© 2007 All Rights Reserved. Do not distribute or repurpose this work without written permission from the copyright holder(s).
Printed from https://www.damninteresting.com/amoebic-morality/
Damn Interesting is delighted to introduce Carol Otte, one of our brand-spanking-new contributors! Exclamation point!
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.
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.
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.
© 2007 All Rights Reserved. Do not distribute or repurpose this work without written permission from the copyright holder(s).
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^it’s funny because I’m sure someone is going to get offended by that :]
I’m offended, as I registered just to try to get the first comment. I guess that’s what I get for reading first ;)
At any rate, damn interesting article, Carol!
Great job Carol! Who knew these microscopic organisims could be so interseting.
Welcome to DI! Carol Otte! Thanks for the cool article. Reminds me of many people I know. Some are stems and heads and some are leaches, And some are just plain slime balls.
I hope Alan warned ya that this will probably bring out the readers who enjoy debateing the E word, lol. Just let any derogatory comments ooz on by ya, and don’t take any of those to heart. Hope to see more of your work in the near future! Thanks again, Tink
P.S. Second! %-)
RE:P.S. Second…LOL, never-mind!
Yup, despite being “blind,” evolution is one crafty and creative mechanism. :-)
Very interesting! I’ve heard of slime moulds before but nothing like these working together!
Seriously, though… I’m a Creationist, and regardless of how this Amoeba came about, it’s still quite an interesting little critter. I love lifeforms that defy categorization (multicellular? single cell?).
9th! I’m in the top ten! At last. This was a really interesting read. I have often contemplated what the evolutionary drive behind single cells banding together could have been.
Damn interesting indeed…and very fascinating! Great article Carol…You did an excellent job :-)
Congratulations, you made amoebas damn interesting. That takes talent!
Damn Interesting and Damn Entertaining. Thanks, Carol!!!
Oorah! Excellent teamwork you amoebas! I’m so damn proud of all you! Carol, all ribbing aside, I thoroughly enjoyed your article. I had no idea about this! Looking forward to reading more stories from you.
FINALLY!!! A science related article! These are few and far between with random WWII articles and history lessons. Don’t get me wrong.. they are all interesting but this was a breath of fresh air..
Cheating Cells interest me a lot. But whats that saying:
“Cheaters never pro-.. I mean they never potentially have a survival and reproductive advantage, thereby undermining the cooperative Dictyostelid lifestyle.”
yea thats the one.
Enter your reply text here.Ha! I knew it, those biology experiments in the back of my refrigerator are moving.
Good article, interesting read..
time i am posting a comment… :-D
that is how human society should be strucutured too.
there’s too little food, damn it
sorry brother you gotta die so we can make a ladder from your corpse and get outta this place…
They should give these little guys pie instead of dung and see what they do.
Good stuff! I think i saw something on discovery channel about these guys truly amazing!
It certainly lends credence to the fact that we don’t get our morals from a book or a sky fairy. It seems that even from day 1 we’ve been evolved to work together & not “cheat”. (very simplified version of the theory of course)
gosh darn interesting!
I think I was an ameoba in my past life.
WOW! These crazy amoeba are enjoying their 15 minutes of fame. I recently heard about people who have been killed by them….check out
I regularly visit this site, and often think “that’s more than damn interesting”, but I just had to join up to comment on this!!! Absolutely astounding. I love stuff like this, from tiny amoebas to Super novae, Nature is incredible. Fantastic.
Please give me more……………………………………………..
Haha! Imagine that in something like Black Hawk Down.
I love these science articles. I’m one of those people that loves knowing tonnes of useless but DI facts – and this one’s a doozie!
DI and well written Carol.
That’s what they are eating in the back of my refrigerator(pie, not dung.). You should see the size of those suckers!
This is amazing! I’ve never heard of a creature like this … it’s fascinating on so many levels.
You managed to write very poetically about it, by the way.
As someone else said, it’s nice to see a science article.
These guys could be seen as a missing link between single-celled and multicellular organisms. If they had developed along a different path, they may have reached a point where they were better off without returning to single-celled form.. and they may yet reach such a point.
Thank you so much for a science article. I’ve read Darwin and marveled at how when plants and animals are isolated like on an island they evolve and change to adapt to their environment These amoebas seem like they would not isolate in one place, but keep moving. It’s interesting that they seem to have not changed much over ka-billions of years. Could this be because they don’t isolate themselves to an environment or particular habitat?
Another thought about altruistic behavior in humans. What about when people donate blood, donate organs, stem cells, donate their body to science? It’s kind of like donating cells toward a greater cause? I don’t know, what do other people think?
