Life

[Moontanman]

oes life occure any time a planet forms? At some point the condiditions are almost bound to right for life at least for a short time. Is life simply a chemical reaction that occures Naturally on any bvody that has teh right conditions, possibley (absolutly no proof of this) life might help the colescence of planetoids into plantets. Eventually life would become extinct due to changing condiditions,Earth just happened to be lucky enough that life survived.

[Racoon]

Thats a good question.

 

I would think life begins to occur after the planet has already formed itself for the most part.

One might surmise that life as we know it would have a rough go of it during planet formation; with all that violent, precarious activity and what not...

 

Astronomers Watch as New Earth-Like Planet Forms - Newser

[freeztar]

oes life occure any time a planet forms?

 

No, not to any existing knowledge.

 

At some point the condiditions are almost bound to right for life at least for a short time.

 

Can you explain what you mean by this.

 

Is life simply a chemical reaction that occures Naturally on any bvody that has teh right conditions

 

No one knows for sure, but that's probably the most likely possibility.

 

possibley (absolutly no proof of this) life might help the colescence of planetoids into plantets.

 

How would life help planets coalesce?

 

Eventually life would become extinct due to changing condiditions,Earth just happened to be lucky enough that life survived.

 

I suppose it could be possible, but I find it intuitively incorrect.

 

You might be interested in these wiki pages moontanman:

 

Astrobiology - Wikipedia, the free encyclopedia

Panspermia - Wikipedia, the free encyclopedia

[modest]

If we find microscopic fossilized life on mars (some people think we already have via ALH84001) then there will be a good case for the genesis of life anywhere liquid water is available. This is one reason I think a human voyage to mars is important. Indeed - what could be more important (biologically) than understanding the genesis of life?

 

-modest

[HydrogenBond]

The formation of life may be easier and more frequent than we think. The assumption that the formation of life is remote and rare, could be an artifact of the existing theory not up to the task.

 

Part of the reason I say life can form easier than we think, is based on an observation. If you look at evolution, life on earth has been evolving to where we have humans. But along side of this are still very simple single cell life forms. The question that came to mind, are these simple life forms out of the evolutionary loop, since it took billions years to go nowhere? Or did their precursors form, later, after the original batch of life?

[freeztar]

The formation of life may be easier and more frequent than we think. The assumption that the formation of life is remote and rare, could be an artifact of the existing theory not up to the task.

 

Part of the reason I say life can form easier than we think, is based on an observation. If you look at evolution, life on earth has been evolving to where we have humans. But along side of this are still very simple single cell life forms. The question that came to mind, are these simple life forms out of the evolutionary loop, since it took billions years to go nowhere? Or did their precursors form, later, after the original batch of life?

 

Just because they're "simple" does not mean they don't evolve, or are "out of the evolutionary loop".

 

I recommend this article as it is very illuminating. A bunch of what makes us are these "simple" "organisms". :naughty:

 

Annals of Science: Darwin’s Surprise: Reporting & Essays: The New Yorker

[Rade]

It depends on how we define "life". From our earth experience, life can be defined as 'self generated action mediated by nucleic acids'. Now, as far as we know, everything in the universe has potential for motion (action), but there is no evidence of nucleic acids being widespread (perhaps because we can not yet measure them at vast distances).

 

So, imo, to have life on other planets, motion of entities must be linked with nucleic acids because these chemicals allow for the information of motion to be replicated over time. If I was looking for life on other planets I would look for precursor atoms and molecules required to form nucleic acids. Of course it is possible that life on other planets uses some molecules other than nucleic acids to reproduce.

[HydrogenBond]

The real progress in evolution went into multicellular. These simple single cells should have had many random mutations over a billion years. Each would have selective advantage for further evolution. So why did they abort the mutations and stay stuck at step two? One only has to look at how fast disease is able to change and then compare that to no change in a billion years. Either nature can skip evolution or else it can begin anytime.

[modest]

The real progress in evolution went into multicellular. These simple single cells should have had many random mutations over a billion years. Each would have selective advantage for further evolution. So why did they abort the mutations and stay stuck at step two? One only has to look at how fast disease is able to change and then compare that to no change in a billion years. Either nature can skip evolution or else it can begin anytime.

 

Step 2? What got stuck at what step? When did evolution stop? Are you saying there should be more types of bacteria and single celled organisms today? Or, that all bacteria should have evolved into multicellular life by now? Can you please elaborate - I would like to understand.

