Those amazing slime moulds

Posted 24 January 2008 by PvM

Philip Ball reports in Nature on new findings that show how the slime mo[u]ld can anticipate periodic events. The actual paper is published as Amoebae Anticipate Periodic Events in Phys. Rev. Lett. 100, 018101 (2008) by authors Tetsu Saigusa, Atsushi Tero, Toshiyuki Nakagaki and Yoshiki Kuramoto

Abstract: When plasmodia of the true slime mold Physarum were exposed to unfavorable conditions presented as three consecutive pulses at constant intervals, they reduced their locomotive speed in response to each episode. When the plasmodia were subsequently subjected to favorable conditions, they spontaneously reduced their locomotive speed at the time when the next unfavorable episode would have occurred. This implied the anticipation of impending environmental change. We explored the mechanisms underlying these types of behavior from a dynamical systems perspective.

According to Ball, the mould was exposed to a rhythmic stimulus and showed that it learned when the next stimulus would arrive. The memory would slowly fade but could be reinforced by a later stimulus.

The team found that when the mould experienced three episodes of dry air in regular succession an hour apart, it apparently came to expect more: it slowed down when a fourth pulse of dry air was due, even if none was actually applied. Sometimes this anticipatory slow-down would be repeated another hour later, and even a third. The same behaviour was seen when the pulses were experienced at other regular time intervals — say, every half hour or every 1.5 hours. If the dry episodes did not recur after the first three, the amoeba's sense of expectation gradually faded away. But then applying a single dry pulse about six hours later commonly led to another anticipatory slowing in step with the earlier rhythm.

Ball explains the significance of these findings

Learning and memory — abilities associated with a brain or, at the very least, neuronal activity — have been observed in protoplasmic slime, a unicellular organism with multiple nuclei.

In other words, science has shown how unicellular organisms like the slime mould have the ability to learn and remember. Memory and learning seem to not be limited to us humans and can be found, as expected from an evolutionary perspective across organisms. The amoeba Physarum polycephalum is quite a performer as it has been able to navigate mazes and solve simple puzzles Nakagaki, T., Yamada, H. & A. Tóth. "Intelligence: Maze-solving by an amoeboid organism" Nature 407, 470 (2000).

The plasmodium of the slime mould Physarum polycephalum is a large amoeba-like cell consisting of a dendritic network of tube-like structures (pseudopodia). It changes its shape as it crawls over a plain agar gel and, if food is placed at two different points, it will put out pseudopodia that connect the two food sources. Here we show that this simple organism has the ability to find the minimum-length solution between two points in a labyrinth.

Nakagaki, T., Kobayashi, R., Nishiura, Y. & Ueda, T. "Obtaining multiple separate food sources: behavioural intelligence in the Physarum plasmodium" Proc. R. Soc. B 271, 2305-2310 (2004).

To evaluate performance in a complex survival task, we studied the morphology of the Physarum plasmodium transportation network when presented with multiple separate food sources. The plasmodium comprises a network of tubular elements through which chemical nutrient, intracellular signals and the viscous body are transported and circulated. When three separate food sources were presented, located at the vertices of a triangle, the tubular network connected them via a short pathway, which was often analogous to the mathematically shortest route known as Steiner's minimum tree (SMT). The other common network shape had high fault tolerance against accidental disconnection of the tubes and was known as cycle (CYC). Pattern selection appeared to be a bistable system involving SMT and CYC. When more than three food sources were presented, the network pattern tended to be a patchwork of SMT and CYC. We therefore concluded that the plasmodium tube network is a well designed and intelligent system.

23 Comments

Henry J · 24 January 2008

But their still just amoebaeses!!!!11!!

PvM · 24 January 2008

Worse, they seem to be smarter than some of us humans :-)

Henry J: But their still just amoebaeses!!!!11!!

Eric · 24 January 2008

Did the research cover the mechanism for the recording of the memory? I'd be really curious to learn about that.

PvM · 24 January 2008

Yes

Like all living organisms, slime moulds have built-in biochemical oscillators, like the human body clock. In other kinds of slime mould, these oscillators can create periodic ripple patterns in response to environmental stress, helping the organism coordinate its movements. Nakagaki's group thinks that the versatile rhythmic sense of Physarum stems from many different biochemical oscillators in the colony operating at a continuous range of frequencies. The team's calculations show that such a group of oscillators can pick up and 'learn' any imposed rhythmic beat, although the knowledge decays quickly once stimulus ceases. The calculations also show that a memory of the beat can stay within the system, and be released again by a single, later pulse — just as the researchers observed.

Eric: Did the research cover the mechanism for the recording of the memory? I'd be really curious to learn about that.

