It gives hints about the emergence of multicelular organisms. The next step is to detect and kill non clones (that can have genes that codify exploitative behaviours). These non clones will be renamed "infections" or "cancer". The following step is further specialization and tissues.
The evolution of this behaviour from non social bacterias can be retrodicted using evolutionary theory: first, the idividualist bacteria go alone to the light to the hguest point in order to be transported by the wind. In the process, they climb one over another. The bottom ones die, but since the upper ones are their clones, both win. the upper ones and get transported, the bottom ones die. 2014-04-25 9:26 GMT+02:00, Alberto G. Corona <[email protected]>: > Just to contain the enthusiasm within rational levels: > > There is no comunism neither comunitarism at all. It is a fight > between groups of clones that try to exploit one another (see below). > The clones are comunists (because are clones, like the social > insects). > > However the phenomenon is fascinating. > > > From http://www.nature.com/nature/journal/v408/n6815/abs/408965a0.html > > ...If aggregating cells come from multiple clones, there should be > selection for clones to exploit other clones by contributing less than > their proportional share to the sterile stalk. Here we use > microsatellite markers to show that different clones collected from a > field population readily mix to form chimaeras. Half of the chimaeric > mixtures show a clear cheater and victim. Thus, unlike the clonal and > highly cooperative development of most multicellular organisms, the > development of D. discoideum is partly competitive, with conflicts of > interests among cells. These conflicts complicate the use of D. > discoideum as a model for some aspects of development, but they make > it highly attractive as a model system for social evolution. > > 2014-04-25 9:10 GMT+02:00, Bruno Marchal <[email protected]>: >> >> On 25 Apr 2014, at 07:39, Samiya Illias wrote: >> >>> Does scientific research back the claims made in this article? >> >> >> Yes. Social amoeba are unicellular (capitalist) in good time, and >> become communist in hard time. May be we should learn from them. >> >> I say yes but there are some details which I have not the time to >> verify, of course. Notably the elimination of the cheater mutant. That >> is quite plausible though. The Dictyostelium discoideum is a quite >> fascinating organism, or should we say colony of organisms? >> The communication means here are still very rudimentary, though, and I >> don't think there are evidence for the "double word" communication >> mentioned in the thread. >> >> Bruno >> >> >> >> >>> Samiya >>> >>> Amoebic Morality <http://www.damninteresting.com/amoebic-morality/ > >>> >>> >>> Dictyostelium discoideum composite photo, Copyright © M.J. Grimson & >>> R.L. Blanton; Biological Sciences Electron Microscopy Laboratory, >>> Texas Tech University >>> Once food had been plentiful, but no longer. In the early days of >>> the colony, the amoebas had feasted on a rich supply of bacteria. >>> But as the generations passed and the population swelled, they had >>> hunted out their food supply. Now starvation threatens. Their home-- >>> a scrap of deer dung which once provided all their needs-- has >>> become a trap which they must escape if they are to survive. At >>> last, one amoeba sends out a cry for help. >>> >>> The starving amoeba begins to emit a chemical signal in the form of >>> cyclic adenosine monophosphate, or cAMP. Nearby individuals sprout >>> new pseudopods and crawl toward the source. They also begin to give >>> off cAMP themselves, amplifying the call until the signal spreads to >>> the far reaches of the colony. Amoebas cannot concurrently detect >>> and produce cAMP, so they alternate, and the cells trace out >>> intricate spiral patterns as they surge forward in waves. >>> >>> The amoebas pile on top of one another in growing numbers until so >>> many of them have joined the heap that this pile of microscopic >>> single-celled organisms becomes visible to the naked eye. At first >>> their behavior might seem odd; to gather together in the face of >>> starvation surely ought to end in cannibalism or death. Not so, for >>> they are capable of an extraordinary and rare transformation. The >>> amoebas set aside their lives as individuals and join ranks to form >>> a new multicellular entity. Not all the amoebas will survive this >>> cooperative venture, however. Some will sacrifice themselves to help >>> the rest find a new life elsewhere. >>> >>> These astonishing creatures are Dictyostelium discoideum, and they >>> are a member of the slime mold family. They are also known as social >>> amoebas. Aside from the novelty value of an organism that alternates >>> between unicellular and multicellular existence, D. discoideum is >>> highly useful in several areas of research. Among other things, this >>> organism offers a stellar opportunity to study cell communication, >>> cell differentiation, and the evolution of altruism. >>> >>> In response to the cAMP distress call, up to one hundred thousand of >>> the amoebas assemble. They first form a tower, which eventually >>> topples over into an oblong blob about two millimeters long. The >>> identical amoebas within this pseudoplasmodium-- or slug-- begin to >>> differentiate and take on specialized roles. >>> >>> The slug begins to seek out light, leaving a slimy trail behind. >>> Some of the amoebas take on the difficult role of sentinel, or >>> immune-like functions. They circulate through the