An answer to another of life's big questions | ScienceBlog.com -
... the research explained how mitochondria -- the power house of human and other cells, which provide complex eukaryotic cells with energy and ability to produce, divide and move - were thought to have evolved about 2000 million years ago from primitive bacteria.
"We have now come to understand the processes that drove cell evolution. For some time now the crux of this problem has been to understand how eukaryotes first came to be. The critical step was to transform small bacteria, passengers that rode within the earliest ancestors of these cells, into mitochondria, thereby beginning the evolution of more complex life-forms," Professor Lithgow said.
The team found that the cellular machinery needed to create mitochondria was constructed from parts pre-existing in the bacterium. These parts did other jobs for the bacterium, and were cobbled together by evolution to do something new and more exciting.
"Our research has crystallised with work from other researchers around the world to show how this transformation happened very early on -- that the eukaryotes were spawned by integrating the bacterium as a part of themselves. This process jump-started the evolution of complex life much more rapidly than was previously thought."

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