How did evolution get it right?

[callmeclean]

Hello. I have always been confident in the fact Evolution based on the few bits of evidence I knew about and logical reasoning. However it is only recently it has started to amaze me even more, probably because of my studies of the complexity of the human body at school. And so I have started to read further into it.

This is a question focused specifically to the Natural Selection aspect of Evolution.

 

An organism that has a feature better suited to its environment that allows it to function will survive, while an organism that does not will die. And we see this everywhere, it is the whole basis of survival of the fittest. And the fact that the few organisms with these suitable features survived and the many without them did not is used as evidence for evolution.

So it is unintelligence design (to quote Dawkins) that determined the species better suited is the species that survives. However what is it that determines that any organism has a feature like that in the first place. It is a near impossible chance that some organisms slowly gained legs and managed to crawl onto land. Why didn't they all just not develop legs and be stuck in the water or die on land. And the fact that something so suited to an environment seems to develop again and again seems absolutely amazing.

 

So I really want someone to give me an idea of how this might happen. The best I can come up with is food supplies run short in an area of water and the creature is forced further and further into new areas, including land. Maybe only a few with a strange extruding blob of some sort could slightly drag themselves up and gather some food off the shore and then back into the water. And as generations went on these fish with strange blobs were the ones that survived, and the blob genes changed randomly and after generations again one with a slightly bigger blob went further into land. But then how does the chance of having a skeleton come into this? The fact that we have a skeleton, a completely impossible thing, to support our limbs and body, a completely impossible thing. And I assume there was a period of a species that could breath in both water and on land that allowed for this transition of habitat.

 

As you might tell I don't know much, and a lot of what I say might seem a bit ignorant. But I am new, and if you could try and explain this idea to me that would be great. If it's just a wall of words, I guess what I am asking is this: Evolution is not reactive, the organisms that nature gets wrong die off, but how did so many seemingly get it right for their specific habitat in a universe of infinite possibilities.

 

Thank you.

Edited August 6, 2012 by callmeclean

[CaptainPanic]

It is a near impossible chance that some organisms slowly gained legs and managed to crawl onto land.

They did though.

 

This wikipedia website is about "tiktaalik", which is one of the many animals which started to adapt to leave the water. On the same page, you will find several other links to other animals that were either more or less adapted.

 

One of the best examples of how fish could evolve legs is Panderichthys, (also mentioned on that wikipedia site), which had fins adapted for mud and shallow water. This creature couldn't actually leave the shallow water yet.

[callmeclean]

They did though.

 

This wikipedia website is about "tiktaalik", which is one of the many animals which started to adapt to leave the water. On the same page, you will find several other links to other animals that were either more or less adapted.

 

One of the best examples of how fish could evolve legs is Panderichthys, (also mentioned on that wikipedia site), which had fins adapted for mud and shallow water. This creature couldn't actually leave the shallow water yet.

 

Thanks. I guess that narrows it down one further. From water, to more muddy and shallow waters and then land. And I suppose one of the things scientists in this area are able do after finding evidence such as fossiles is to narrow down these transitional stages between species even further.

 

The fact that it did happen I realise. However the extent to which seems impossible. Although I am not expecting a definite answer, I was thinking maybe there would be some more speculation and hypothesis' around the subject. Or maybe not.

 

On a similar note, the complexity of the body which many may lazily credit a god for does seem somewhat reactionary. Not in the way of intelligent design. But rather than just Natural Selection, it seems from the way the body is designed that it does not just have successful features but knows what these features are and do and can therefor successfully build upon them. Definitely not in a conscious way, but there may be a reactive component in the evolution of life that could explain these seemingly impossible feats it accomplishes. Anyway just a thought.

[StringJunky]

It is a near impossible chance that some organisms slowly gained legs and managed to crawl onto land. Why didn't they all just not develop legs and be stuck in the water or die on land.

Thank you.

 

Rythmic tidal forces on the oceans between the Sun/Moon and Earth would have caused some early organisms on shorelines to be regularly exposed to the free atmosphere when they were beached on the down tide...they most likely didn't crawl onto land initially; they were exposed by the sea receding. If those tidal forces didn't exist Earth's inhabitants might have stayed purely aquatic because I don't think there would have been sufficient selection pressure to adapt: what would be the need to crawl out of the water?