We’re a little more complex than amoebas, but in the next few hundred years I bet there will be a lot of advancements that will make human components more interchangeable like car parts or something. I can imagine different strains of humans developing based on their decisions regarding what parts to clone and incorporate. Just like fashion where every woman wants and has to have the latest Coach fall handbag, maybe everyone will have to have the latest genetics available to grow hair like Jennifer Aniston? Or just like we all endeavor to upgrade to the razor cell phone with the camera function, and go from VHS to DVDs, humans could soon all be clamoring for the latest DNA upgrade to their immune system. Homo Sapiens 2.0?
“For one thing, the amoebas prefer to unite with kin.”
If even the amoebas tend to form clans, I hold little hope for humankind’s abandoning the old tribal ways. That, in essence, is the Middle East, in that the strongest associations are formed along bloodlines (as is the Mafia). Such groups are rarely defeated, unless one is willing to eradicate them entirely.
“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.” This brings up the distasteful idea that altruism and compassion work against the betterment of humankind. Darwin and the Nazis would have agreed, I think.
That was fascinating! I didn’t know amoebas could be so complex. Brilliant article, and nice to see some more science on here – and nicely explained too, even a science dimwit like me could understand it.
Well done, and congratulations on your first article! I’d been thinking of doing something on slime molds myself, but I’m glad you beat me to it.
I’m just creeped out by the whole idea of something that looks and reproduces like a fungus, but MOVES! Ick! And they look so gross! There’s one that looks like it’s bleeding, and another called the “dog vomit” slime mold, for obvious reasons…
(goes off singing:
“Beware of the Blob
Across the floor
And all around the wall
A splotch, a blotch
Be careful of the Blob…..”)
This article was incredibly DI! Thank you Carol and welcome!
I’m not surprised that human scientists saw a functioning system that runs on self-sacrifice and decided they should try and make it fail. Capitalists, right? *chuckle*
This article makes me think that we are even less special as a species. Banding together is obviously something that can be done mechanically at the single celled level.
On top of that all of our technological achievements arent that great when you consider it is simply one human building on top of what the previous human had done before them. If I remember correctly, coral reefs do something similar in that they build on top of the structure already present. They even go to war with each other (I’ve seen the time lapse of two reefs fighting, its awesome). Coral reefs could parallel us even more if they found ways to conquer their environmental conditions, but I have yet to see a reef knit a sweater to live in colder water.
Always neat to see a good science article to humble us as a species. DI
DI indeed! I’m a Molecular, Cellular, and Developmental Biology student at the University of Colorado at Boulder, and we’ve been working with these things in lab a ton this semester! It really is quite amazing to see them form the slug! The best part is that for the second half of the semester we get access to them to perform our own experiments… Hmmm perhaps I can teach them to do tricks?
Hilarious idea. Your post made me laugh. I never thought about it like that, and I like your point of view. It’s a DI perspective you’ve got going there. :)
Some time ago, in the 1980’s, David Suzuki hosted an episode of The Nature of Things that took a look at slime molds. Fascinating. They sped up film of the molds as they “scurried” across glass, and would even bifurcate given proper stimulus (like a knife edge in front of the moving mold). I’ve looked on the internet for more, but could only find this comment:
Regarding the second remark (above) about the parasitic amoeba. It was one of the most amazing things I’ve ever seen. The first amoeba starts to go into “fruiting body” mode, but part way there, from within the structure emerge the parasitic amoeba’s “fruiting body” elements.
I’m glad Damn Interesting brought this subject to the attention of readers.
If we could make these slime molds in fun colors like fuschia, neon green, tangerine, aquamarine, etc. they could make fun, trendy pets. :)
Or even teachers! (See Jeffrey Darlington’s webcomic, General Protection Fault, particularly the parts dealing with Fred the Slime Mold.)
Damn interesting indeed!
While I have no constructive comment to add about the article itself, I will add the following one in hope that Carol is reading this: Please, write something about yourself. That blank space in your profile is just so very scary now.
I’m sorry but “creationism” is an utter joke. There is no understanding of science.
Anyone who says “I’m a creationist” is automatically marked as ignorant in my book.
Anytime someone tries to separate science, and belief in a higher being, is automatically dumb-ified.
. . . FIRST!
I like this comment better than the #40 First, but then that’s just me. Does anyone think there are slime molds out there comprised of type A Amoebas just dying to be first to get to the dung pile before the other slime mold? And if so would they be the Capitalist slime molds?
Trully fascinating article, thank you Carol. I would have to agree with those who’d say that the amoebas self-sacrifice for the greater good not because of love and devotion, but because of natural selection. Correct me if I am wrong, but a unicelluar organisms would not experience love and devotion as we humans or even animals would feel because of their lack of complexity. The article said that the amoebas gather into this slug form because they are starving. Their self-sacrifice is out of instinct for survival for their specie. I wonder if there are other species or families of amoebas who do not do Altruism because they are not in an environment where they are starving. It would interesting to do an expemerient to see if other types of amoebas begin to do Altruism if they are put in similar situations as the D. discoideum.
