Lack of evidence for a reducing atmosphere

HELEN

Most people who have had any passing introduction to evolution are familiar with the idea that the early atmosphere on the earth had what is called a ‘reducing’ atmosphere, or one lacking free oxygen. The reason this is presumed is primarily because for amino acids to form proteins, presumably spontaneously, could not be exposed to either free oxygen or water, as that would undo everything rather rapidly.

Therefore something called an oxygen-evolution curve had been formulated to show the gradual increase of oxygen in the atmosphere which was supposed to coincide with the development of life on earth which could cope with it.

Some of the earliest material tested for evidence of free oxygen has been dated at over two billion years old. And until recently, this material appeared to be confirming the idea that there was an early reducing atmosphere on earth. However, as the abstract of an article recently published shows, deeper drilling showed something else – that what they were testing was essentially the same as material found in places with abundant life.

Because some of the professional language may throw people off who are not used to it, I have taken the liberty to bold a couple of key points.

It looks like the oxygen-evolution curve may not be indicative of what really happened.

Keep in mind, please, that any of the creation models supposes oxygen in the atmosphere of earth from the beginning.

Tropical laterites, life on land, and the history of atmospheric oxygen in the Paleoproterozoic
Nicolas J. Beukes, Herman Dorland, and Jens Gutzmer, Munetomo
Nedachi, Hiroshi Ohmoto
Geology: Vol. 30, No. 6, pp. 491–494.

ABSTRACT: The ca. 2.2 Ga Hekpoort paleosol of the Transvaal
Supergroup in southern Africa has been considered a type example and the youngest iron-depleted paleosol formed under a reducing atmosphere in the early Precambrian. However, the mineralogical and
geochemical data on recently acquired deep drill core intersections indicate that the Hekpoort paleosol represents part of an ancient lateritic weathering profile with an iron-depleted pallid lower zone and an iron-enriched lateritic upper zone. Previous studies of the paleosol took place in areas where only the lower pallid zone was preserved from erosion prior to deposition of cover beds. The laterite profile is comparable to that of modern tropical laterites formed under an oxic atmosphere in the presence of abundant terrestrial biomass. Revised stratigraphic correlation indicates that the Hekpoort laterite profile is a correlative to highly ferruginous laterite profiles of Wolhaarkop in Griqualand West.
This information indicates that the oxygen-evolution curve, based on loss or retention of iron in paleosols, should be reexamined.

 

EARL DETRA

Helen, I'm not sure that you read this abstract correctly. I see nowhere that it says anything about the origin of life. According to my texts, this formation at 2.2 Ga, is very near the time when the oxygen curve is beginning its upsweep. What the authors may mean is that the curve needs to be set back a couple hundred million years, and not necessarily that it should be junked. In fact, I thought that the first living organisms are found in rocks of 3.5 Ga, so they occurred MUCH before this laterite deposit. That would mean that this article is irrelevant to the origin of life.

[ June 01, 2002, 10:35 AM: Message edited by: Administrator ]

 

HELEN

Earl, thank you for your post. I am wondering, though, why on earth the article would say the oxygen curve needs to be reexamined if the timing matches the current texts.

And although the article does not mention the origin of life, the further back things have to be pushed, the more evolutionists are going to run into a time problem on that subject. You see, what I have been told is that it took about a billion years for the first unicellular organism to become a multicellular organism. That is an AWFUL lot of generations! And you have to squeeze in incredible amounts of mutations with the time that is left to get life as we know it today! So I think the implications have to do with origins via the time problem.

 

THE GALATIAN

Helen comments:

It did. And most of the genes we carry were present by the end of
that
period. So most of the biochemical evolution of living things
occured in
that time. So it's not surpising it took a large proportion of the
time
living things have been on Earth.

The mutations have always been there, but unless there's some kind
of
dramatic change in environment, or an adaptive breakthrough like
fully
sclerotized exoskeletons, we don't see massive change.

http://www.pbs.org/wgbh/evolution/library/03/4/l_034_02.html

This, I think is the basis for the "Cambrian Explosion", as is the
rapid
diversification of mammals after the K-T boundary.

There's a lively debate going on about mammals even now. Some
answers are
already being found:

http://www.nceas.ucsb.edu/~alroy/Paleocene.html

 

EARL DETRA

Earl, thank you for your post. I am wondering, though, why on earth the article would say the oxygen curve needs to be reexamined if the timing matches the current texts.

Well, all of these curves are estimates, but the one I saw suggested that the curve rose rapidly starting at about 2Ga. So maybe that occurred somewhat earlier, say 2.3 Ga.

And although the article does not mention the origin of life, the further back things have to be pushed, the more evolutionists are going to run into a time problem on that subject. You see, what I have been told is that it took about a billion years for the first unicellular organism to become a multicellular organism. That is an AWFUL lot of generations! And you have to squeeze in incredible amounts of mutations with the time that is left to get life as we know it today! So I think the implications have to do with origins via the time problem.

I'm not too concerned because we still have over a billion years to work with from the first evidence of life to the oxidizing atmosphere. And now we've added 200 Ma to the time between higher oxygen levels and the first metazoans.

 

HELEN

Galatian, the concept that ‘most of the genes were present’ that we have by the time a unicellular organism evolved into a multicellular organism is based on the presumption of evolution. Can’t you folks see that almost every evidence you present is actually interpretation of data based on the presupposition that evolution is true? You cannot use a presupposition that is the same as the point you are trying to prove.