 

The regular exposure to free atmosphere would have allowed some organisms, which had beneficial mutations that aided locomotion under those circumstances, to have greater reproductive success because there would have been less competition.

 

If you notice, organisms did not move from water to land in one go....they were periodically exposed to the free atmosphere giving plenty of opportunity for organisms to adapt eventually to inhabit dry land.

 

Evolution occurs in very small steps over a very long time.

Edited August 6, 2012 by StringJunky

[callmeclean]

If you notice, organisms did not move from water to land in one go....they were periodically exposed to the free atmosphere giving plenty of opportunity for organisms to adapt eventually to inhabit dry land.

 

Evolution occurs in very small steps over a very long time.

Yes but what I am wondering is how they adapted. Being exposed to the free atmosphere periodically does not affect the chance of being able to breath in oxygen when in that atmosphere unless there a reactive aspect of evolution. And the probability that an organism by chance gained this ability to breath in is very slim, and the fact that it seems to have happened over and over again in different cases seems near-impossible.

 

As I said before, I'm not very knowledgable in this. But I have been learning about Epigenetics recently. So maybe this process or a similar one could have influence on evolution. Obviously it would seeing as certain chemicals in the environment affect the inheritable gene, such as cancer causing carcinogen's. But to what extent? So maybe there is something in the atmosphere that had a certain affect on DNA that eventually evolved into (over a very long period of time), or helped in the evolution of, an ability to breath in that atmosphere.

 

Just throwing out an idea. It's all very fun and interesting to think about.

 

 

 

[StringJunky]

Yes but what I am wondering is how they adapted. Being exposed to the free atmosphere periodically does not affect the chance of being able to breath in oxygen when in that atmosphere unless there a reactive aspect of evolution. And the probability that an organism by chance gained this ability to breath in is very slim, and the fact that it seems to have happened over and over again in different cases seems near-impossible.

 

As I said before, I'm not very knowledgable in this. But I have been learning about Epigenetics recently. So maybe this process or a similar one could have influence on evolution. Obviously it would seeing as certain chemicals in the environment affect the inheritable gene, such as cancer causing carcinogen's. But to what extent? So maybe there is something in the atmosphere that had a certain affect on DNA that eventually evolved into (over a very long period of time), or helped in the evolution of, an ability to breath in that atmosphere.

 

Just throwing out an idea. It's all very fun and interesting to think about.

 

I'm no expert either but find it interesting as well. I can't give you the steps leading to terrestrial locomotion or breathing free air but I am aware of some ideas about the evolution of the eye which gives some idea of the kind of transitional evolutionary phases necessary to reach a certain complexity.

[callmeclean]

I'm no expert either but find it interesting as well. I can't give you the steps leading to terrestrial locomotion or breathing free air but I am aware of some ideas about the evolution of the eye which gives some idea of the kind of transitional evolutionary phases necessary to reach a certain complexity.

 

Thanks for the link. Interesting, the idea that eyes (or their equivalent) developed many times independently.

Another thing I read "Sensory organs probably evolved before the brain did—there is no need for an information-processing organ (brain) before there is information to process." Is something I have never thought about before. I suppose that before consciousness there was pure instinct, which came about with the development of the brain. But even before just instinct alone there was organisms like bacteria, but maybe more advanced, that were purely reactive. They maybe had an eye-like device and were completely reactive without the slight bit of reasoning and help that instinct gives you. Anyway I will read further into this thanks.

[ewmon]

I just want to say that random mutations don't occur for any particular purpose. For example, a series of mutations might occur that develop limb-like parts or light-sensitive tissues on the roof of an animal's mouth, but if these mutations don't make the individual better suited for something, somehow better at surviving, better fitted to the animal's environment, then the individual is not more likely to survive and produce offspring with those same (or, again, or slightly mutated mutations) that furthers evolution.

 

At the same time that being lobe-limbed gave certain fish a mobility advantage to move onto land, I'm sure there were fish who were mutating other features that allow them to better survive in the water. There are mutations that don't seem to confer any better survival characteristics in an individual, but given some future mutation(s), the combination of mutations may allow a higher survival rate in a particular environment. Consider some Arabian horses that have five lumbar vertebra instead of the "normal" six for all other horses. It may not give those Arabians a particular advantage at anything, and may even given them a slight (but survivable) disadvantage, yet future mutation(s) may give an individual Arabian a significant advantage.

