Evolution Issues

[sergeidave]

Hi guys,

 

I will be totally honest here. I love science and I sincerely wish to understand it. Actually, everything is great and pleasant, math, physics, chemistry, etc. Tons of rational and logical concepts, everything makes sense (well, at least much of it, unless you are an Einstein or some other rare and luminous brain to understand it all).

But then I bump into Evolution and a world of mistery and unclearness unveils. So I would like to post some questions on some of those issues that "keep me awake at night" (ok, not really, but you know what I mean).

 

First of all, I'm still to find a believable/logical explanation about the abiogenesis issue, that is, life coming into existence by a superb-against-all-odds stroke of luck. Anyway, I've heard so many times that Evolution does not have anything to do with origins of life that, ok, let's not go there (let's pretend that we have no idea that there's this big "elefant in the room").

 

Let's say the issue mentioned in the last paragraph is solved and we now have the first "bit of living stuff" (the very first living cell, or whatever it was). This means we are now in "Evolution territory", I assume.

So, life is here and already a ton of questions arise from this "little" fact.

For example:

1.- Due to the amazingly high odds that the first bit of living matter had to beat to come into existence, was there just one lonely living cell or, as the "primordial soup" phrase suggests, did many living cells come into existence all at once?

 

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it .

 

Ok, I had planned to make a big post but my brake time is up. But it would be great to hear some thoughts about this. There's obviously more of these controversial points of discussion but this should be an interesting starting point.

I really don't know much about the subject so it's natural that I sound skeptic. I would really like to know if science have explanations or answers to this issues.

 

Thanks!

[Mokele]

1.- Due to the amazingly high odds that the first bit of living matter had to beat to come into existence, was there just one lonely living cell or, as the "primordial soup" phrase suggests, did many living cells come into existence all at once?

 

The whole "odds" thing takes on a new perspective when you consider just how big the oceans are and how long it took. Sure, life is improbable, but it took over 1.5 billion years to show up at all. Think of the probability that any set of grains of sand will form a particular geometry, but then consider the size of the beach. No matter how unusual the geometry, odds are it's there somewhere.

 

Anyhow, as far as multiple origins, this has been suggested (we can't know without fossilized microbes, a very, very rare find, and even those aren't informative about biochemistry), and the idea is that the common ancestor of modern life either survived extinction more effectively, or actively devoured the others.

 

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

 

That's basically it - anything that didn't reproduce would have died without offspring. Life may have originated many times, only to die off again. Our ancestor is merely the one that "got it right".

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it

 

Pretty much.

 

It's like the idea that if you have infinite monkeys with typewriters and infinite time, eventually they'll write Hamlet. Set the bar lower (say, write 20 pages of text), but give several quadrillion monkeys over a billion years, and you'll see lots of results.

 

It's also important to note that reactions aren't random - certain atoms and molecules preferentially stick together, and we can replicate abiogenetic development of important biochemicals like Cytosine and Uracil in the lab, in much shorter time with much smaller volumes.

 

Remember, modern oceans don't have many life-precursor molecules because living things quickly find and eat those molecules, but in the past, the whole ocean would have been a veritable soup of the precursors of life.

[Mr Skeptic]

1.- Due to the amazingly high odds that the first bit of living matter had to beat to come into existence, was there just one lonely living cell or, as the "primordial soup" phrase suggests, did many living cells come into existence all at once?

 

Well, the origins of life is still unknown and rife with speculation. In general, I think that what the primordial soup was, was a bunch of stuff halfway between alive and non-alive. Remember that there is not a sharp dividing line between alive and not alive (and then there is dead too). If you disagree with this, feel free to watch a cell die and tell me the exact moment when it is no longer alive.

 

Anyhow, it is likely that there was a lot of different life-like stuff in the primordial soup. Possibly all variants of a first one that can reproduce. Then eventually one gets all the stuff in a standard cell -- a distinct inside and outside, metabolism, replication -- and then eats all its competition.

 

But abiogenesis is rife with speculation and a different beast than evolution in the first place. Darwin simply said that god created the first cell, and then explained from there how everything else came to be.

 

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

 

No, cells aren't smart enough to "plan" anything but the most basic things and certainly not able to understand the concept of extinction. Despite this, they manage to reproduce quite prolifically.

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it .

 

No, the ability to reproduce is part of most definitions of life. I suppose it might be possible if you have a really loose definition of life.

[Kyrisch]

There are roughly a billion billion planets in the universe. Even if the odds against an event like abiogenesis is a billion billion to one against, chances are it happened once. Since we're here, it's only logical to accept that our planet was the lucky one.

[CharonY]

Or another way to illustrate odds. Assume you draw 100 cards from a deck of cards (and put it back and reshuffle after each draw). The chances to get that precise order you end up with is 1/(52^100). Yet you just did it.

[Daecon]

Or the odds of both your parents being born in the same century, and meeting each other, and having you...

