Answer: The first piece of evidence that needed to be found to support the endosymbiotic hypothesis was whether or not mitochondria and chloroplasts have their own DNA and if this DNA is similar to bacterial DNA. This was later proven to be true for DNA, RNA, ribosomes, chlorophyll (for chloroplasts), and protein synthesis. The second piece of evidence is the person who proposed the endosymbiotic theory, or sybiogenesis, which is an evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms, first articulated in 1905 and 1910 by the Russian botanist Konstantin Mereschkowski and advanced and substantiated with micro biological evidence by Lynn Margulis in 1967. The third piece of evidence is the endosymbiotic hypothesis which concerns the origin of mitochondria and chloroplasts; two organelles contained within various eukaryotic cells. According to this hypothesis, these organelles originated as separate prokaryotic organisms that were taken inside a primordial eukaryotic cell.
Explanation: This article is by Heather Scoville. The endosymbiotic theory is the accepted mechanism for how eukaryotic cells evolved from prokaryotic cells. It involves a cooperative relationship between two cells which allow both to survive and eventually led to the development of all life on earth. The endosymbiotic theory history: First proposed by Boston University biologist Lynn Margulis in the late 1960s, the Endosymbiont Theory proposed that the main organelles of the eukaryotic cells were actually primitive prokaryotic cells that had been engulfed by a different, bigger prokaryotic cell.
Margulis' theory was slow to gain acceptance, initially facing ridicule inside mainstream biology. Margulis and other scientists continued work on the subject, however, and now her theory is the accepted norm within biological circles. During Margulis' research on the origin of eukaryotic cells, she studied data on prokaryotes, eukaryotes, and organelles, finally proposing that similarities between prokaryotes and organelles, combined with their appearance in the fossil record, was best explained by something called "endosymbiosis" (meaning "to cooperate inside. ") Whether the larger cell provided protection for the smaller cells, or the smaller cells provided energy to the larger cell, this arrangement seemed to be mutually beneficial to all of the prokaryotes. While this sounded like a far-fetched idea at first, the data to back it up is undeniable. The organelles that seemed to have been their own cells include the mitochondria and, in photosynthetic cells, the chloroplast. Both of these organelles have their own DNA and their own ribosomes that do not match the rest of the cell. This indicates that they could survive and reproduce on their own. In fact, the DNA in the mitochondria is the most like that of bacteria causes typhus. Before these prokaryotes were able to undergo endosymbiosis, they first most likely had to become colonial organisms. Colonial organisms are groups of prokaryotic, single-celled organisms that live in close proximity to other single-celled prokaryotes.
