Evolution of Complexity: Can Organisms Develop Immunity to Drugs Over Time?

[Gold Barz]

Do you think that given time, organisms become more and more complex no matter how slow the evolution of complexity is, organisms do get more complex over time?

 

[kalladin]

I don't believe that.. but I could be wrong. It really depends on the environment and how chance shapes that environment, simultaneously shaping how the organism accumulates mutations.

 

[Gold Barz]

How about, an ever-changing environment plus time equals increased complexity?

 

[Gold Barz]

Its not really chance, its more like whichever species becomes more adaptable to that environment live on

 

[selfAdjoint]

Evolution shapes the organisms to fit their environment, but that does not necessarily mean more complexity. The greatest mass of living organisms is still today in the bacteria; from that point of view, the whole mammalian evolution, including us, is just a minor fluctuation!

 

[Gold Barz]

But don't you think that given time creatures like animals would arise?

 

[gerben]

When all the niches for the "simple" organisms are filled there would still be possible niches for more "complex" organisms. If you believe that it is possible for more complex organisms to evolve from more simple organisms, its seems inevitable that at some point more complex organisms would arise that fit into one of the unexplored niches and would therefore flourish. A major step from simpler to more complex organisms seems to have taken place during the so-called "cambrian explosion".

http://www.fossilmuseum.net/Paleobiology/CambrianExplosion.htm

 

[Gold Barz]

So given time do you think these simple-life "niches" would eventually be filled and that would pave the way for more complex life?

 

[gerben]

just replication with small errors (this would lead to offspring different from its progeny that could fill an unfilled niche)

 

[Gold Barz]

So does this mean that "explosion" was caused by the filled niches of the more simpler organisms?

 

[gerben]

It is a huge debate what was the cause of the enormous increase ("explosion") of many complex multicellular organisms in the cambrian period. I just meant to say that there seems to have been "room" for multicellular organisms so once they arose they had ample "room" to stay. I did not mean to say that multicellular organisms are caused by the fact that niches for unicellular organisms were filled, but just that there were many unoccupied niches that could be filled by multicellular organisms.

(It is a palaeontological finding that many multicellular species first appeared during a short period about 550 million years ago which is called the cambrian period, that is why that period is sometimes referred to as the "cambrian explosion")

 

[Gold Barz]

I just meant to say that there seems to have been "room" for multicellular organisms so once they arose they had ample "room" to stay.

So do you think over time complexity will eventually arise, somewhere? I am talking about one planet.

 

[gerben]

yes if the condition are right, but I would not know what the conditions would have to be exactly...

I know it is not a very satisfying answer, but I do not a better answer.

 

[Gold Barz]

Like if the environment is complex?

 

[gerben]

Yes, I guess so.
The planet should be chemically complex enough to offer a possibility of any from of life to arise. I guess there should be water and lots of reactive/interacting chemicals.

 

[Gold Barz]

In another thread I asked if single-cell to multi-cell was an inevitability, you responded with:

Yes, I would think so. Given that there are already single celled organisms that are dividing and moving away from each other in order not to compete over the local resources. I guess it is inevitable than often things go wrong so that they cannot get away from each other for example because of a mutation they may stick to each other after division. When this occurs they may be worse off than their free conspecifics, but in some of the many cases in which this happens it will happen to a pair that will work better together than that any of them would work alone.

Another way would be that two different species both have an advantage of being close together (the use different nutrients so they do compete), perhaps the waste of the one is food for the other or one changes the local environment that aids the nutrient intake of the other. After a while pairs of them that stick together may arise and because they are good at finding nutrients they will produce much offspring so more and more of these will arise.

Could you elaborate me please

Thanks a bunch.

 

[selfAdjoint]

There is not always a path from the state of the organism to the possible niches in the environment. It is not inevitable that the descendents of worms will learn to fly, or to read!

Gould, in the last section of his book Wonderful Life! paints a picture of a sort of air mattress organism that could have come to dominate Earth's biosphere and given the slowness of any developments from a single organism, the sun would have gone red giant before anything interesting evolved.

 

[Gold Barz]

You guys sure do look at the bright side of things huh?

But yeah complexity might sometimes not be assured, but in our case (the only case we know of) it was/is.

 

[gerben]

In another thread I asked if single-cell to multi-cell was an inevitability, you responded with:
.....
Could you elaborate me please

I was just describing a few ways in which unicellular organisms could give rise to multicellular ones. Since I can think of ways in which this could occur and can also imagine that the multicellular organisms have ample opportunity to flourish when they are formed, this lead me to guess that given enough time it was inevitable that they would arise.

I guess the most important path is the path in which a single cell organism divides and the descendants stay together, and divide again and again. They all stay together forming a colony. Living in such a colony provides opportunities for functioning in different ways than when living alone, so some may specialize and be only able to perform a specific function and rely on the work of other cells in the colony for other things that are important for their survival. They may acquire capabilities of influencing neighboring cells in the colony (by releasing chemicals). After time these specialized cells may not be able survive on their own anymore. Now and then cells are released from the colony but these cells have now such a make-up that whenever they are alone they start dividing and dividing until they have formed a colony and then the individual cells within the colony start releasing chemicals influencing the others in their surrounding to specialize.

