Origin of Eukaryotic Cells by Intra-Cellular Natural Selection
Jensen, T.E.
Lehman College, Biology Department, 250 Bedford Park Boulevard,
West Bronx, New York 10468, USA
The eukaryotic cell undoubtedly came from a prokaryote. Prokaryotic cells are not necessarily just a membrane limited unit with ribosomes, DNA and perhaps a storage material. Prokaryotic cells have been shown to possess a wide array of inclusion bodies. In one group of prokaryotes, the Cyanobacteria, they have been shown to collectively possess some 35 different inclusion bodies of various morphologies. This is correct for present day Cyanobacteria and it is most likely the case for other prokaryotic groups going back in time before eukaryotic cells existed. These inclusions in prokaryotes probably came and went with the passage of time. However, if an inclusion would allow more efficient cellular reproduction then by Natural Selection this cell line and the inclusion would be retained. This production of an inclusion and then its loss if no benefit was derived by the cell has gone on for about 3.5 billion years. At some point in time a nucleus was formed in a prokaryotic cell. Most evolutionary biologists agree it was an endomembrane event. If a complex structure like the nucleus could arise by an endomembrane event then most likely other inclusion could arise in the same way. Thus other membrane limited and/or comprised structures such as mitochondria, chloroplasts, Golgi apparatus and etc. probably arouse in a similar manner by Intra-Cellular Natural Selection. We can see from this that there is no need to utilize an endosymbiotic scenario to explain the origin of the eukaryotic cell and the inclusions found in it. The eukaryotic cell with its inclusion came into existence by Intra-Cellular Natural Selection in the same manner that birds, fish and etc. came into existence by Natural Selection.
| LOCATION |
DATE |
TIME |
| Lecture Hall I |
Tuesday, April 7 |
03:00 pm |