PvM · 24 January 2008

I am still hoping to find the original paper but here is an earlier abstract of a talk given by one of the authors

Single-celled organisms might be cleverer than previously thought. Anticipating events are higher functions performed by the brains of higher animals; their evolutionary origins and the way they self-organize, however, remain open questions. Here we show that an amoeboid organism can anticipate the timing of periodic events. The plasmodium of the true slime mold Physarum polycephalum moves rapidly under favourable conditions, but stops moving when transferred to less-favourable conditions. Plasmodia exposed to unfavourable (low-temperature and low-humidity) conditions, presented in three consecutive pulses at constant intervals, reduced their locomotive speed in response to each episode. When subsequently subjected to favourable conditions, the plasmodia spontaneously reduced their locomotive speed at the time point when the next unfavourable episode would have occurred. This implied anticipation of impending environmental change. After this behaviour had been evoked several times, the locomotion of the plasmodia returned to normal. We explored the mechanisms underlying these behaviours from a dynamical systems perspective. Our results hint at the cellular origins of primitive intelligence and imply that simple dynamics might be sufficient to explain its emergence.

Once again, simplicity gives rise to complexity.

Phil · 24 January 2008

Heh. I saw the headline for this post and figured it was about DI somehow...

djlactin · 24 January 2008

Quote-mine alert!! Wonder how long before the DI posts this quote?

well designed and intelligent system

"Intelligent" and "design" in the same sentence?!

W. Kevin Vicklund · 24 January 2008

When three separate food sources were presented, located at the vertices of a triangle, the tubular network connected them via a short pathway, which was often analogous to the mathematically shortest route known as Steiner’s minimum tree (SMT).

So even slime molds are smarter than Salvador Cordova! Signed, The Master of MacGuyvers

russell · 24 January 2008

we get them in the yard. sometimes a foot across. yellow ones and pink ones.
dang big for a unicellular "critter".
never knew they could be trained.
wonder what neat tricks we could teach them?

Stanton · 24 January 2008

russell: we get them in the yard. sometimes a foot across. yellow ones and pink ones. dang big for a unicellular "critter". never knew they could be trained. wonder what neat tricks we could teach them?

"Eat Tokyo, then New York"?

David Stanton · 24 January 2008

Russell wrote:

"never knew they could be trained. wonder what neat tricks we could teach them?"

Well I just read a paper that reported altruism in cellular slime molds. I'll look up the reference if anyone is interested. Just goes to show that the evolution of altruism is not limited to social insect and primates.

Stanton · 24 January 2008

David Stanton: Russell wrote: "never knew they could be trained. wonder what neat tricks we could teach them?" Well I just read a paper that reported altruism in cellular slime molds. I'll look up the reference if anyone is interested. Just goes to show that the evolution of altruism is not limited to social insect and primates.

That sounds fascinating. How does altruism in cellular slime molds work?

pvm · 24 January 2008

link

Abstract: Cellular slime molds (CSMs) possess a remarkable life cycle that encompasses an extreme act of altruism. CSM cells live as individual amoebae until starved, then aggregate and ultimately transform themselves into a multicellular fruiting body. This fruiting body consists of stalk cells (altruists that eventually die) and spores (the beneficiaries of this sacrifice). Altruistic systems such as this are vulnerable to cheaters, which are individuals unrelated to the altruists that obtain the benefits provided by them without reciprocating. Here, we investigate two forces that can maintain CSM altruism despite cheating: kin selection and anticheater adaptations. First, we present new kinship‐based models based on CSM developmental biology to evaluate the efficacy of kin selection. These models show that stalk‐making genotypes can still be maintained when aggregations are initiated by multiple “founder” spores, provided that spores of stalkless fruiting bodies have low rates of dispersal and dispersal success is a concave function of stalk height. Second, we review proposals that several features of CSM development, such as the chemical suppression of the redifferentiation of prestalk cells into prespores, act as anticheater adaptations.

pvm · 24 January 2008

and

Evolutionary dynamics of altruism and cheating among social amoebas Å Brännström and U Dieckmann

David Stanton · 25 January 2008

Thanks PvM.

Pole Greaser · 26 January 2008

How can evolutionists explain this in terms of random motions of atoms? How does the amoeba solve the maze if everything it does is random and not informed by intelligent design? This seems to be a problem for Darwinism.

pvm · 27 January 2008

No it is a problem for those who misunderstand evolution to be random. Jeez...

Pole Greaser: How can evolutionists explain this in terms of random motions of atoms? How does the amoeba solve the maze if everything it does is random and not informed by intelligent design? This seems to be a problem for Darwinism.

David Stanton · 27 January 2008

Pole Greaser,

How can you understand anything given the random motion of atoms in your head?