At this stage the colony looks like a multicellular organism. It starts with one cell that through many divisions provides all the cells for the colony (organism) and then each cell specializes to perform one specific function. All these cells will have the same DNA so they all possesses the tendency to form a colony and influence their neighbors in the colony in specific ways. So the whole “behavior” of the cell (the forming of a colony etc.) will aid in the replication of this DNA in new colonies. So you now have a system that is guided by its DNA to produce more copies of itself, which also have this DNA and thus will also make more copies etc. so you now have a multicellular organism.

It is interesting to note that still nowadays the life cycle of multicellular organisms go through a unicellular stage. It starts with it. It is a bit more complicated because most species have developed two sexes, but anyway most organisms start as one cell that keeps dividing and specializing until the body of the organism is formed. In some “simpler species like for example sponges small pieces of the sponge can break of to form a new sponge or even single cells can be released by the sponge that from a new sponges.

 

[nipwoni]

An interesting case is where a complex organism evolves into a seemingly more simple organism. For example, in the plant knigdom, for hundreds of millions of years there were no flowering plants. All plants that had seeds grew them in cones or conelike structures (the conifers and related groups). Cones are always pollinated by the wind. Wind pollination is not very efficient because the plant has to send out huge amounts of pollen that will randomly float around on the wind and maybe happen to land on a cone of the same species.
Then one group developed a new adaptation, flowers. These allowed pollen to be carried by specific pollinators (often insects), which greatly improved a plant's chances of getting its pollen to the seed of another plant of the same species. This adaptation was so successful that nowadays the vast majority of plant species have flowers. Scientists consider flowering plants more complex and advanced than others.
But later after the development of flowers, a new group of plants emerged called the monocots. These plants usually have greatly reduced flowers which are not meant to attract pollinators. In fact most monocots are pollinated by the wind. (There are still other monocots that are insect pollinated) They are simpler in other ways too, and their entire body plan is simpler than other flowering plants. Still, they are considered the most advanced of all plants. It seems strange to me that they would be called advanced because they have lost "unnecessary" complex parts, when other plants that never developed these things are considered primitive just because they evolved long before.

 

[Picklehead]

What you just said brought to my mind Saculina, a type of crustacean that has 'devolved' into a small sac-like structure of no more than a handful of cells, is a parasite of crabs, and looks superficially like a weird kind of internal fungal infection in its adult form.

But, yeah . . . with time you get complexity, if it's adaptive.

 

[gerben]

An interesting case is where a complex organism evolves into a seemingly more simple organism. For example, in the plant knigdom, for hundreds of millions of years there were no flowering plants. All plants that had seeds grew them in cones or conelike structures (the conifers and related groups). Cones are always pollinated by the wind. Wind pollination is not very efficient because the plant has to send out huge amounts of pollen that will randomly float around on the wind and maybe happen to land on a cone of the same species.
Then one group developed a new adaptation, flowers. These allowed pollen to be carried by specific pollinators (often insects), which greatly improved a plant's chances of getting its pollen to the seed of another plant of the same species. This adaptation was so successful that nowadays the vast majority of plant species have flowers. Scientists consider flowering plants more complex and advanced than others.
But later after the development of flowers, a new group of plants emerged called the monocots. These plants usually have greatly reduced flowers which are not meant to attract pollinators. In fact most monocots are pollinated by the wind. (There are still other monocots that are insect pollinated) They are simpler in other ways too, and their entire body plan is simpler than other flowering plants. Still, they are considered the most advanced of all plants. It seems strange to me that they would be called advanced because they have lost "unnecessary" complex parts, when other plants that never developed these things are considered primitive just because they evolved long before.

They are just called more "advanced" because they are a relatively new branch of the dicots (dicotyledons). Of course a specific modern day dicot species may seem more complex than some modern day monocot species. I agree that "advanced" is not a very appropriate term, it would be better to just call them "more modern".

It is just a matter of time of origin: first gymnosperms, than angiosperms, but first dicot angiosperms and then monocot angiosperms. However I would not think that a present day spruce is less "advanced" than an oak.

 

[gerben]

What you just said brought to my mind Saculina, a type of crustacean that has 'devolved' into a small sac-like structure of no more than a handful of cells, is a parasite of crabs, and looks superficially like a weird kind of internal fungal infection in its adult form.

But, yeah . . . with time you get complexity, if it's adaptive.

Sacculina is an interesting parasite, but I would not consider parasites simple. In any way they need other animals to exist and their life cycles are often quite sophisticated.

Ah, I found this great article "Do Parasites Rule the World? (an article by Carl Zimmer published in Discover 2000)"
http://www.alignment2012.com/ZapCoastDoParasitesRuletheWorld.html

How about this remarkable life cycle:

The mature lancet fluke, Dicrocoelium dendriticum, nestles in cows and other grazers, which spread the fluke's eggs in their manure. Hungry snails swallow the eggs, which hatch in their intestines. The immature parasites drill through the wall of a snail's gut and settle in the digestive gland. There the flukes produce offspring, which make their way to the surface of the snail's body. The snail tries to defend itself by walling the parasites off in balls of slime, which it then coughs up and leaves behind in the grass.