 

There's no "purposeful" direction that random mutations "seek". Mutations may very well (and, I think, most likely do) make an individual less fit to its environment, and results in it less likely to survive and produce offspring. If you study genetic algorithms, you can see more clearly how random software changes can sometimes lead to improvements (ie, better suited for a particular task), but that such random changes most likely result in "broken" computer code.

[callmeclean]

I just want to say that random mutations don't occur for any particular purpose. For example, a series of mutations might occur that develop limb-like parts or light-sensitive tissues on the roof of an animal's mouth, but if these mutations don't make the individual better suited for something, somehow better at surviving, better fitted to the animal's environment, then the individual is not more likely to survive and produce offspring with those same (or, again, or slightly mutated mutations) that furthers evolution.

 

At the same time that being lobe-limbed gave certain fish a mobility advantage to move onto land, I'm sure there were fish who were mutating other features that allow them to better survive in the water. There are mutations that don't seem to confer any better survival characteristics in an individual, but given some future mutation(s), the combination of mutations may allow a higher survival rate in a particular environment. Consider some Arabian horses that have five lumbar vertebra instead of the "normal" six for all other horses. It may not give those Arabians a particular advantage at anything, and may even given them a slight (but survivable) disadvantage, yet future mutation(s) may give an individual Arabian a significant advantage.

 

There's no "purposeful" direction that random mutations "seek". Mutations may very well (and, I think, most likely do) make an individual less fit to its environment, and results in it less likely to survive and produce offspring. If you study genetic algorithms, you can see more clearly how random software changes can sometimes lead to improvements (ie, better suited for a particular task), but that such random changes most likely result in "broken" computer code.

 

Ok so the environment affecting the genes is a pretty accepted theory I think. http://newswatch.nat...on_is_evolving/

I even learn it alongside polygenic inheritance at school. The mutations caused by the environment would have the same small chance of being beneficial to the organisms survival as random mutations do. Which shows the flaw in my logic so far; the fact that the environment does not have the logic to put the chemicals good for land adaption on the land. Now this is very hypothetical, just a crazy idea. If somehow there was a process of 'Natural Selection' for the mutation causing chemicals. Obviously not in the same sense of organisms, however the makeup of the atmosphere is not static, it does react and change over time and so do chemicals that are within certain areas I would assume. So maybe there is a possibility that often certain chemicals that aid a organism in adaption to a specific area, will be found mostly in the specific area. Obviously this is based on no evidence just a thought.

 

UV light from the sun is a carcinogen that can mess with the cells ability to make melanin, and melanin has the ability to protect us from UV light. I'm not sure if there is information on why this very relevant connection between the two, or if it has just been shown to be a completely isolated coincidence. I would be interested to know.

 

And now another thing has just popped into my head. I remember earlier from reading (http://en.wikipedia....tion_of_the_eye) that many organisms have developed 'eyes' things based on their common ancestors photosensitive proteins called opsins. (I didn't say it right I don't think) Maybe this could have something to do with the idea of Epigenetics. Where a high exposure to UV light might have increased the production of these opsin and therefor changed those effected cells function primarily to light sensing, and therefore would over time make the eye a more significant part of the organism as it is today. This might again show a deeper connection between the environment and the organism.

 

Anyway again just a bunch of ideas. Destroy them as you wish.

 

EDIT: So to reference one specific thing you said: "a series of mutations might occur that develop ... light-sensitive tissues on the roof of an animal's mouth..." Again from my very ignorant viewpoint, (I do find it hard to follow some of this stuff) Epigenetics might explain why the bulk or all of these light sensitive proteins are in a useful place making up the eye, rather than in random places where they are not as useful.

Edited August 6, 2012 by callmeclean

[Delta1212]

Ok so the environment affecting the genes is a pretty accepted theory I think. http://newswatch.nat...on_is_evolving/

I even learn it alongside polygenic inheritance at school. The mutations caused by the environment would have the same small chance of being beneficial to the organisms survival as random mutations do. Which shows the flaw in my logic so far; the fact that the environment does not have the logic to put the chemicals good for land adaption on the land. Now this is very hypothetical, just a crazy idea. If somehow there was a process of 'Natural Selection' for the mutation causing chemicals. Obviously not in the same sense of organisms, however the makeup of the atmosphere is not static, it does react and change over time and so do chemicals that are within certain areas I would assume. So maybe there is a possibility that often certain chemicals that aid a organism in adaption to a specific area, will be found mostly in the specific area. Obviously this is based on no evidence just a thought.