^ oops, that’s “experiment” not “expemerient.”
That’s a really interesting comment and a little random. I wonder if you mean that science and belief in a higher being are the same thing, integrated or one outweighs the other.
I think it’s becoming a fashion at this site to compare First posters and wannabe First posters to whichever animals that happened to be talked about in the article (and not in a good way… unless you mean slime molds and vermins and amoebas in a good way, but I doubt that’strue). At any rate, it’s a bit unkind. Trully though, if you think about it, it’s not that big of a deal. It’s human nature. But if it bothers anyone so much, be a little mature and kindly shake your head in the comfort of your sorrounding instead of calling one another names.
Warning: Soapbox rant incoming… ;-)
I’m guessing this is directed towards QP’s comment (#8)? I’d tend to agree, but more in the non-insulting “unaware of the facts” meaning of the word. We all start out ignorant, so that isn’t necessarily a “character flaw,” as some people interpret the word. It’s only a problem if we insist on remaining ignorant. I find that many creationists either aren’t aware of the science behind evolution, or they’ve been mislead about the facts, often both, and they simply aren’t interested in hearing about the opposing science because they’ve already made up their minds. As long as they’re willing to keep an open mind and listen to the other side, I don’t care if someone wants to call themselves a creationist. It’s the close-minded “you’re wrong because God says I’m right” ones that bug me.
But if “higher beings” (a.k.a. “gods”) are defined as “supernatural” non-material beings, and science is defined as the study of the natural/material world, I don’t see how they can help but be separated. By definition, gods are beyond the ability of science to study. Some of the claims of religions can be studied by science, such as the claim that prayer can help the sick better than a placebo, but science cannot definitively answer the question of whether gods exist or not.
Also, I don’t think a “belief in a higher power” is a requirement before one can have ethics in science, if that’s was what you were implying (i.e. the old “Science without religion is lame, religion without science is blind” line.) Atheists can be, and often are, quite ethical.
It had to happen sometime …
I personally think that evolution and religion don’t go against each other at all. Just because God created everything doesn’t mean that they didn’t evolve after He created them.
That really was DI! I wonder if altruism (or at least being nice) is coded in our our genes as well. Granted there is an almost instinctual wariness of strangers, but if we fought everyone we met outside of our own “tribe”, there wouldn’t be much cooperation or trade between larger groups.
On the evolution vs. creationism thing… Who’s to say the universe itself isn’t an artifact? If I remember my high school physics right, if the the strong force that keeps protons and neutrons together in the nucleus of an atom were 5% weaker, matter as we know it wouldn’t exist. (corrections to my possibly erroneous memory are welcome)
Or we could just go on about the fleas’ having smaller fleas to bite ’em….
(The mind boggles, then shakes its head and tries to figure out more important stuff, like how to get some pie… ; )
The entire purpose of science is to prove itself wrong, whereas the adherents of a religion are supposed to accept, usually without question (“Blessed are those who do not see and yet believe…”). An indication of intelligence is a seeking of verifiable answers. Therefore, intelligent design is, by definition, not intelligent.
Dismissing something so easily is a rather un-scientific method to come to this conclusion. Have you no hypothesis? No experiments to prove this conclusion? I simply can not believe that creationists are ignorant unless you show me some kind of chart. Science demands hard evidence, right? Your post is evidence that you have no understanding of science, let alone it’s methods. Your conclusions are fallible.
Not here either.
You have no evidence to base your (Nicki’s) conclusion on: he did not state how he came to his conclusion.
My guess is, that he, like myself, have examined the evidence and come to the conclusion that there is as much evidence for Natural Selection as there is for gravity. Then, using deductive reasoning: (1) Any person impartially examining the facts must come to the conclusion that Natural Selection is a likely explanation (2) This person denies Natural Selection has any validity. Conclusion: the person in question has not impartially examined the facts (i.e. is ignorant, whether willfully or not). Of course, the person could be hypocritical instead of ignorant, but that is worse.
What really bothers me about these debates, is that often both sides assume that God and Natural Selection are mutually exclusive. I am with the majority of Americans: I believe in both.
Right you are, but that’s because my comment was satirical. Also, I didn’t say in my comment that I was on any particular side, or that either side is invalid. The truth is, I believe in creation AND evolution. It is the debate that irritates me as well. I’m bothered by people who take their iron stance and insult the intelligence of anybody who believes anything else, and was just pointing it out.
I had no idea Amoebas could perform such feat. Amazing!
Very interesting article. But…
It is not too surprising to see how cooperative behavior can give an advantage. Mother nature guides behavior in non-reasoning (and human) entities by making a behavior ‘feel good’.