Along comes an ant, which swallows a slime ball loaded with hundreds of lancet flukes. The parasites slide down into the ant's gut and then wander for a while through its body, eventually moving to the cluster of nerves that control the ant's mandibles. Most of the lancet flukes head back to the abdomen, where they form cysts, but one or two stay behind in the ant's head.

There the flukes do some parasitic voodoo on their hosts. As the evening approaches and the air cools, the ants find themselves drawn away from their fellows on the ground and upward to the top of a blade of grass. Clamped to the tip of the blade, the infected ant waits to be devoured by a cow or some other grazer passing by.

If the ant sits the whole night without being eaten and the sun rises, the flukes let the ant loosen its grip on the grass. The ant scurries back down to the ground and spends the day acting like a regular insect again. If the host were to bake in the heat of the direct sun, the parasites would die with it. When evening comes again, they send the ant back up a blade of grass for another try. After the ant finally tumbles into a cow's stomach, the flukes burst out and make their way to the cow's liver, where they will live out their lives as adults.

 

[juju]

Hi,

Time only equals complexity if evolution is preceding in an environment where adaptive pressures confer a survival advantage on more complex organsims.

juju

 

[Gold Barz]

But don't most environments go by the slogan "only the strong survive"?

 

[matthyaouw]

Strong is a relative term. I'd say only the best adapted survive, and depending on the nature of the environment, sometimes simple, and sometimes complex organisms will dominate. Some of the simplest organisms around are eukaryotes(sp?)- cells without nuclei such as bacteria, and ecological nieches still exist where they dominate over all else. Humans themselves provide a number of homes for such organisms (there will be a good couple of kilograms of the things in your gut).

 

[iansmith]

Some of the simplest organisms around are eukaryotes(sp?)- cells without nuclei such as bacteria, and ecological nieches still exist where they dominate over all else.

It's prokaryotes, eukaryotes are the one with the nuclei. the term prokaryotes refers to the bacteria and archea but the term is not a proper classification/description of the group.

 

[matthyaouw]

Oops sorry. Its been a while since I last did biology.

 

[Phobos]

Gold Barz - S.J. Goulds book "Full House" talks a little about increasing complexity. As selfAdjoint correctly pointed out, the majority of life on Earth after 4 billion years is still bacterial. But also, early life likely started at the most basic (simple) level, so variations had to either be a lateral change (different kind of simple creature) or an increase in complexity. Becoming less complex than the minimum requirements for self-replication was not possible.

But don't most environments go by the slogan "only the strong survive"?

Perhaps you're thinking of "survival of the fittest" which is just a bumper sticker slogan referring to Darwin's Natural Selection (that slogan does not fully represent all the components of Darwinism).

 

[Gold Barz]

But also, early life likely started at the most basic (simple) level, so variations had to either be a lateral change (different kind of simple creature) or an increase in complexity. Becoming less complex than the minimum requirements for self-replication was not possible.

Thats my point, I think given enough time you will see an increase in maximum complexity of atleast one kind of life, if not more, don't you agree?

 

[misskitty]

Wouldn't immunity be another way to become more complex?

 

[Phobos]

Thats my point, I think given enough time you will see an increase in maximum complexity of atleast one kind of life, if not more, don't you agree?

Yep, I think we all agree that complexity can increase over time...I think we're just being careful not to imply that a certain degree of complexity (or a certain direction) is a necessary outcome or that all life will do this (since most life is still less "complex").

Wouldn't immunity be another way to become more complex?

Certainly. Competition with other species, particularly species that directly attack you, is a great way to ramp up natural selection. Not that N.S. creates complexity...rather it can more quickly sort through the existing variations of a population and bring better-adapted (e.g., better immunity) traits to the forefront of the population.

 

[Gold Barz]

Yep, I think we all agree that complexity can increase over time...I think we're just being careful not to imply that a certain degree of complexity (or a certain direction) is a necessary outcome or that all life will do this (since most life is still less "complex").

I sincerely think that complexity probably/likely increases over time. But the number of more complex life will narrow while it's complexity increases, don't you think?

 

[misskitty]

Certainly. Competition with other species, particularly species that directly attack you, is a great way to ramp up natural selection. Not that N.S. creates complexity...rather it can more quickly sort through the existing variations of a population and bring better-adapted (e.g., better immunity) traits to the forefront of the population.

I know that there are certain strains of viruses or illnesses that the human race has become immune to...or most of it. That would mean that the human race continues to grow in complexity, wouldn't it?

 

[misskitty]

I sincerely think that complexity probably/likely increases over time. But the number of more complex life will narrow while it's complexity increases, don't you think?

Maybe. There will porbably always be a spectrum of least to most complex. It might narrow a little bit. I can't see it narrowing by much though.