slug, hunting for >>> pathogens. If they find any, they will engulf them in a process >>> similar to the feeding behavior they once displayed when in solitary >>> form. The pseudoplasmodium periodically sloughs off the sentinels-- >>> and any pathogens they have engulfed-- and abandons them in the >>> trail of slime. More cells will then be tapped to fill their place. >>> >>> >>> >>> Dictyostelium discoideum slug >>> Once the slug finds a suitably sunny location, the unlucky cells at >>> the "head" of the slug form a stalk for the others to climb. These >>> cells--which make up roughly a fifth of the total population--will >>> sacrifice themselves in order to provide a path up for their comrades. >>> >>> The remaining cells then climb the stalk and collect on its tip, >>> eventually resulting in a structure resembling a ping-pong ball >>> balanced on top of a floppy wire. This formation is known as a >>> "fruiting body." They then form spores, which are carried away by >>> wind or passing animals or insects. Once carried to a suitable >>> location, the amoebas emerge from spore form and begin the cycle >>> again. >>> >>> So long as all the amoebas which make up the slug are related, this >>> impressive display of self-sacrifice on the part of the stalk cells >>> makes sense. Though they will perish in the act of creating the >>> stalk, they will pass along their genetic legacy via their kin. In >>> fact, when the amoebas reproduce by division, they create an ever- >>> increasing pool of genetically identical clones. These clones suffer >>> no genetic cost at all from sacrificing their lives for each other. >>> >>> More familiar multicellular organisms pool resources in a similar >>> way. For example, in a human being, a liver cell fills a very >>> different role from a lung or skin cell, but all of them harbor the >>> same chromosomes. The result is that the liver doesn't need to >>> compete with the lungs concerning reproduction. So long as the germ >>> cells get lucky, all of the cells can be (metaphorically) content >>> knowing they will pass on their genetic legacy. >>> >>> However, when the cAMP call goes out, it isn't only related amoebas >>> that answer it. Those of differing strains will come together to >>> form a single slug. If one strain could figure out a way to duck out >>> of stalk and sentinel duty, it would be expected to reproduce faster >>> than its nobler compatriots. >>> >>> As is true with all organisms, some will evolve in such a way that >>> they can-- and will-- benefit from the colony's resources without >>> contributing anything back. In theory, such "leeches" could >>> potentially have a survival and reproductive advantage, thereby >>> undermining the cooperative Dictyostelid lifestyle. Such cheating >>> does take place, but nonetheless D. discoideum has been around for >>> millions of years with no signs of imminent extinction. Thus the >>> mechanisms for keeping cheating under control must be effective. >>> >>> For one thing, the amoebas prefer to unite with kin. The amoebas are >>> able to recognize each other through molecular markers. They mingle >>> with other strains only when populations are low. At such times, the >>> ability to form a larger slug outweighs the risk of cooperating with >>> strangers. >>> >>> >>> >>> A typical amoeba >>> In addition, evidence suggests that some social amoebas have evolved >>> to link reproductive genes with altruistic ones. In the case of D. >>> discoideum, researchers created a mutant strain of cells which are >>> "deaf" to the chemical signal to become a self-sacrificing stalk >>> cell. They then watched to see if these cells would gain a >>> reproductive advantage. Just the opposite took place. The "cheater" >>> mutant cells did not join in stalk formation, yet they rarely made >>> it up the stalk to become spores, and therefore they died out. The >>> traits of self-sacrifice and reproduction had become genetically >>> entangled, it seems, allowing only the altruistic amoebas to produce >>> offspring. >>> >>> Finally, opportunities for cheating simply aren't very common. In >>> the wild, these creatures spend much of their lives reproducing via >>> division, and surrounding themselves with identical copies. Outside >>> of laboratory experiments, cases where social amoebas run across >>> strangers to exploit are rare. Cheater genes peter out once the >>> cheaters run out of nobler amoebas to sponge off of. When exploiting >>> one's clone mates, greed doesn't pay. >>> >>> In addition to studies of altruism, study of D. discoideum is >>> shedding light on how cells communicate. D. discoideum uses many of >>> the same signaling processes found in all multicellular creatures. >>> But unlike fish or frogs, D. discoideum can be frozen, thawed, grown >>> by the millions in a matter of days, and stored away for years if >>> need be. A website called DictyBase offers an impressive list of >>> breakthroughs which can be credited to the social amoeba. >>> >>> The consistency with which these amoebas act in the common good >>> might inspire admiration in many. Yet a more cynical observer might >>> point out that the amoebas are moved not by love of family and >>> friends, nor by moral scruples, but by the cold mechanics of natural >>> selection. Amoebas behave altruistically only because natural >>> selection has led to a stable state in which self-sacrifice is the >>> best way for them to pass on their genes. But the end result is the >>> same, regardless of the natural forces that have shaped it. Altruism >>> triumphs, and through their mutual selflessness the amoebas arrive >>> at a new patch of bacteria-laden dung to call home. >>> >>> Written by Carol Otte, posted on 09 October 2007. Carol is a >>> contributing editor for DamnInteresting.com. >>> >>> >>> >>> On Thu, Apr 24, 2014 at 6:54 PM, Bruno Marchal <[email protected]> >>> wrote: >>> >>> On 24 Apr 2014, at 12:26, Richard Ruquist wrote: >>> >>>> Microbes provide insights into evolution of human language >>>> April 23rd, 2014 in Biology / Cell & Microbiology >>>> >>>> Gram-stained Pseudomonas aeruginosa bacteria (pink-red rods). >>>> Credit: GFDL, CC-by-sa >>>> >>>> Big brains do not explain why only humans use sophisticated >>>> language, according to researchers who have discovered that even a >>>> species of pond life communicates by similar methods. >>>> >>>> Dr Thom Scott-Phillips of Durham University led research into >>>> Pseudomonas aeruginosa, a type of bacteria common in water and >>>> soil, which showed that they communicated in a way that was >>>> previously thought to be unique to humans and perhaps some other >>>> primates. >>>> >>>> The bacteria used combinatorial communication, in which two signals >>>> are used together to achieve an effect that is different to the sum >>>> of the effects of the component parts. This is common in human >>>> language. For example, when we hear 'boathouse', we do not think of >>>> boats and houses independently, but of something different - a >>>> boathouse. >>>> >>>> This type of communication had never been observed in species other >>>> than humans and some other primates, until colonies of Pseudomonas >>>> aeruginosa were shown to be using the same technique - not, of >>>> course, with spoken words but with chemical messengers sent to each >>>> other that signalled when to produce certain proteins necessary for >>>> the bacteria's survival. >>>> >>>> By blocking one signal, then the other, the researchers showed if >>>> both signals were sent separately, the effect on protein production >>>> was different from both signals being sent together. >>>> >>>> Dr Scott-Phillips, a research fellow in evolutionary anthropology >>>> at Durham University, conducted the research in collaboration with >>>> a team of experts in bacteriology from the universities of >>>> Nottingham and Edinburgh. >>>> >>>> He commented: "We conducted an experiment on bacterial >>>> communication, and found that they communicate in a way that was >>>> previously thought to be unique to humans and perhaps some other >>>> primates. >>>> >>>> "This has serious implications for our understanding of the origins >>>> of human communication and language. In particular, it shows that >>>> we can assume that combining signals together is unique to the >>>> primate lineage." >>>> >>>> More information: 'Combinatorial communication in bacteria: >>>> Implications for the origins of linguistic generativity', Scott- >>>> Phillips et al, published in PLOS One, 23 April 2014. >>>> www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0095929 >>>> >>>> Provided by Durham University >>>> >>>> "Microbes provide insights into evolution of human language." April >>>> 23rd, 2014. >>>> http://phys.org/news/2014-04-microbes-insights-evolution-human-language.html >>> >>> >>> The contrary would have astonished me a lot, but it is nice this is >>> confirmed and studied (I was sure it was). Comparison with language >>> might be slightly stretched as there is no symbolic role in the >>> messages, but may be it can make sense (I am not sure, I will read >>> the paper ... but that does not seem really in his topics). I have >>> few doubts that our own cells communicate in very sophisticate >>> chemical ways, and there are evidences that plants does communicate >>> through their roots, may be even through bacteria. (But no proof of >>> such explicit double "words" nuancing, although again, its non >>> existence would be astonishing). I would have bet this was already >>> discovered on Escherichia Coli, but not in that apparently explicit >>> way. >>> Hmm... I'm not sure that they verified enough that the two compounds >>> don't react to get a third molecule, which would trivialize the >>> discovery. >>> So interesting, but has to be continued and confirmed, ... >>> >>> Bruno >>> >>> >>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Everything List" group. >>>> To unsubscribe from this group and stop receiving emails from it, >>>> send an email to [email protected]. >>>> To post to this group, send email to everything- >>>> [email protected]. >>>> Visit this group at http://groups.google.com/group/everything-list. >>>> For more options, visit https://groups.google.com/d/optout. >>> >>> http://iridia.ulb.ac.be/~marchal/ >>> >>> >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Everything List" group. >>> To unsubscribe from this group and stop receiving emails from it, >>> send an email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/everything-list. >>> For more options, visit https://groups.google.com/d/optout. >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Everything List" group. >>> To unsubscribe from this group and stop receiving emails from it, >>> send an email to [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/everything-list. >>> For more options, visit https://groups.google.com/d/optout. >> >> http://iridia.ulb.ac.be/~marchal/ >> >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Everything List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/everything-list. >> For more options, visit https://groups.google.com/d/optout. >> > > > -- > Alberto. > -- Alberto. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