To impute a philosophical decision to a primitive life form doing what comes naturally is at best a mistake.
Altruism, which is a controversial concept, poorly defined and carrying questionable moral and political connotations in most readers’ minds, is used to describe cooperative behavior that results in earlier cell death. But it is implied, in a dishonest package deal, that the cells DECIDE to sacrifice themselves for the good of the colony. This is anthropomorphism of the worst kind. My take on the behavior is that it feels so good that the cells race to be the first to be able to fulfill that role. Not that the cells are a bunch of little socialists competing to be the first to sacrifice themselves for the good of the herd.
It is not surprising that much of modern science is viewed through a prism imposed by the epistemology and ethics that support a socialistic university atmosphere. But it is a little disappointing to have to wade through the attempt to smuggle a moral lesson into a description of cell behavior. For some reason, when people preach altruism, it always somehow winds around to where it is ME that will be sacrificed. And somehow, it is OK for ‘disinterested’ scholars to decide that it will be me and not them.
When we can find evidence that such primitive organisms are able to think on a conceptual level, then perhaps we can explore whether their behavior is altruistic. Until then, it might be more productive to seek a simpler explanation.
Not exactly. Creationism makes no testable claims or predictions and thus is not falsifiable, which means that it is not a scientific concept. There are plenty of ways that various parts of evolution could falsified, the classic being “rabbits in the Precambrian” (J.B.S. Haldane), but can you name even one thing that could falsify creationists’ claim that God created the Universe and life on Earth? When you throw “God” into the mix you can “explain” any fact (or rather, not explain, since it’s actually just shifting any explanations off onto some thing that can’t be explained, examined, or tested.) Furthermore, if any and all evidence can fit a claim, then the claim can make no useful predictions either, which means it’s worthless as anything other than a philosophical concept. Evolution makes predictions that have been and are useful in medicine, psychology, and many other areas, creationism doesn’t.
Furthermore, proper reasoning does not accept things as true until proven false, it treats things as only being likely to be true when they best fit all of the facts, preferably after passing all attempts at proper falsification. It’s a bad idea to believe any claim until you can prove it wrong. If you did that then you’d be left believing an infinite number of contradictory things because you can’t disprove them. If, for example, I said that most buildings are built by Flying Purple Hippopotamuses when nobody is looking, you shouldn’t believe me until I have been proved wrong, and I think “ignorant” would be one of the more polite things you could reasonably call me.
Thus, contrary to what you claimed about his understanding of science, it is well in keeping with the scientific method to dismiss unprovable claims and people when they are insisting that those claims true.
You might want to rephrase that. ;-)
Thanks for playing along. You’ve caught on to what I am doing.
It’s vaguely put, I suppose, but not wrong. By “things” I meant “any and all things that you can think of”, which I hoped was clear in context. Meaning that you shouldn’t by default accept every idea as being true up until the time when you have been satisfied that it is false. Since some ideas cannot be falsified, it is better to start from an assumption of falsehood, and work your way up (or down) the probability scale as evidence is examined/produced as the claim is tested. Generally speaking, if a claim is unfalsifiable then it is useless, because it does not affect the world, if it did then it could be tested.
how on earth does something evolve tell me.
Huh?!?! Did you actually read the quote?! I presumed you meant we shouldn’t believe anything until it is falsifiable (i.e. has testable predictions), now I am not so sure. The famous example for falsifying evolution is finding a rabbit in the pre-Cambrian – it could happen, which would prove evolution false, but it hasn’t, so we take it as evidence that evolution (natural selection really) is true.
Nothing ever evolves alone, it is really a community (what scientists call a ‘genetic pool’) that evolves. Evolution really occurs between generations: offspring are different from, but similar to parents. The more fit those offspring are, the more likely they are to find a mate and have their own offspring. Over generations, less fit creatures fail to have offspring and disappear from the community, while more fit creatures thrive.
The definition of ‘fit’ varies from community to community: for a moth, it might be having markings that make it harder to see, so it doesn’t get eaten by birds. For a giraffe it might be having a longer neck, so it can reach those hard to get leaves. The definition of ‘fit’ can change when the environment changes – when a new predator appears, when the climate changes, etc.
Sometimes a community can split – either because it is physically separated into two groups, or because there are two mutually exclusive directions evolving, e.g. smaller – better able to hide from predators, vs. longer legs – better able to run away from predators.
Before I write anything else, I need to stress that I am not religious at all; actually, I am an atheist. I write this because I don’t want anyone to think that a religious belief motivates my words that will appear below.
Because I believe firmly that the first goal of science is to prove itself wrong (the null hypothesis of a theory), I am skeptical – not cynical – of all things that are currently accepted as true and proven. This attitude, of course, is at the core of the scientific process, and true scientists accept nothing as true, proven, and factual for the rest of eternity. As an example, the concept that nothing is faster than light was true; this is not true now.