[SkepticLance]

Some facts to help understanding.

 

1. The Miller experiment. Now repeated many times with many variations.

If you take a mixture of gases similar to what we believe the original atmosphere of Earth to be like, and pass strong energy through it, such as we would expect from lightning, ultraviolet, or meteor impact, then a wide range of organic molecules are formed, such as amino acids, purines etc.

 

Deduction suggests that early rain will carry these molecules into puddles or lakes or the sea. Over millions of years, the concentration will build up into the 'primordial soup.'

 

2. Certain minerals, such as calcite and the clay montmorillonite, cause some of these organic molecules to adhere, and line up. They they chemically link to form polymers.

 

3. Other organic molecules spontaneously form into sphere shaped 'vesicles', with a monomolecular membrane. In the presense of more raw material, these 'vesicles' will grow and split to form more vesicles. This is done by purely chemical processes. No biology involved.

 

Thus, we can deduce that the early Earth, from purely chemical processes formed a large mass of organic molecules, including a wide range of polymers, which would have been trapped within vesicles (like cell membranes) purely by chemical processes.

 

From this point, we need to envisage a polymer able to self replicate (as RNA does) inside a self replicating vesicle. This is the first ultra-simple living cell. As it continues its existence, down millions of generations, there will be changes to the molecule's structure. These variations leave many to die out and become extinct, while others will thrive and become the dominant forms. Evolution is under way!

 

The Earth appears to have been uninhabitable from its origin 4.5 billion years ago to about 4 billion years ago, due to a massive bombardment by asteroids, meteors etc. However, there are traces of hydrocarbons in certain rocks in Canada that have isotope ratios typical of living things, dated (though this is controversial) to 3.8 billion years ago. If this is true, then life came into being during a 200 million year window.

[iNow]

Some useful videos.

 

 

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-h9XntsSEro

[Kyrisch]

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it

 

This is a bit of a non-issue. You see, the term abiogenesis refers to the formation of the first self-replicating structure. We defined the event as the formation of the first structure that was able to "leave offspring" (mind you, at this point it was merely a ribo-nucleic or proto-nucleic acid that would spontaneously replicate through base-pair matching or some analogous process, as demonstrated in the videos iNow posted above). As such, your personification is a sort of false analogy -- it never had to "figure it out".

[lucaspa]

So, life is here and already a ton of questions arise from this "little" fact.

 

All your questions relate to abiogenesis, not evolution.

 

The one way we know will generate life from non-living chemicals solves all your "problems".

http://www.theharbinger.org/articles/rel_sci/fox.html

http://www.siu.edu/~protocell/

 

If amino acids are heated -- either dry heated in an evaporating tidal pool or at underwater hydrothermal vents -- they polymerize to proteins. When water comes back into the tidal pool or the proteins are carried into cooler water, the proteins spontaneously form living cells (called protocells), each about the size of a bacterium.

 

1. You get tens of thousands to millions of protocells each time the reaction happens. That solves your problem of how many.

 

2. The protocells grow and reproduce. It's not a "plan" but chemistry. However, that solves your problem of death.

 

3. Protocells probably formed millions of different times. In fact, they are still forming now at hydrothermal vents. Of course, the protocells formed now are facing living organisms with 3.8 billion years of evolution behind them. So the modern organisms have the protocells for lunch. But this solves your problem of whether it was a one-time thing or many times. It also means that the protocells competed against each other for many millions of years and evolved until all the cells around were descended from just one of them -- the last common ancestor.

Edited April 16, 2009 by Klaynos
fixed quote tag

[Glider]

Hi guys,

 

I will be totally honest here.

This is never a good way to begin a statement. It suggests that what follows is an exception.

[sergeidave]

Thank you for all your comments, guys! Pretty interesting stuff!

 

This is never a good way to begin a statement. It suggests that what follows is an exception.

 

C'mon man, at least provide some input to the matter being discussed, don't just criticize the way I express myself.

[forufes]

Set the bar lower (say, write 20 pages of text), but give several quadrillion monkeys over a billion years, and you'll see lots of results.

 

what if it's infinite pages of defined text..

infinite monkeys..

infinite time..

then what?

 

does the possibility still exists?

 

because you see, the certain conditions and terms needed to be fulfilled are the pages of text, and we keep learning more and more of them every day..we've never grasped them all..

no?

[foodchain]

1.- Due to the amazingly high odds that the first bit of living matter had to beat to come into existence, was there just one lonely living cell or, as the "primordial soup" phrase suggests, did many living cells come into existence all at once?

 

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it .

 

For number one I don't know when you call a cell living. If you mean did the first cells all come about during the same time, probably.

 

I think the answer to question two lies more in the physical sciences then just the life sciences. The process or processes that lead to life were abiotic, so my guess is thats why we have autotrophs.

 

For question three I think question two and one both apply. What ever physio-chemical process that lead to life is probably what was required, as for mutation is the process that natrual selection operates on. Not saying that life was guarenteed in that last statement, just thats how life exists right now as per the definition of life in this topic.

