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View Diary: A More Ancient World (Biodiversity Diary): Coevolution (57 comments)

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  •  That's an interesting idea (6+ / 0-)
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    RonV, tgypsy, palantir, bobsc, aoeu, whaddaya

    I haven't heard that proposed.  What is known is that our cells themselves are the results of mutualisms.  Specifically that the mitochondria (cellular structures that metabolize food in the presence of oxygen) are derived from bacteria that took up residence inside ancestral cells.  Similarly the chloroplasts of plants are derived from a group of bacteria (Cyanobacteria) that are capable of photosynthesis.

    Lynn Margulis, an eminent biologist, has claimed that this sort of mutualism was extremely widespread and responsible for most of the structures of eukaryotic cells (the cells of most nonbacterial forms of life).  This is possible but I don't think she or anyone else has been able to collect much in the way of convincing evidence.  In contrast both mitochondria and chloroplasts have remnants of their original structure and still have some of their own DNA.  They are clearly derived from other organisms.

    There are other examples of this type of relationship.  A number of organisms have taken in algae (algae means any organism capable of photosynthesis that falls outside of the plants in the strictest sense of the word) and basically taken over the algal chloroplasts for themselves.  The zooxanthellae organisms in coral have done this which means that photosynthesis in the coral is a mutualism involving four different organisms: the coral, the zooxanthellae, the algae that the zooxanthellae took in, and the cyanobacteria that originally formed the chloroplasts.

    "We are normal and we want our freedom" - Bonzos

    by matching mole on Sun Oct 10, 2010 at 07:28:04 PM PDT

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