Seriously, this is just another example of how modern evolutionary theory helps us to understand the interactions between differrent organisms, such as mating strains of slime molds. Read the paper and see what hypotheses were tested and what the results were. Then, if you think that an intelligent design hypothesis is a better explanation, by all means, describe the hypothesis for us and describe how it can be tested.

In case you missed the point, everything the slime mold does is not "random". The interactions are governed by evolutionary principles and the system continues to evolve. Throwing out the word "random" every time you don't understand something only convinces people that you don't know what that word means either.

Ash · 27 January 2008

"Pole Greaser" is trolling, if you can't tell by the name.

Pole Greaser · 27 January 2008

David Stanton: Pole Greaser, How can you understand anything given the random motion of atoms in your head? Seriously, this is just another example of how modern evolutionary theory helps us to understand the interactions between differrent organisms, such as mating strains of slime molds. Read the paper and see what hypotheses were tested and what the results were. Then, if you think that an intelligent design hypothesis is a better explanation, by all means, describe the hypothesis for us and describe how it can be tested. In case you missed the point, everything the slime mold does is not "random".

Whenever something is non-random, it is a product of intelligent design. Now matter how low the p-value gets, Darwinism insists the chance hypothesis must be correct!

The interactions are governed by evolutionary principles and the system continues to evolve. Throwing out the word "random" every time you don't understand something only convinces people that you don't know what that word means either.

rog · 27 January 2008

PG,

Wrong. The water molecules in a snow flake are not arranged randomly and not a product of intelligent design. This also holds for the salt and sugar crystals in you kitchen.

David Stanton · 27 January 2008

Pole Greaser wrote:

"Whenever something is non-random, it is a product of intelligent design."

Wow, what a break through! You should tell Behe and Dembski, now they can stop arguing over all that specified complexly complexified complex complexity stuff. As rog has already pointed out, lots of things that are "non-random" cannot reasonably be construed as being caused by "intelligence", unless of course everything is caused by "intelligence", in which case it explains exactly nothing.

And thanks for once again ignoring all my questions. Here is another one for you. Please define natural selection and show how it is either "random" or "intelligent" if those are the only alternatives you see.

Elizabeth Hensley · 8 October 2008

I second Eric's comment

Eric said

"Did the research cover the mechanism for the recording of the memory? I’d be really curious to learn about that."

Further research along this line could lead to an interesting and possibly practical bio-computer.

Also concerning evolution and Intelligent Design, the two are hardly mutually exclusive. Mickey Mouse is definitely going through gradual changes which fits the definition of evolution and assuming we fit the definition of intelligent, he is definitely intelligently designed. First he was in black and white, soundless, colorless, had no pupils and no ability to interact with his creators. Then his creators gave him a voice, then mutated him into a Technicolor rodent, then added pupils and now he is beginning to be able to teach the children of his creators simple math, the alphabet and colors. As AI and the laws concerning them continue to evolve, Mickey Mouse might successfully run for political office some day! Hey I'd vote for him right now rather than either presidential candidate! :0)

Evolution is such a wonderful thing. It has not stopped yet, has a good 10 to 15 billion years of Universe left to work and has produced a creature who longs for immortality and has the strength to go after it with the same tenacity we used to use to run prey to exhaustion, a method of hunting no other animal on the planet could use. That tenacity and faith will take us to the stars, and build Heaven just as we build the submarine Nautilus, the Moon ship Columbia and the International Space Station. Due to science we will go around curved relativitistic space/time upload everyone's organically produced operating system, including the Galilee Carpenter's and give Him His Kingdom. Because we can. Because we want to. No other reason is necessary.

Creationists look for God at the wrong end of the Universe. It is not only slime mold that goes through an altruistic stage and binds together to form one being. We do that too. But of course since time and space curve, bent by the gravitational mass of the Universe, the future is the past so God already exists.

Behold the evolution of God!

1 Corinthians 12:27. We are the Body of Christ and Individually Members of Him.

(Ephesians 4:15) "Rather speaking the truth in love we are to grow up in ALL WAYS into the Head, into Christ

(Ephesians 4:10) "He who descended is also He who ascended far above the Heavens that He might fill all things."

(Gospel of Thomas, verses 18 and 19) "The disciples said to Jesus, "Tell us, how will our end come?"

Jesus said, "Have you found the beginning, then, that you are looking for the end? You see, the end will be where the beginning is. Congratulations to the one who stands at the beginning: that one will know the end and will not taste death." Jesus said, "Congratulations to the one who came into being before coming into being. If you become my disciples and pay attention to my sayings, these stones will serve you."

We build Heaven. After all Christ is a Carpenter and we are His Body, and all Carpenters use their bodies to build things.

http://www.proofgodexists.org