 

-modest

[HydrogenBond]

What I am saying is simple single cell life either got stuck in evolution or formed after the original formation. It may be right on schedule if one assumes a more abbreviated evolutionary schedule. Those little guys make new cells all the time. Calculate the mutations for 1 billions years. How do they avoid this impulse for major change and stay simple?

 

All I am doing is using Darwinism and selective advantage. What is the advantage of staying close to the beginning of evolution? If there is an advantage to not evolving very far, selective advantage can also mean very slow evolution or no evolution at all.

 

One possible way to explain it, is evolution is a group event. In other words, there is always a bell curve of evolution with the sideline critters of the curve offering logistical support for life forms closer to the top of the curve. The simple stuff stays stuck so it can continue to offer logistical support for the money area of the evolutionary curve.

[modest]

What I am saying is simple single cell life either got stuck in evolution or formed after the original formation. It may be right on schedule if one assumes a more abbreviated evolutionary schedule. Those little guys make new cells all the time. Calculate the mutations for 1 billions years. How do they avoid this impulse for major change and stay simple?

 

All I am doing is using Darwinism and selective advantage. What is the advantage of staying close to the beginning of evolution? If there is an advantage to not evolving very far, selective advantage can also mean very slow evolution or no evolution at all.

 

One possible way to explain it, is evolution is a group event. In other words, there is always a bell curve of evolution with the sideline critters of the curve offering logistical support for life forms closer to the top of the curve. The simple stuff stays stuck so it can continue to offer logistical support for the money area of the evolutionary curve.

 

I see what you're saying.

 

I think the answer you're looking for is sex... er.. sexual reproduction.

 

For the first 2 or 3 billion years or so life got along developing quite slowly. It's a very long time for nothing much to happen - and indeed nothing much was happening as mother earth had not yet invented sex.

 

Single celled organisms reproduced via mitosis which means the cell splits into two exact copies of itself like Kirk on Star trek. This apparently isn't the most efficient way for evolution to advance life. Diversity isn't a quickly developing asset when everything is cloning itself. The circumstantial evidence of this is the 2 to 3 billion years of slow evolution.

 

Then God (or shall I say evolution) saw fit to endow these pathetic little lifeforms with a truly marvelous gift. Meiosis. Without getting into all the sticky details - let's just say its a new spin on reproduction. This happened some 1.2 to 2 billion years ago.

 

Shortly after the greatest invention of all biological history on earth - evolution took off. We soon had animals, plants, fungus, etc - all who evolved from one group of particularly randy little archaea that decided to be the progenitor of the entire eukaryote family.

 

Indeed, bacteria (and their like) that seem to be stuck in the evolutionary mud are mostly the lifeforms that evolved separate from those of us that have that key ingredient we love so much. Don't feel bad for them. All life was that way for at least 2 billion years. Besides....

 

Have you considered what we gave up for that key ingredient? Bacteria never die. They just divide. The stuff that's growing in your sink has been alive in one form or another since the genesis of life. We... well, we traded in immortality for a short life spent chasing Nikki around the dorms when I knew she was never gonna leave her boyfriend for me. I just loved the way she wore those cute little clips in her hair. I wonder what she's up to these days.

 

What was I talking about?

 

-modest

[raghu]

Have you considered what we gave up for that key ingredient? Bacteria never die. They just divide. The stuff that's growing in your sink has been alive in one form or another since the genesis of life. We... well, we traded in immortality for a short life spent chasing Nikki around the dorms when I knew she was never gonna leave her boyfriend for me. I just loved the way she wore those cute little clips in her hair. I wonder what she's up to these days.

 

What was I talking about?

 

:hihi: I think the last para explains the paradox posed by H-bond.

 

One can't really term multi-cellularity as evolutionary more advanced, & never

as evolutionarily more advantageous.

 

There are advantages, as well as disadvantages of multi-cellularity; one of which Modest has talked about, & many others, which are discussed in the paper given below.

So, there's sort of a trade-of between the two, at certain conditions, unicellularity might prove to be more advantageous than multi-cellularity, & at others, vice-versa!