 

UV light from the sun is a carcinogen that can mess with the cells ability to make melanin, and melanin has the ability to protect us from UV light. I'm not sure if there is information on why this very relevant connection between the two, or if it has just been shown to be a completely isolated coincidence. I would be interested to know.

 

And now another thing has just popped into my head. I remember earlier from reading (http://en.wikipedia....tion_of_the_eye) that many organisms have developed 'eyes' things based on their common ancestors photosensitive proteins called opsins. (I didn't say it right I don't think) Maybe this could have something to do with the idea of Epigenetics. Where a high exposure to UV light might have increased the production of these opsin and therefor changed those effected cells function primarily to light sensing, and therefore would over time make the eye a more significant part of the organism as it is today. This might again show a deeper connection between the environment and the organism.

 

Anyway again just a bunch of ideas. Destroy them as you wish.

 

EDIT: So to reference one specific thing you said: "a series of mutations might occur that develop ... light-sensitive tissues on the roof of an animal's mouth..." Again from my very ignorant viewpoint, (I do find it hard to follow some of this stuff) Epigenetics might explain why the bulk or all of these light sensitive proteins are in a useful place making up the eye, rather than in random places where they are not as useful.

Re: placement of light sensitive cells

 

Let's say that you have a hypothetical organism that's sort of like a blind frog. Over the course of a million years, one thousand of these frogs develop a mutation for light sensitive cells, all in random places. Some get them on the roof of their mouth. Some get them on the bottoms of their feet. Some get them on top of their head.

 

The ones with light sensitive cells on the top of their heads are able to tell day from night as well as things like the shadows of birds passing overhead. This helps them avoid predators, so more of them survive. The ones with light sensitive cells on the bottoms of their feet receive no useful information from them and may even have the cells interfere with things like tactile sensation that are important on feet.

 

The population of frogs with "eyes" on the tops of their heads explodes while those with "eyes" elsewhere does not because they either do not help or actively harm the frogs chances of survival. Generations down the line, all of the frogs "somehow" have the mutation in the right place for it to help the most.

 

 

Looking at things now and marveling at the way all of the mutations had to be just right to build on each other and reach that point is a bit like marveling at a how someone could come up with the design for something that works as well as the stealth bomber because you can't see the numerous prototypes thatdudn't work or, going back even further, the hundreds of planes with ten rows of cloth wing or flapping helicopter blades that cropped up before a basic design to achieve flight was arrived at.

 

To get that one mutation that happens to work just the right way in just the right spot, you need to go through thousands or even hundreds of thousands of similar but ultimately very unhelpful mutations. In the end, the "wrong" mutations all die out or become very small subsets of the population while the "right" ones multiply because they help their "host" survive and reproduce. Then the next round of mutations will be working from that base.

 

Before we got fish with fins that were good at moving around on land, we would have had fish that had no fins, fish with fins growing out of their faces, fish with extremely thin and weak fins... They all died and the fish with the fins most helpful for moving around on land survived to reproduce.

 

That exact same mutation may have, and probably did, show up in places where the population of fish-things did not frequently get exposed to the land. In that context, it wouldn't be a miraculous mutation that will help lead to life on land. It's a birth defect that leads to a slightly awkward swimmer who gets bred out of the gene pool because it isn't useful.

 

The environment does not help cause mutations that will be helpful for surviving that environment. It simply kills off all the ones that don't so only the useful mutations get sustained into the next generation.

 

Edit: Actually, the reference to genetic algorithms is a good one. One of my very first programming projects was an evolution sim. I made little circles that I assigned a set of traits to in its "DNA" and allowed to make copies of itself when it reached a certain energy threshold obtained by eating food.

 

These traits included color, size, whether they ate the little green food pellets I generated on screen or other "animal" circles, sensors that detect colors and reactions that are triggered by these sensors firing which include changing speed and direction (either moving toward the detected object, away from it, or ignoring it).