[dttom]

1.- Due to the amazingly high odds that the first bit of living matter had to beat to come into existence, was there just one lonely living cell or, as the "primordial soup" phrase suggests, did many living cells come into existence all at once?

 

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it .

Thanks!

 

There is a major problem in all your questions (at least personally I think there is), it is that you assume the most primitive 'living matter' as some sort of early cell, and you are confused with issues of leaving offspring. It is a significant issue to define the word 'life', if you define the word by 'cell', then I should say that 'cell' must have evolved to leave offspring. Becasue the origin of life should not be a cellular entity. A cell is far too complex to be the earliest 'living matter' (origin of life), natural selection could work only when certain replication mechanism was found, or evolved. This is the basic requirement for natural selection to occur, so that 'living matter' should be a replicator (being able to leave offspring) per se.

[forufes]

This is never a good way to begin a statement. It suggests that what follows is an exception.

 

nope, for me it says that his act of questioning evolution is not to be thought of as dishonest as are most queries questioning evolution. he's just trying to be cautious towards a "sensitive" subject.

[Edtharan]

First of all, I'm still to find a believable/logical explanation about the abiogenesis issue, that is, life coming into existence by a superb-against-all-odds stroke of luck

Ok, this is your first problem. You are phrasing that the origin of life is an against-all-odds event. This, according to current knowledge of the origins of life, is wrong.

 

It was not a chance event, but a product of chemistry.

 

The current best theory that I have heard (yes, it is not that we don't know how life got started, it is that we don't know which of the many that have been proposed was how it got started here on Earth) is:

- Basic chemical reactions with the chemicals that would have existed on the early Earth caused lipids to form (lipids are very easy to form).

 

- Because one end if a lipid molecule is attracted to water and the other is attracted to oily molecules (and that end is also oily), the lipids form a bi-layer where the oily ends line up with each other and the water attracted ends are turned outwards.

 

- Because the edges of this bi-layer are attracted to themselves the whole thing easily forms into a globule (or vesicle). You can see this yourself with soap bubbles as soap is a lipid)

 

- These early lipid bi-layers were quite permeable to small molecules and would allow them to pass through it. But it is fairly impermeable to larger molecules so if some of these smaller molecules could polymerise, then they would get stuck inside the vesicles.

 

- If these polymers could cause more of themselves to polymerise more easily, then any vesicle that had some would more rapidly accumulate them.

 

- These lipid bi-layer vesicles is that they can be broken apart fairly easily by collisions with objects like rocks and such, but they rapidly close up again. So if they were broken apart, any molecules in them would still remain then them but split between the two vesicles.

 

- Another thing about these vesicles is that if two come into contact, then one will take the lipids from the other causing it to shrink and even rupture (and you can do this with soap bubbles too).

 

- The ability of the vesicles to do this relates to certain pressures in them. If the polymers that lie within the vesicles can increase these pressures, then any vesicle that has them will have an advantage and it will destroy any vesicle that does not have them.

 

- Over time any refinement that helped the vesicle to survive amid a mass of other vesicles will give that vesicle an advantage.

 

It is not that the vesicles are trying to survive, it is just that the vesicles that do survive are the ones that are good at surviving.

 

1.- Due to the amazingly high odds that the first bit of living matter had to beat to come into existence, was there just one lonely living cell or, as the "primordial soup" phrase suggests, did many living cells come into existence all at once?

Any cells that reproduce (or reproduce quicker) have an advantage over the ones that don't.

 

To give you an idea of how powerful reproduction is, try this thought experiment:

 

If you have a single cell and every hour it splits off a new cell (and each daughter cell does the same), how many cells do you have after 1 day (or after 1 year )?

 

So even if there was only just 1 cell, there would be (very soon) millions, billion or even trillions of cells.

 

2.- Since all living beings die, did those first living cells "have" a plan to preserve life once their time to die came? I mean, even asexual reproduction had to be "figured out" before "anyone" could "make use" of it. Did those first bits of living matter have enough lifespan or longevity to "figure it out"? If not they must've died without leaving any offspring, so...

As I said earlier, the cells did not need to have a plan to survive, it is just that if they didn't survive, then ones that did survive are the ones we see today. The ones that reproduced outnumbered the ones that didn't and the ones that were better at defending themselves or eliminating the others did better and had more offspring.

 

3.- Does this mean that life managed to beat the odds not just once but many times to come into existence until it finally figured out how to leave offspring?? This one is tough, even just to think about it .

The vesicles that I talked about earlier probably would not be considered as being alive. However, they did have the ability for reproduction, even if it was assisted by outside factors (and any that could self reproduce would have a massive advantage over those that couldn't).

 

So even before life even got started reproduction was going on and as what we call living organisms came from such self reproducing chemical reactions, then by the time life got started, it was already equipped to reproduce.