 

An excellent example of this trade off is the dictyostelids:

a group of cellular slime moulds

 

 

 

When food (normally bacteria) is readily available they take the form of individual amoebae, which feed and divide normally. However, when the food supply is exhausted, they aggregate to form a multicellular assembly, called a pseudoplasmodium or slug (not to be confused with the gastropod mollusc called a slug). The slug has a definite anterior and posterior, responds to light and temperature gradients, and has the ability to migrate. Under the correct circumstances the slug matures forming a fruiting body with a stalk supporting one or more balls of spores. These spores are inactive cells protected by resistant cell walls, and become new amoebae once food is available. -From Wiki

 

http://dictybase.org/tutorial/about_dictyostelium.htm

 

Dictyostelium amoebae grow as separate, independent cells but interact to form multicellular structures when challenged by adverse conditions such as starvation. Up to 100,000 cells signal each other by releasing the chemoattractant cAMP and aggregate together by chemotaxis to form a mound that is surrounded by an extracellular matrix. -From: dictybase

 

However, I'd like to point to a recent paper by Martin Willensdorfer, freely available at:

 

[0801.2610v1] On the evolution of differentiated multicellularity

 

On the evolution of differentiated multicellularity

 

Author: Martin Willensdorfer

(Submitted on 17 Jan 2008)

 

Abstract: Most conspicuous organisms are multicellular and most multicellular organisms develop somatic cells to perform specific, non-reproductive tasks. The ubiquity of this division of labor suggests that it is highly advantageous. In this paper, I present a model to study the evolution of specialized cells. The model allows for unicellular and multicellular organisms that may contain somatic (terminally differentiated) cells. Cells contribute additively to a quantitative trait. The fitness of the organism depends on this quantitative trait (via a benefit function), the size of the organism, and the number of somatic cells. This model allows one to determine when somatic cells are advantageous and to calculate the optimum number (or fraction) of reproductive cells. I show that the fraction of reproductive cells is always surprisingly high. If somatic cells are very small they can outnumber reproductive cells but their biomass is still less than the biomass of reproductive cells. Only for convex benefit functions can the biomass of somatic cell exceed the biomass of reproductive cells...

 

This paper talks about the trade-offs of multi-cellularity, in comparison with freelancer unicellular micro-organisms.

It discusses conditions where the multi-cellularity would confer an advantage to the organism, & those, where the unicellulars would have an edge over the multi-cellular organisms.

 

Hope that the paradox is resolved for now! :hihi:

[coldcreation]

...

Then God (or shall I say evolution) saw fit to endow these pathetic little lifeforms with a truly marvelous gift...

 

Are you saying that god and evolution are interchangable? Let's put it this way: I don't understand your use of "god" in a discussion about biological evolution. It's almost like discussing evolution in a theology forum.

 

Or, are you just being provocative?

 

What gives...

[modest]

Are you saying that god and evolution are interchangable? Let's put it this way: I don't understand your use of "god" in a discussion about biological evolution. It's almost like discussing evolution in a theology forum.

 

Or, are you just being provocative?

 

What gives...

 

That's rich CC.

 

You'll notice my entire reply above is layer upon layer of innuendo and double meaning. I wrote it that way intentionally. When I say Meiosis is the greatest gift ever given by god... or some such... well... I'm sure you understand what I mean.

 

I may not believe in god, but if Natalie Portman showed up at my door right now, I'd thank him till the day I die.

 

-modest

[modest]

I don't understand your use of "god" in a discussion about biological evolution. It's almost like discussing evolution in a theology forum.

 

Or, are you just being provocative?

 

Off topic here, but I went on about this in applicability of deistic analogy and allegory

 

-modest

[Moontanman]

One more possible life bearing moon!

 

Could There Be Life On Saturn's Moon Enceladus?

[Thunderbird]

What I am saying is simple single cell life either got stuck in evolution or formed after the original formation. It may be right on schedule if one assumes a more abbreviated evolutionary schedule. Those little guys make new cells all the time. Calculate the mutations for 1 billions years. How do they avoid this impulse for major change and stay simple?

 

All I am doing is using Darwinism and selective advantage. What is the advantage of staying close to the beginning of evolution? If there is an advantage to not evolving very far, selective advantage can also mean very slow evolution or no evolution at all.

 

One possible way to explain it, is evolution is a group event. In other words, there is always a bell curve of evolution with the sideline critters of the curve offering logistical support for life forms closer to the top of the curve. The simple stuff stays stuck so it can continue to offer logistical support for the money area of the evolutionary curve.

 

The boundary is one of functions. simple single cell inhabit a simple fitness space, or environments therefore stay simple. Cells that inhabit the complex fitness space, of the internal environment of an animal have adapted to a more complex symbioses. The environments are hierarchal and serve as structural foundations, and functional supports.