You are supposing that there was evolution from a unicellular to a multicellular organism, and then saying that because multicellular organisms all have a certain amount of DNA which appears to be the same, this proves evolution! A logical argument does not work that way. Your premise has to be different than your conclusion or all you are doing is going in circles where nothing – not data, not logic, not other logical interpretations – can break in.

The same goes for the rest of your post. Your arguments are entirely circular. But I challenge the presupposition that evolution happened in the first place, so therefore your ‘conclusions’ are not even applicable to the argument at this point.

Earl,
What do you think was the approximate generation time of the first unicellular organisms? The ones that were anaerobic according to evolutionary theory? E.coli has a generation time of about 20 minutes. Suppose we give the first organisms an hour, or three times as long? You are supposing over a billion years before the oxygen curve starts taking off, indicating a buildup of free oxygen in the atmosphere. I won’t ask you the mechanism by which anaerobic (metabolizing without the presence of free oxygen) became aerobic (requiring free oxygen to metabolize), because there is no good explanation and that would be a waste of time.

But for purposes of the argument, let’s assume it. In a billion years (rounding off), a single-celled anaerobic organism evolved into an aerobic multicellular organism with a differentiation in cells (in other words, not simply a colony).

And, on the average, it took about one hour for a new daughter cell to mature and divide into two more.

That is about 20 cell divisions a day, rounding down. That is about 7,300 cell divisions, or linear generations, in a year. In a billion years you have approximately, then, 7.3 x 10^12 generations before one cell became more than one cell as an organism. Here is an immediate problem: the minute your generation times increase you are out of time for evolution, even on a 4.5 billion year old earth! If you need that many generations just to get to multicellular from unicellular (mechanism not discussed here!), and then want to diversify from there, and as the organisms become more complex and need longer generation times, what is going to happen? Suppose generation time was a day? 7.3 x 10^12 days is how many years? We are already up into a number of years far exceeding the supposed 4.5 billion year age of the earth! Never mind that the generation time for a good many animals is a year or more! And with humans about 15 years minimum!

Now, if you back up that oxygen curve, are you claiming less time for the evolution of unicellular to multicellular, or are you claiming life evolved earlier than supposed currently?

 

JOHN PAUL

What is the evidence for a reducing atmosphere? I ask because as far as I am aware the only “evidence” the Earth at one time had a reducing atmosphere is that is the only condition from which self-replicating molecules, similar to the ones found in life, can form. Which when you get down to it, isn’t evidence at all.

So please can anyone present any evidence to support the concept of a reducing atmosphere here on earth. That way we can have a discussion about it.

 

EARL DETRA

What is the evidence for a reducing atmosphere? I ask because as far as I am aware the only “evidence” the Earth at one time had a reducing atmosphere is that is the only condition from which self-replicating molecules, similar to the ones found in life, can form. Which when you get down to it, isn’t evidence at all.

The argument is that banded iron formations can only have formed in a reducing atmosphere because of the relative insolubility of ferric iron. The iron had to go into solution as ferrous iron and then be deposited as a chemical sediment over large areas upon a variation in oxygen fugacity. So, no, your impression is wrong. Believe it or not, we are not trying to "prove" evolution any more.

There is evidence for a reducing atmosphere. There is also abundant evidence for reducing environments in existence today. For this reason, the whole argument seems rather moot to me.

So please can anyone present any evidence to support the concept of a reducing atmosphere here on earth. That way we can have a discussion about it.

If you wish, but I'm not sure that you can take this anywhere. Even if the atmosphere were oxidizing, there were some reducing environments in some locations at the time. Just as there are today.

* * * * *

[from a second email]

That is about 20 cell divisions a day, rounding down. That is about 7,300 cell divisions, or linear generations, in a year. In a billion years you have approximately, then, 7.3 x 10^12 generations before one cell became more than one cell as an organism. Here is an immediate problem: the minute your generation times increase you are out of time for evolution, even on a 4.5 billion year old earth! If you need that many generations just to get to multicellular from unicellular (mechanism not discussed here!), and then want to diversify from there, and as the organisms become more complex and need longer generation times, what is going to happen? Suppose generation time was a day? 7.3 x 10^12 days is how many years? We are already up into a number of years far exceeding the supposed 4.5 billion year age of the earth! Never mind that the generation time for a good many animals is a year or more! And with humans about 15 years minimum!

Now, if you back up that oxygen curve, are you claiming less time for the evolution of unicellular to multicellular, or are you claiming life evolved earlier than supposed currently?

Helen,
I remember no one saying what the rate of evolution is, or claiming that it remains constant. In fact, virtually all evolutionists are adamant that it is not constant. Also, just because we have a billion years to work with does not mean that it actually took that long.

To answer your question, I am saying that a billion years might have been enough for anaerobic organisms to adjust to an oxygenated atmosphere by evolving. In fact, if the Cambrian radiation is any indication, the actual transition probably occurred within a short part of that 1 billion years. Life may have occurred earlier than we currently know. All data we have is 'earliest known' data. In other words, we may in the future, find that life actually occurred somewhat earlier than we presently think. Also the earth may be somewhat older than we think, but is not likely to be younger.

 

THE GALATIAN

Galatian, the concept that ‘most of the genes were present’ that we have by the time a unicellular organism evolved into a multicellular organism is based on the presumption of evolution.

No, that's unnecessary. We merely note when in the geological column different kinds of organisms appear, and then examine the genes of organisms of those phyla living today. Without supposing evolution at all, we can show that most of the genes found in vertebrates appeared before multicellular organisms. One could, for example, suppose that God sequentially created each of them during the time the rock was being laid down, and that conclusion from the evidence would be the same.