 

All of these traits had a random probability of "mutating" when a circle replicated and being replaced with a different value. The first circle was just a little black circle that would move in a straight line randomly bumping into food pellets.

 

After many generations, though, I'd wind up with a variety of different survival strategies. For example, a particularly successful one that crops up sometimes is a circle that will move very slowly (to conserve energy) until something activates one of its sensors. If it is the color of food, it moves very quickly towards it. Otherwise, it moves very quickly away from it.

 

It seems a little magical when you do something like this for yourself and see emergent behavior that you didn't program arise, but it also helps you recognize that, if you pay enough attention to catch them before they disappear, you'll see plenty of circles that run away from food or directly at predators, just one or two values off of a far more successful version. It's not magic that creates the cool ones. It's just a lot of trial and error and very quickly chucking the designs that don't work in favor of those that do.

Edited August 6, 2012 by Delta1212

[Arete]

UV light from the sun is a carcinogen that can mess with the cells ability to make melanin, and melanin has the ability to protect us from UV light. I'm not sure if there is information on why this very relevant connection between the two, or if it has just been shown to be a completely isolated coincidence. I would be interested to know.

 

Chemicals can and do cause mutations which you can pass on to your offspring - acrylamide is mutagen we use in the lab that can result in male reproductive toxicity if it damage the genes in your gametes. http://www.sciencedi...890623802000783 If the acrylamide causes mutations in sperm or eggs, these mutations can be passed on to offspring, however the result is usually simply infertility.

 

However, for a chemical to do this, it needs to create mutations in gametic cells - as the cells in your skin are not going to be involved in reproduction, any accumulated mutations in them will not be passed on and therefore won't be spread through a population. Therefore, if UV causes mutations in your skin cells, it won't cause an impact on the human species as whole, as you would have no way of passing on those mutations.

Edited August 6, 2012 by Arete

[callmeclean]

Re: placement of light sensitive cells

 

Let's say that you have a hypothetical organism that's sort of like a blind frog. Over the course of a million years, one thousand of these frogs develop a mutation for light sensitive cells, all in random places. Some get them on the roof of their mouth. Some get them on the bottoms of their feet. Some get them on top of their head.

 

The ones with light sensitive cells on the top of their heads are able to tell day from night as well as things like the shadows of birds passing overhead. This helps them avoid predators, so more of them survive. The ones with light sensitive cells on the bottoms of their feet receive no useful information from them and may even have the cells interfere with things like tactile sensation that are important on feet.

 

The population of frogs with "eyes" on the tops of their heads explodes while those with "eyes" elsewhere does not because they either do not help or actively harm the frogs chances of survival. Generations down the line, all of the frogs "somehow" have the mutation in the right place for it to help the most.

 

 

Looking at things now and marveling at the way all of the mutations had to be just right to build on each other and reach that point is a bit like marveling at a how someone could come up with the design for something that works as well as the stealth bomber because you can't see the numerous prototypes thatdudn't work or, going back even further, the hundreds of planes with ten rows of cloth wing or flapping helicopter blades that cropped up before a basic design to achieve flight was arrived at.

 

To get that one mutation that happens to work just the right way in just the right spot, you need to go through thousands or even hundreds of thousands of similar but ultimately very unhelpful mutations. In the end, the "wrong" mutations all die out or become very small subsets of the population while the "right" ones multiply because they help their "host" survive and reproduce. Then the next round of mutations will be working from that base.

 

Before we got fish with fins that were good at moving around on land, we would have had fish that had no fins, fish with fins growing out of their faces, fish with extremely thin and weak fins... They all died and the fish with the fins most helpful for moving around on land survived to reproduce.

 

That exact same mutation may have, and probably did, show up in places where the population of fish-things did not frequently get exposed to the land. In that context, it wouldn't be a miraculous mutation that will help lead to life on land. It's a birth defect that leads to a slightly awkward swimmer who gets bred out of the gene pool because it isn't useful.

 

The environment does not help cause mutations that will be helpful for surviving that environment. It simply kills off all the ones that don't so only the useful mutations get sustained into the next generation.

 

Edit: Actually, the reference to genetic algorithms is a good one. One of my very first programming projects was an evolution sim. I made little circles that I assigned a set of traits to in its "DNA" and allowed to make copies of itself when it reached a certain energy threshold obtained by eating food.