I also want to stress that I understand the difference between an opinion and a theory. One can have an opinion about anything, and it doesn’t matter how absurd the opinion might be. A theory, though, is based upon rigorous scientific principles and can be tested repeatedly.
In regard to evolution, I have doubts about its reliability as a sound theory.
Much evidence exists that many creatures still exist as they did untold aeons ago. Consider, for example, crocodiles, alligators, and cockroaches, to name just a few.
Consider also the idea that, during the several ages of the various dinosaurs, they existed either unchanged or virtually unchanged until a cataclysm eliminated them. It seems that, given the millions upon millions of years they were supposed to have been on Earth, more changes would have occurred.
I must hold my opinion about minor changes in an organism resulting in a better fit with the environment and thus allowing that organism to survive better. As far as I can tell, the changes in any organism that we have observed in modern time have always been defects, not
improvements. Therefore, I doubt that the odds of a changed organism finding a mate with a similar change and producing offspring would be all that high. However, I hold my opinion because I cannot know what happened millions of years ago. Perhaps those changes did indeed result in an improved species.
The real question for me is this: Does change occur that results in an improved species or a new species? My answer is a resounding shoulder shrug. I have no idea. The best that I can do is to offer another idea that might result in a theory that can be tested.
For the purposes of logical argument, let’s assume that change within a species can occur. Perhaps these changes occur *only* as a reaction to a change in the environment. Moreover, perhaps these changes are fairly quick and do not require a great deal of time. Otherwise, the creature would not have enough time to adapt to the new environment and would die out.
Assuming that I understand evolution correctly, here’s the difference between my idea and evolution: *No mutation in the genetic code occurs.* In my idea, a species might have certain genetic traits that lie dormant unless an environmental event triggers them. Those species that already have those dormant traits will survive; those that don’t, won’t. If a species has those dormant traits but no environmental triggers have awakened them, the species remains in the state that has thus far functioned well in that environment. As I mentioned before, the alligator has allegedly remained unchanged for quite a while. Perhaps it has dormant genes, perhaps not. Whatever the case, the alligator seems to be able to function well in its environment, both now and then.
Of course, my idea does not deal with how the universe came into existence and all of its attendant creatures. That, I shall leave for the scientists to investigate. Who knows? Perhaps they will prove that the creationists are right, but they will do so by investigation and skepticism, not acceptance and blind faith.
This does not make evolution wrong: it simply means that there is no “evolutionary pressure” – that the crocodile or whatever is already optimally adapted to the environment.
Evolution has been very thoroughly tested, both in the fossil record, in current observations (e.g. antibiotic resistant bacteria) and even induced in experiments (mostly fruit fly experiments – they have a short lifespan). It’s about as well proven as gravity – do you doubt gravity?
The species boundary is defined as being (un)able to have viable, fertile offspring together. If the original species no longer exists, it is currently impossible to test if it is truly a new species, or just an improved species. There is also some wiggle room there: sometimes two sub-species cannot produce offspring together, while either can produce offspring with a third “middle-of-the-road” sub-species.
One of the more interesting experiments with fruit flies, involved separating them from each other and not letting them mate until the middle their normal mating life. After a few dozen generations, the fruit flies were much longer-lived and generally healthier, sturdier – “fitter” for that new environment. When the separation was removed, the fruit flies slowly reverted back to having shorter life-spans and being less sturdy – presumably because there is no advantage to fruit flies in having a longer life after having had their offspring.
Your hypothesis is more complex, requiring not only the changed gene, but that it be triggered by the correct environmental stimulus (e.g. what would prevent a thick fur coat being triggered by high temperatures instead of low temperatures?). I invoke Occam’s Razor: it makes things unnecessarily complex.
If creationism is proved right, then it won’t be God that is the creator: God, as understood by most major religions, exists outside the Universe as we know it – only something *inside* the Universe can be scientifically verified. This then begs the question, “who created the creator?”.
Thanks for posting your views. This has become an interesting exchange, and I greatly respect your ability and willingnes to present factual, unemotional, logical statements.
A few quick points:
1. Examining a fossil record does not necessarily represent proof. Because of the nature of science, previous conclusions must be revised when additional information is uncovered. Additionally, because of the nature of the physical remains of creatures, the fossil record is incomplete.
2. From my understanding of logic, using gravity to urge acceptance of evolution is faulty because they are not of the same category or of categories closely related enough to permit an analogy. Additionally, gravity is immediately verifiable; evolution is not.
