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== Problems ==
== Problems ==
[[Image:Haeckel.jpg|right|250px|thumb|[[Ernst Haeckel]]'s [[homology]] arguments were later shown to be erroneous evolutionary speculation and a fraud. Please see: [[Theory of Evolution and Cases of Fraud, Hoaxes and Speculation]]]]
[[Image:Haeckel.jpg|right|250px|thumb|[[Ernst Haeckel]]'s [[homology]] arguments were later shown to be erroneous evolutionary speculation and a fraud. Please see: [[Theory of Evolution and Cases of Fraud, Hoaxes and Speculation]]]]
* Neither mitochondria nor plastids can survive in oxygen or outside the cell, having lost many essential genes required for survival. The standard counterargument points to the large timespan that the mitochondria/plastids have co-existed with their hosts. In this view, genes and systems that were no longer necessary were simply deleted, or in many cases, transferred into the host genome instead. (In fact these transfers constitute an important way for the host cell to regulate plastid or mitochondrial activity.) For example, most plastids are not able to produce respiratory proteins necessary for respiration. Like any living cell, plastids would die if energy is not provided to them by respiration.
* Neither mitochondria nor plastids can survive in oxygen or outside the cell, having lost many essential genes required for survival.
* A large cell, especially one equipped for phagocytosis, has vast energetic requirements, which cannot be achieved without the internalisation of energy production (due to the decrease in the surface area to volume ratio as size increases). This implies that, for the cell to gain mitochondria, it could not have been a eukaryote, and must have been a bacterium. This in turn implies that the emergence of the eukaryotes and the formation of mitochondria were achieved simultaneously. This may be explained by possibly a very close symbiotic relationship between two types of bacteria which eventually led to gene exchange and engulfing of the mitochondria precursors through partial fusion or engulfing by the host bacteria.
* A large cell, especially one equipped for phagocytosis, has vast energetic requirements, which cannot be achieved without the internalisation of energy production (due to the decrease in the surface area to volume ratio as size increases). This implies that, for the cell to gain mitochondria, it could not have been a eukaryote, and must have been a bacterium. This in turn implies that the emergence of the eukaryotes and the formation of mitochondria were achieved simultaneously.
* Genetic analysis of small eukaryotes that lack mitochondria shows that they all still retain genes for mitochondrial proteins. This implies that all these eukaryotes once had mitochondria. This objection can be answered if, as suggested above, the origin of the eukaryotes coincided with the formation of mitochondria. Alternatively, we may postulate extinction of all other descendants of a mitochondrion-free ancestral eukaryote, perhaps due to competition from the symbiotic clade, or oxygen poisoning as levels continued to rise.
* Genetic analysis of small eukaryotes that lack mitochondria shows that they all still retain genes for mitochondrial proteins.
== History ==
== History ==