 

These traits included color, size, whether they ate the little green food pellets I generated on screen or other "animal" circles, sensors that detect colors and reactions that are triggered by these sensors firing which include changing speed and direction (either moving toward the detected object, away from it, or ignoring it).

 

All of these traits had a random probability of "mutating" when a circle replicated and being replaced with a different value. The first circle was just a little black circle that would move in a straight line randomly bumping into food pellets.

 

After many generations, though, I'd wind up with a variety of different survival strategies. For example, a particularly successful one that crops up sometimes is a circle that will move very slowly (to conserve energy) until something activates one of its sensors. If it is the color of food, it moves very quickly towards it. Otherwise, it moves very quickly away from it.

 

It seems a little magical when you do something like this for yourself and see emergent behavior that you didn't program arise, but it also helps you recognize that, if you pay enough attention to catch them before they disappear, you'll see plenty of circles that run away from food or directly at predators, just one or two values off of a far more successful version. It's not magic that creates the cool ones. It's just a lot of trial and error and very quickly chucking the designs that don't work in favor of those that do.

 

 

Chemicals can and do cause mutations which you can pass on to your offspring - acrylamide is mutagen we use in the lab that can result in male reproductive toxicity if it damage the genes in your gametes. http://www.sciencedi...890623802000783 If the acrylamide causes mutations in sperm or eggs, these mutations can be passed on to offspring, however the result is usually simply infertility.

 

However, for a chemical to do this, it needs to create mutations in gametic cells - as the cells in your skin are not going to be involved in reproduction, any accumulated mutations in them will not be passed on and therefore won't be spread through a population. Therefore, if UV causes mutations in your skin cells, it won't cause an impact on the human species as whole, as you would have no way of passing on those mutations.

 

Thanks for me helping me get my head around it a bit better. I still have a lot of questions but thats the fun of it.

 

Seeing as you mention that program you made, I have heard a few people who have done it. I have some basic programming skills and might give it a go.

[akh]

Hello. I have always been confident in the fact Evolution based on the few bits of evidence I knew about and logical reasoning. However it is only recently it has started to amaze me even more, probably because of my studies of the complexity of the human body at school.

 

 

So it is unintelligence design (to quote Dawkins) that determined the species better suited is the species that survives. However what is it that determines that any organism has a feature like that in the first place. It is a near impossible chance that some organisms slowly gained legs and managed to crawl onto land. Why didn't they all just not develop legs and be stuck in the water or die on land. And the fact that something so suited to an environment seems to develop again and again seems absolutely amazing.

 

 

I suggest that you study developmental biology. Specifically, you should look into Hox genes and Hox proteins. These are the genes that control regulatory mechanisms. They can activate and repress genes. The important aspect in regards to morphology is that many of the differences we see in morphology from one animal species to the next are a result in changes in the Hox genes, changes in the regulatory mechanism of a gene and not the gene itself. This is why embryos of different animals look very, very, very similar.

 

I will try to give a simplistic model of how this works. Say you have a four legged animal. That animal has the genes that code for four legs/limb development. Then there is a Hox gene that regulates the expression of the genes that code for four legs/limb development. Say in one example the Hox gene has changed so that it has no function or very little function, and the genes for limb development do not turn on or are extremely limited. The result is that the animal does not grow any limbs, or growth is extremely limited (dolphin). Now in another animal, the Hox gene activates the gene for limbs but shuts off early in development of the animal. This animal ends up with stumps for legs, or flippers (a walrus). In another animal, the Hox gene triggers the genes for limb development late. In this animal, the limbs are short, but the appendages (fingers) end up being very long and webbed. This animal ends up wings for flight (bat wings). In another animal, the Hox gene switches on the genes for limb development early and these genes stay "on" throughout development and you end up with something like an ape, with long arms and legs and fingers.

 

Again, these are very, very simplistic examples and obviously many other changes occur. The important thing is that from flippered whale to human being, the changes are not in the genes for limb development per say, but in the Hox gene that regulates the limb genes.

 

There are other changes that can happen too, like a mistake during crossover of meiosis (prophase I) that results in one gamete with no limb gene and another with a double limb gene. In this individual, the double limb gene effectively produces double the factors for limb development, and you get offspring with longer limbs. Again, this is overly simplistic, there are many other things that come into play like feedback mechanisms and such.