3. I am fairly conversant with the work done with fruit flies. However, changes that occur within one species does not necessarily constitute true evolution, especially considering that you mentioned something of which I was unaware: “When the separation was removed, the fruit flies slowly reverted back to having shorter life-spans and being less sturdy – presumably because there is no advantage to fruit flies in having a longer life after having had their offspring.” Everything else that I had ever read about evolution indicated that the changes are permanent.
4. Perhaps evolution does occur with fruit flies. However, going from a microcosm to a macrocosm is a logical fallacy; assuming that a process that occurs within fruit flies is a priori proof for most or all species is neither logical nor scientific.
5. I am not sure that your invocation of Occam is applicable at this point. Perhaps my idea is actually simpler because the genes are already present but dormant. No change in the gene occurs, and no dormant gene becomes active unless a stimulus is present. Please remember that one of my main points is that the gene itself does not change.
6. In regard to your final point, I will reiterate that I am an atheist; however, I know quite a few religions and the tenets of those belief systems extremely well. To the best of my knowledge, almost all religions have the concept that their god is everywhere and everything; they believe that their god *is* the universe *and* exists as independent entity.
I am not familiar with the concept that you stated. In what religion may I find it? I will enjoy reading about it and deepening my understanding of the world’s religions.
It’s a true shame that the Webmaster of this site has eliminated the option of modifying our own posts. Even though I had carefully proofread my post, I just came back to it and saw at least two mistakes:
1. willingnes — typo
2. However, changes that occur within one species does — should be “do” I was thinking and typing too fast to remember the basic grammar of English.
If anyone finds any others, please let me know.
I am not sure how prevalent panentheism is in Jewish communities.
The Baha’i holy texts directly state that, though God is reflected in all parts of His creation, He is not His creation.
No, that’s not what I was saying. I was trying to say that you shouldn’t treat any and all ideas as true by default, and then later weed them out as they are falsified. For example, you should not believe in homeopathic medicine, ESP, or the Flying Spaghetti Monster up until the point where you have disproved them to your satisfaction. While some, like homeopathy, can be generally shown to be false or, like ESP, have no well verified cases, things like the FSM can never be disproved. If you don’t reject any claims that haven’t been disproved, then you are stuck believing all unfalsifiable things, like the FSM. Thus, instead of starting out credulously believing everything you hear someone say is true, all claims should be approached skeptically, and the objective evidence for whether it is the most probable explanation should be used before you provisionally accept something as true. Once you accept something as being provisionally true, you should still be willing to accept other evidence later on that would disprove it.
This may seem obvious, but some people have exceptions to this rule, claims that they accept without evidence, regardless of more probable explanations, and despite unfalsifiability.
Right, but I’m just saying that accepting things as true by default, and then having to disprove them before you stop thinking of them as true, is an irrational and unworkable way of thinking. Regarding the above example, it could only happen if evolution is flawed, but it wouldn’t disprove all of evolution. We still know, for example, that insects and germs can and do evolve to survive pesticides and antibiotics, respectively. The “rabbit” wouldn’t disprove that part of evolution, but it would put other things into question.
I would say the method of science is to attempt to prove hypotheses wrong for the purpose of weeding out errors. The reason for that is not to prove itself wrong, but to make sure it’s right by seeing if it could be wrong.
Just to make my opinion clear, I too am an atheist, but regarding evolution, while I have some doubts about a few of the specifics, in general I have little doubt that it is a sound scientific theory. In fact, few scientific theories that cannot be proven mathematically have such a mountain of confirming data from so wide variety of sciences.
Actually, there are, for example, quite a variety of crocodile today, plus a number of known extinct species, including Sarcosuchus imperator, which lived about 110 million years ago and grew up to 40 ft. (12 meters) long! I’m not sure I’d say they’ve not changed much, though I guess that depends on what you count as “much”.
Still, there is a rather simple explanation for a species existing for long periods with little evidence of evolution: a local maxima. In other words, as the genes are currently, any, normally small, genetic change can only make things worse. There is no room for improvement without a dramatic change, and that is something that is highly unlikely to occur successfully at random. Even if it did, it would also have to be passed successfully to multiple offspring, because half a change would still be bad.
To put it another way, they’ve evolved into a dead end, and they’d have to go too far back to take another path. That’s not to say that their design is bad, in fact, it actually means it’s pretty good if they’ve survived this long. However, unless the species’ environment changes a lot for a couple of million years, the odds are quite small that a species in a local maxima will ever evolve into something much different than it is at that point.
Well, considering that, for the most part, only bacteria, insects, and other short-lived organisms reproduce fast enough to evolve significantly “in modern time” that certainly limits the number of improvements one might expect to see. And considering the complexity of biology, defects will be far more common than improvements. However, improvements have occurred. Bacteria have evolved resistance to antibiotics, insects have evolved resistance to pesticides, and selective breeding has produced an amazing variety of dog species with various improvements and wheat crops that produce higher yields and are more resistant to disease.
