Endosymbiosis is important as it enables us to understand the evolution of eukaryotes from the common ancestor. This essay will focus on: the early evolution of our eukaryote ancestor during Precambrian period, plastids origin along the algae family due to second endosymbiosis; discuss the evidence that supports the theory, including further examples of endosymbiosis.
The theory, as discussed by Lynn Margulis, states that mitochondria originated from α-proteobacteria bacterium which was engulfed by the ancestral anaerobic eukaryotic cell, through endocytosis, and retained within the cytoplasm due to atmospheric oxygen increase. Prokaryote organism produced ATP, through oxidative phosphorylation, by receiving organic compounds from the eukaryote, causing the eukaryote to become dependent on prokaryote for ATP production and the prokaryote to become dependent on the eukaryote for other cellular functions. Consequently, both organisms evolved in symbiosis with each other and most the genes of a unicellular organism were transferred to the genome of the host, getting enclosed in the nucleus. Due to the advantageous relationship between the host and symbiont, prokaryote organism lost their ability to survive independently and, was reduced into mitochondria which were transmitted to future generation vertically (Debashish et al., 2003). The evolutionary history of plants involves at least two independent endosymbiotic events (as shown in Figure 1); because plastids such as chloroplast evolved when a primary endosymbiotic event caused photosynthetic cyanobacteria to be engulfed by some non-photosynthetic host cells (Dyall et al., 2004).
Chlorophyta, Rhodophyta and Glaucophyta are three clades, belonging to the group Archaeplas...
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This lab was designed to determine the identity of “mystery spores” by growing them on an agar lined petri dish and observing them growing over the course. While their growth, we learned about various divisions within kingdom Plantae and their characteristics. Using this information about different divisions within kingdom Plantae and our observations of the mystery spores, we created a phylogenetic analysis comparing the mystery spores with the following divisions: Chlorophyta (green algae), Marchantiophyta (liverworts), Bryophyta (mosses), and Pteryophyta (ferns). According to this analysis, we concluded that the mystery spores belonged to the division Pteryophyta. 2.
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These results gave us a chi-square statistic of .06787 and with a degree of freedom of 1, this .06787 is below the critical value of .05 so therefore the results do follow typical patterns of inheritance. This means that our hypothesis for the monohybrid cross was correct, the F2 generation follows Mendelian inheritance patterns. In the dihybrid cross, the observed results were 487 or 55.7 % of the plants had anthocyanin dark green leaves, 166 or 19% of the plants had anthocyanin yellowish green leaves, 136 or 15.6% of the plants had no anthocyanin dark green leaves, and 85 or 9.7% of the plants had no anthocyanin yellowish green leaves. These results gave us a chi-square statistic of 21.703 and with the degrees of freedom at 3 this is still well below the critical value of .05 and therefore the dihybrid cross does not follow typical patterns of inheritance. This means that our hypothesis for the dihybrid cross was rejected, the F2 generation of Brassica rapa did not follow Mendelian inheritance patterns. The results show that the monohybrid cross did follow Mendelian inheritance patterns, while the dihybrid
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.
Thomas R. Warne, Leslie G. Hickok and Rodney J. Scott. (1988). Botanical Journal of the Linnean Society. Characterization and genetic analysis of antheridiogen-insensitive mutants in the fern Ceratopteris. 96 (1), 371-379.
ABSTRACT: Chloroplasts carry out photosynthetic processes to meet the metabolic demands of plant cells (Alberts, 2008). They consist of an inner thylakoid membrane and a stroma. (Parent et. al, 2008).In this experiment we demonstrate the unique protein compositions of isolated thylakoid and stromal fractions from broken and whole spinach chloroplasts. Because these compartments carry out different metabolic processes, we confirm our hypothesis that performing SDS-PAGE on these fractions will result in distinct patterns on the gels. In isolating and analyzing nucleic acid from broken, whole, and crude chloroplast samples we demonstrate that genes for photosynthetic protein psbA are found in chloroplast DNA, while genes for photosynthetic enzyme
Philip G. Fothergill, Historical Aspects of Organic Evolution, pub. 1953 by the Philosophical Library Inc., 15 East 40th Street, New York, NY
The mitochondria has an eggshape structure. The mitochondria consists of an inner and outer membrane. The outer membrane is what shapes the organelle to its egglike shape. The inner membrane which folds inward makes a set of "shelves" or cristae that allow the reactions of the mitochondria to take place. The more the mitochondria makes these reactions the more the inner membrane folds.
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.
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This organelle is the site of photosynthesis in plants and other organisms. In the structure, the chloroplasts has a double membrane, the outer membrane has a continuous boundary. This organelle can be found in a vast group of organelles called the plastid, chloroplasts are usually found in many plant cells but never in animal cells. Chloroplasts organelles are large; they are 4-10um long and 2-3um wide. They are very important to plants because chloroplasts are what plants use to create food from sunlight. Chloroplasts are not found in humans.
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