells. The symbiotic relationship of chloroplasts and their ancestor cells is seen when the DNA is observed.
Molecular Record Of Life
There are a lot of evidences that are presented in fossil forms and few organisms bodies to prove the existence of life on earth. Some of the evidences were not conserved due to bad weather. More still, the planet atmosphere has been changing from time to time and this has had various impacts on the way of life. Not many organisms are preserved in sediments given that their bodies degenerate before fossils are formed in sedimentary rocks. The year 1965 saw two experts who stated categorically that they had discovered fossils that were more than two billion years. The fossils were discovered at the Gunflint Chart that is adjacent to Lake Superior. The 2 fossils existed in form of microfossils and stromatolites of the original organisms. Conflicting opinions from scientists in regard to the presence of life before billions or say millions of years is another factual problem to the situation. However, all studies done by different scientists generally approve that life on earth has been in existence for long period of time in as long as organisms have lived on earth. Enough evidence is availed to make us believe that earth has witnessed various forms of life and so life on earth is not a new phenomenon.
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