Finding a “mate with a similar change” is only required if the gene is recessive. If the gene is dominant then all offspring will also have the trait. Even if a trait is recessive, if that trait helps the organism expressing that trait have more offspring than others of the species, that increases the ratio of that gene appearing in the population, thus increasing the rate at which it may be expressed again in later generations, etc., etc., until it becomes common in the population.
Actually, while some specifics will always elude us, we can know reasonably well what happened in general millions of years ago. We can not only look at fossils (which are objective evidence of evolution,) but we can compare the genes of existing species and tell approximately when the different species had common ancestors. Fossils and genetic information are two different sources that can be used to verify and test against each other.
The solution to that question already exists, and it is yes. Read this:
TalkOrigins: 29+ Evidences for Macroevolution
If you start off with false premises then you can prove anything (“Let’s assume that if the moon is made of cheese then the cow jumped over the moon, and that the moon is made of cheese. Now what have we proved?”) Change does occur within species, changes occur constantly and are fairly random, but generally the change of the species as a whole is not quick, which is why many species do die out.
Just to note, evolution does not require mutation for evolution to occur, a change in the dominance of existing genes is also an example of evolution.
While there have been found a few examples of something like this, like bacteria with “fragile genes” that are capable of activating “dormant” traits when under environmental stress, the vast majority of evolution does not appear to work this way. Some traits may be normally rare in a population, and then become more common when the environment changes and makes those traits more useful, however, which is similar to what you describe.
But when we compare, for example, the genes of humans and chimpanzees, we see that most of the changes are not that different genes are activated or deactivated, but that there are dramatic changes in genes. For example, we have one fewer pair of chromosomes and many genes were inserted, deleted, rearranged, or, most commonly, duplicated. They have found at least one allele so far that appears to be unique to humans as well. (see here)
In short, evolution is far more than turning on and off “dormant” genes. Even if your theory were true, it begs the question of where those genes came from in the first place if no other evolution occurs. The fossil evidence supports evolution from single-celled to more complex multi-cellular life, but your theory would require all of the genes for life that wouldn’t exist for billions of years be there right at the beginning in the first cells. This seems to create problems, rather than explain the evidence.
There is no “proof”, only further evidence for or against a claim. Examining the fossil record is a way of testing, verifying, and correcting the theory of evolution, and so far no fossils have been found that shed much doubt on it.
Actually, genetic “changes that occur within one species” is the definition of evolution. There is no such thing as “false” evolution, so I don’t know what you mean by “true evolution”.
No, evolution is not a “permanent” change in a species, it is merely a change. It may or may not be permanet, and is not required to be permanet.
Actually it is applicable, because it is the simplest explanation that fits the evidence, and your explanation does not do the latter, nor does it explain much of the other evidence, such as where those genes came from, which suggests it may actually be more complicated because that unexplained data will need another explanation or explanations.
Seriously: I believe in God simply because it feels right – but there is only one reality, and if science and dogma collide, that dog(ma) is dead!
On the other side, I really do have the FSM bumper sticker and magnet – I don’t always have to be dead serious about religion: if God created us, then He’s the one who gave us a sense of humor too. :-)
Is it too late to get a none-evolution-related comment in here?
Carol, I’d like to thank you for writing this article. I had to bring in a cell related article for class, and because of the poetic writing, I was able to perform it like a monologue. The entire presentation went over wonderfully. Thanks!
Also, last comment.
What a fantastic article.
Over multiple generations and many millions of years, it is amazing to learn how selection determines specialization and survival.
Wow. Well, well written.
Oh, just give me a break.
Are you serious? Your comments are so overly over-answered and proven to be fallacious as to be a waste of time. Unless you are a child in need of education.
Lighten up, Francis.
I love these critters! When I was in college, way back when, we actually had them in a lab class and got to watch the slugs slime around and react to various stimuli. We were taught that the slug is called a “grex”. Great name, eh?
Thanks for reuniting me with my old buddies, Carol!
Carol, I enjoyed your article, I had no idea these little guys lives such complex lives. As for Creationism, I always get a chuckle when creationists attack the theory of evolution by asking for proof. I know what would happen if they asked their priest for proof of creationism…
In scientific usage, a theory does not mean an unsubstantiated guess or hunch, as it can in everyday speech. A theory is a logically self-consistent model or framework for describing the behavior of a related set of natural or social phenomena. It originates from or is supported by experimental evidence (see scientific method). In this sense, a theory is a systematic and formalized expression of all previous observations, and is predictive, logical, and testable. In principle, scientific theories are always tentative, and subject to corrections or inclusion in a yet wider theory.
Creationists call us to believe the Biblical creation story as a literal account of historical events. However, Genesis contains two distinctly different creation accounts. Which creation story are they calling us to “literally” believe?