 

So, you can get a surprising amount of changes in morphology not from a change in the gene for a specific characteristic, but rather from a change in where, when, how much a gene is expressed.

Edited August 7, 2012 by akh

[Tres Juicy]

 

The fact that it did happen I realise. However the extent to which seems impossible.

 

 

Roll a dice a billion times and record the outcome of each roll (Eg: Roll 1 = 3 roll 2 = 5.... Etc.) when you finish calculate the probability of getting the outcome you just got.

 

It will be such a miniscule probability that it could be said to be near impossible, yet it just happened.

 

The fact is, whatever the outcome, the odds were against it.

[dmaiski]

well if you’ve read Terry Pratchett , you will know that “Million-to-one chances crop up nine times out of ten.” ^.^

 

actually if you have sufficient data and processing power you can perfectly predict the future, but to perfectly predict the future you would need a computer larger then the universe it self

 

kinda lends weight to intelligent design,

an intelligent EVIL designer that was like a child with an ant farm, and a magnifying glass, bunch of needles, can of petrol, and a blowtorch

 

but back to serious discussion, if you read all there is to the theory of biological evolution

you would know that this eventuality was actually a very likely thing to happen,

because evolution likes to build bigger things, until they eventually collapse due to structural failure(like leg bones being too thin to support 100tone bodies)

so development of larger organisms is inevitable

 

the only thing that was slightly unlikely was the development of this specific form of chemical metabolism that we use

there are lots of other ways to skin that cat

 

 

[Joatmon]

You ask "How did evolution get it right?"

The fact is that it hasn't yet and never will, but it will keep on trying to find small improvements in its quest to "get things right".

[dimreepr]

well if you've read Terry Pratchett , you will know that "Million-to-one chances crop up nine times out of ten." ^.^

 

actually if you have sufficient data and processing power you can perfectly predict the future, but to perfectly predict the future you would need a computer larger then the universe it self

 

kinda lends weight to intelligent design,

an intelligent EVIL designer that was like a child with an ant farm, and a magnifying glass, bunch of needles, can of petrol, and a blowtorch

 

but back to serious discussion, if you read all there is to the theory of biological evolution

you would know that this eventuality was actually a very likely thing to happen,

because evolution likes to build bigger things, until they eventually collapse due to structural failure(like leg bones being too thin to support 100tone bodies)

so development of larger organisms is inevitable

 

the only thing that was slightly unlikely was the development of this specific form of chemical metabolism that we use

there are lots of other ways to skin that cat

 

 

 

 

It isn't about data and processing power, Heisenberg see's to that, predicting the future is just a dream, however deterministic our universe is or maybe. Larger organisms isn't what's inevitable, better fitting, as in environment, is all that's inevitable hence the word "evolution".

 

Edited September 19, 2012 by dimreepr

[dmaiski]

but larger is better fitting

 

if your larger, you can:

eat the smaller ones,

are less susceptible to destruction due to damage,

have space for redundant systems,

simply put have more of everything

MEANING you will out compete the smaller organisms

 

its like the arms race:

bigger is better

smarter is better

tougher is better

 

thus it is inevitable if you think about it in terms of natural selection

the "fittest" individual will become dominant

and being bigger is fitter, simply because the little things cant harm you as much

 

 

[dimreepr]

but larger is better fitting

 

if your larger, you can:

eat the smaller ones,

are less susceptible to destruction due to damage,

have space for redundant systems,

simply put have more of everything

MEANING you will out compete the smaller organisms

 

its like the arms race:

bigger is better

smarter is better

tougher is better

 

thus it is inevitable if you think about it in terms of natural selection

the "fittest" individual will become dominant

and being bigger is fitter, simply because the little things cant harm you as much

 

 

 

 

Not at all, think about bacteria and viruses. Larger isn't better, more effective is better and that doesn't depend on size or intelligence and tougher is relative.

 

Edited September 19, 2012 by dimreepr

[Joatmon]

Dinosaurs didn't do so well.

[akh]

but larger is better fitting

 

if your larger, you can:

eat the smaller ones,

 

 

This does not equate to fitness in a biological sense. You have failed to understand what fitness means, as was pointed out earlier.

