Did Bacteria Developed Into More Complex Cells Much Earlier in Evolution Than Thought?

[n2doc]

ScienceDaily (Feb. 8, 2010) — Monash University biochemists have found a critical piece in the evolutionary puzzle that explains how life on Earth evolved millions of centuries ago.


The team, from the School of Biomedical Sciences, has described the process by which bacteria developed into more complex cells and found this crucial step happened much earlier in the evolutionary timeline than previously thought.

Team leader and ARC Federation Fellow Trevor Lithgow said 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.

more:
http://www.sciencedaily.com/releases/2010/02/100205091829.htm

[Laura902]

1. wait?

i thought the world was created by god 6000 years ago, you must be wrong!!!!!
just kidding, but in all seriousness very interesting! :D

[LynzM]

2. Neat!

Thanks for sharing; I'll definitely be re-posting this one!

[hunter]

3. This is a confusing article. Which, what bacteria?

You've got a three domain system, the Archaea, Eukarya and Bacteria.

The Archaea are the old guys, the "seeds" of life on Earth, wherever or however that came from. Somewhere in an early sea, a pond, from Martian meteorites, from deep space, who knows?

The Bacteria are the trimmed down hot-rod-clean-the-crap-out-of-the-closet optimized for Earth version of that, which sort of limited their potential for complex multicellularity and other future development, but made them the most common life form on Earth.

The Eukarya are the hoarders and builders among the Archaea: the we'll grab and glom onto whatever we find, our neighbors, our sisters, and what the heck we'll even incorporate completely separate lineages into ourselves as mitochondria, chloroplasts, and even the machinery that keeps our ramshackle DNA neat and turns our spermatozoa into swimmers.

So, I suppose in this article they are talking about how the Archaea incorporated their cousin Bacteria into themselves??? It's not clear.

[muriel_volestrangler]

4. It's about how transport across the membrane, that mitochondria need to function, developed

Here's the paper:

Among the questions about the evolution of eukaryotes is the debate over how they acquired the membrane-bound organelle, mitochondria. Mitochondria produce energy in nearly all eukaryotic cells (1) and regulate cell metabolism by controlling the flow of factors such as ions, amino acids, and carbohydrates between themselves and the cytoplasm. Mitochondria evolved from a bacterial endosymbiont (an -proteobacterium), and this process depended on the establishment of new pathways that facilitated the import of proteins into and across the double membrane (inner and outer) of the ancestral endosymbiont. Herein lies a debate: How did the process of protein import in mitochondria—which facilitated the evolution of this organelle, and thus, eukaryotic cell evolution—arise? Was the process driven by the ancestral host cell or by the prokaryotic endosymbiont, or by both?

http://www.sciencemag.org/cgi/content/summary/327/5966/649

Combining this with the comments from the press release:

"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."

and the title "Did Bacteria Developed Into More Complex Cells Much Earlier in Evolution Than Thought?", I think this means that since the 'cobbling together' from pre-existing parts was possible, a true eukaryote probably developed earlier than the previous estimate of 2 billion years ago.