For generations, serious students of Scripture have noted stark divisions and variations in the age of the Hebrew, its style and language within Genesis. As we have it now, Genesis is actually a composite of three written primary sources, each with its own character, favorite words and distinctly different names for God. Such differences all but evaporate when translated into English, but they are clear in the ancient Hebrew text.
The first creation account, Genesis. 1:1 to Genesis. 2:4a, was written during or after the Jews’ Babylonian captivity. This fully developed story explains creation in terms of the ancient near eastern world view of its time. A watery chaos is divided by the dome (firmament) of the sky. The waters under the dome are gathered and land appears. Lights are affixed in the dome. All living things are created. The story pictures God building the cosmos as a supporting ecosystem for humanity. Finally, humanity, both male and female, is created, and God rests.
The second Creation story, Genesis 2:4b to 2:25, found its written form several centuries before the Genesis. 1:1 story. This text is a less developed and much older story. It was probably passed down for generations around the camp fires of desert dwellers before being written. It begins by describing a desert landscape, no plants or herbs, no rain; only a mist arises out of the earth. Then the Lord God forms man of the dust of the ground, creates an oasis-like Garden of Eden to support the “man whom he had formed.” In this story, God creates animal life while trying to provide the man “a helper fit for him.” None being found, God takes a rib from the man’s side and creates the first woman. These two creation stories clearly arise out of different histories and reflect different concerns with different sequences of events. Can they either or both be literal history?
And it came to pass eventually that this life form diversified, not confining themselves to cAMP, which was perhaps more useful than just a signaling system. Many subtle steps were involved, and during that time, the slime was not always benign. They mixed cooperation with aggression. They adapted to use other similar chemical compounds like adenosine di phosphate and adenosine tri phosphate, which some of us have given the nicknames ADP and ATP not just to signal one another, but to do WORK. They invaded other, bigger creatures, which up to that time were pretty lazy, and laid around and goofed off a lot. These complex beings were unable to rid themselves of the slimy little invaders that had snatched their bodies, cell by cell.
And that is how it came about that we got our most important and energetic slaves, slaves that can no longer escape their fate (until we die). We call them mitochondria.
Almost right. First of all, ameobas have mitochondria. They wouldn’t be so lively without them. Secondly, “bodies, cell by cell”? Unless I’m mistaken, there were no multicelled lifeforms before mitochondria.
I’m supprised that Carol didn’t mention the most remarkable thing about the ameoba. They reproduce asexualy. Pretty much, any ameoba you see is a copy of the first one – which is to say that it is the first one. They never age and are about 4 billion years old!
Thank Tom Robbins for that observation
I like your comment Mr. Disgruntled.
However, the record is unclear exactly when the mitochondria came aboard the amoeba. What are the chances that it was the very first amoeba that was discovered and invaded successfully by an ambitious and predatory mitochondrium? Or among the first quadrillion?
Perhaps I wasn’t clear. The case of the first mitochondrium parisiticly invading and/or being eaten and not digested happened long before the amoeba came along! Amoeba are late comers to the party.
By the way, mitochondria are not the only plastids created from endosymbiotic critters. Cloroplasts are too! There is even something called a Hatena arenicola (hatena translates roughly into “WTF?!”) that starts out life as an animal and ends up a plant when it injests the right cloroplast.
I must appologise for two things. First, I was mistaken. Amoeba are immortal normaly, but not always. Secondly, I must appologise for ruining the pemise of the article.
As I said, amoeba are normaly immortal, but when starved, they start to age. Thereafter, they divide assymetricly. The daughter cells start off immortal while the mother cells continue to deteriorate. Even if the cells find food without having to form spors, the mother cells are doomed to old age and death! Incedently, yeast always divide assymetricly when it comes to age. Anyway, there is no sacrifice involved. The old cells grow old and die and the young stack up the bodies in an attempt to excape. cAMP isn’t a signaling phermone, it’s the smell of age. The amoeba come together because they know there will soon be dead to stack. As the daughter cells have starved, escape still means death for them, as they too will grow old and die. It is their daughters who will become immortal.
Actually, in the entire body of the article, and in all the comments, yours is the first and only mention of immortality.
Also in my little parable, I never even used the word amoeba. I spoke in more general terms.
The rest of your response is something of a mixture. It meanders around some glinty words and fragments of facts. Some of those fragments can grow up to play a part in the formation of a larger picture. Some of them could point the curious toward interesting ideas. It is easy to lose track of the focus, the main thought that you are trying to put across. If you lose track of it, certainly the reader will too. That will put the reader asleep. Time for my nap.
nice article. gotta love those single/multi celled organisms.
I last posted about 11.5 years ago? Hard to believe.