 

 

if your larger...

are less susceptible to destruction due to damage,

 

Not at all true. Being larger does not make you more resilient. There are many small and simple organisms that can withstand extremes in environment (radiation, heat, cold, salinity) that would instantly kill more complex life forms. There are many "simple" organisms that can regenerate lost limbs; like starfish or earthworms. Can a lion or shark do that?

 

 

if your larger...

have space for redundant systems,

 

 

Again, not at all true. Do you have proof to back up this claim?

simply put have more of everything

MEANING you will out compete the smaller organisms

 

its like the arms race:

bigger is better

smarter is better

tougher is better

 

thus it is inevitable if you think about it in terms of natural selection

the "fittest" individual will become dominant

and being bigger is fitter, simply because the little things cant harm you as much

 

 

 

You have a very strong misunderstanding of fitness and what it means. You are comparing different species when using the term fitness. But fitness (biological terminology) can only be properly applied and determined for an individual within a population of the same species!

Edited September 20, 2012 by akh

[dmaiski]

i can back this up with simple logic

 

we have 2 creatures

one is an amoeba small single celled tiny

the other is a elephant

 

we take a hammer and hit both with said hammer repeatedly

the amoeba survives the first 25 hits, but eventually goes "splat"

the elephant survives the first 38 hits then gores and tramples out intrepid research intern

(the elephant is relevantly unharmed, the inters was weak, it has a small bruise in its side)

the intern also survives after 22 surgeries, and an extended hospital stay

 

yes it is an extreme example

but dose this get the point across

big things are harder to kill, because they are big,

as in bigger then you are, as in if you attach them you go "splat"

 

also you know what i meant, dont be petty, we can compare the fitness of two species, not mathematically, but conceptually

Edited September 20, 2012 by dmaiski

[Arete]

we have 2 creatures

one is an amoeba small single celled tiny

the other is a elephant

 

repeat the experiment by holding them underwater.

or removing the oxygen from the air.

or putting them in the freezer.

or putting them in boiling water...

 

amoeba are some of the most resilient creatures on the planet. Size is generally a poor indicator or how resilient an organism is.

[akh]

I am not being petty. You have not used the term correctly. The pettiness is firmly from your side. You can not compare fitness of two species mathematically or conceptually.

 

And your simple logic is still flawed. Last time I checked, hammers are not a natural occurance. There are multiple examples of how megafauna is actually the most vulnerable in the face of environmental pressures.

 

i can back this up with simple logic

 

we have 2 creatures

one is an amoeba small single celled tiny

the other is a elephant

 

we take a hammer and hit both with said hammer repeatedly

the amoeba survives the first 25 hits, but eventually goes "splat"

the elephant survives the first 38 hits then gores and tramples out intrepid research intern

(the elephant is relevantly unharmed, the inters was weak, it has a small bruise in its side)

the intern also survives after 22 surgeries, and an extended hospital stay

 

yes it is an extreme example

but dose this get the point across

big things are harder to kill, because they are big,

as in bigger then you are, as in if you attach them you go "splat"

 

also you know what i meant, dont be petty, we can compare the fitness of two species, not mathematically, but conceptually

Edited September 20, 2012 by akh

[Phi for All]

i can back this up with simple logic

 

we have 2 creatures

one is an amoeba small single celled tiny

the other is a elephant

 

we take a hammer and hit both with said hammer repeatedly

the amoeba survives the first 25 hits, but eventually goes "splat"

the elephant survives the first 38 hits then gores and tramples out intrepid research intern

(the elephant is relevantly unharmed, the inters was weak, it has a small bruise in its side)

the intern also survives after 22 surgeries, and an extended hospital stay

 

yes it is an extreme example

but dose this get the point across

big things are harder to kill, because they are big,

as in bigger then you are, as in if you attach them you go "splat"

 

also you know what i meant, dont be petty, we can compare the fitness of two species, not mathematically, but conceptually

Take your elephant to the edge of a 15' cliff, along with a mouse instead of an amoeba. They both scare each other and fall off the cliff. The mouse not only survives the fall but scampers off practically immediately. The elephant is broken and crippled, if not dead outright, because he is larger. And that's a more realistic natural occurrence than being beaten by a hammer.