Evolution to explain my existence

[kitkat]

It is apparently difficult for many of us to understand how evolution is actually defined. Please correct me if I am presenting the wrong assumption.

 

Evolution is descent with modification (Life can only come from life) and nature never has to start from scratch again right? Is this the correct interpretation in a nutshell? I realize that there is several factors involved in this process.

If true then the fact that I am here living right now, my ancestry goes back before I was classified as Human all the way back to the beginning of the first life on this planet. My line of descent would have many different names to describe who my ancestors were at any particular time frame in history. Humans evolved from many different lines of classification of humans, primates, and before that no one really knows due to lack of fossil evidence.

In other words the only way for me being alive today is because every generation in history lived long enough to produce the next generation that goes back to its origin.

[Sisyphus]

Well yes. You and I and everyone else are descended from a very, very long line of individuals who successfully produced offspring. Obviously. Similarly, the human species (and every other living species) is descended from a very long line of species who managed not to go extinct.

 

That's more just logical necessity than employing any principle of evolution.

[cypress]

Well yes. You and I and everyone else are descended from a very, very long line of individuals who successfully produced offspring. Obviously. Similarly, the human species (and every other living species) is descended from a very long line of species who managed not to go extinct.

 

That's more just logical necessity than employing any principle of evolution.

 

Is it logical necessity or presupposition? Is it not logically possible that some living species are descended from short lines of species? Is there some logical reason that cannot be some other way? It's not so much that I doubt there exist very long lines of offspring, it's just that we should try to be accurate lest we oversell our favored ideas.

[eclecticcowboy]

Is it logical necessity or presupposition? Is it not logically possible that some living species are descended from short lines of species? Is there some logical reason that cannot be some other way? It's not so much that I doubt there exist very long lines of offspring, it's just that we should try to be accurate lest we oversell our favored ideas.

[Ringer]

Is it not logically possible that some living species are descended from short lines of species?

What's short? The fact that most all living things have very similar genetic blueprints makes it far more possible that we all come from a very long line of ancestry. Not to say it isn't possible for there to have been multiple original organisms, but even it that's true it's still a long line of speciation.

[Sisyphus]

Is it logical necessity or presupposition? Is it not logically possible that some living species are descended from short lines of species? Is there some logical reason that cannot be some other way? It's not so much that I doubt there exist very long lines of offspring, it's just that we should try to be accurate lest we oversell our favored ideas.

 

The logical necessity I was referring to was that 100% of your direct ancestors managed to reproduce. As for the length of the line, it's not inarguable until you look at the empirical evidence.

[cypress]

The logical necessity I was referring to was that 100% of your direct ancestors managed to reproduce. As for the length of the line, it's not inarguable until you look at the empirical evidence.

 

Ah if that's all and if it is more logical necessity than evidence then the evidence must be weak also.

[eclecticcowboy]

Is it logical necessity or presupposition? Is it not logically possible that some living species are descended from short lines of species? Is there some logical reason that cannot be some other way? It's not so much that I doubt there exist very long lines of offspring, it's just that we should try to be accurate lest we oversell our favored ideas.

I tried to answer this once and I think I lost my post so will try to answer this again. As I understand your question you are asking if evolution can restart or in other words can organic molecules, i.e. amino acids, be formed by lightning strikes in the ocean say and start a new line of evolution. Well certainly anything that happened once can happen again. However, in the begining, when the first building blocks of life were formed they were free to float around as long as they wanted (to be anthropromorphic) and combine and grow or whatever at their leisure. Now, however, as soon as any proto life spontaineously formed some passing organism would see it as food and gobble it up. So although the probability of new lines of evolution are mathematically possible they are highly unlikely.

[cypress]

What's short? The fact that most all living things have very similar genetic blueprints makes it far more possible that we all come from a very long line of ancestry. Not to say it isn't possible for there to have been multiple original organisms, but even it that's true it's still a long line of speciation.

 

Fewer than 10 is definitely short in my opinion. What's long for that matter? Given the relative rarity of functional proteins as compared to the totality of sequences (less than 1 in 10^74) it makes perfect sense that we find an abundance of similarity throughout life. How do you figure mere similarity (often less than 50% sequence similarity) makes it far more possible that we came from a very long line than from a short line?

[insane_alien]

Ah if that's all and if it is more logical necessity than evidence then the evidence must be weak also.

 

i don't see why you think this.

 

if you're at the top of a tall building and cannot see down the sides, you can logically deduce that the building must have a bottom(as it is still standing).

 

the evidence is the stability of the building and the logical necessity is that it has a bottom.

 

in the case we are presented here the existence of each and every one of us is the evidence(quite solid evidence really) and the logical necessity is that, from the start of the chain all our ancestors successfully reproduced.

 

your parents reproduced successfully, your gandparents did too. and so on and so on until you get all the way back to the primordial soup the first cells appeared in.

 

its not particularly complex or intricate logic here.

[Sisyphus]

Ah if that's all and if it is more logical necessity than evidence then the evidence must be weak also.

 

What?

[cypress]

I tried to answer this once and I think I lost my post so will try to answer this again. As I understand your question you are asking if evolution can restart or in other words can organic molecules, i.e. amino acids, be formed by lightning strikes in the ocean say and start a new line of evolution. Well certainly anything that happened once can happen again. However, in the begining, when the first building blocks of life were formed they were free to float around as long as they wanted (to be anthropromorphic) and combine and grow or whatever at their leisure. Now, however, as soon as any proto life spontaineously formed some passing organism would see it as food and gobble it up. So although the probability of new lines of evolution are mathematically possible they are highly unlikely.

 

Interesting, but your conclusion is based on a presupposition about how life might have first started. Change that presupposition and your conclusion of likelihood can change dramatically. For example why assume just one kind of original life form? Why assume proto-life spontaneously forms?

 

i don't see why you think this.

 

if you're at the top of a tall building and cannot see down the sides, you can logically deduce that the building must have a bottom(as it is still standing).

 

the evidence is the stability of the building and the logical necessity is that it has a bottom.

 

Yes because we know some things about newtonian physics and buildings and this information allows us to eliminated alternatives. In the case of past relatedness we lack the information that would allow us to reduce the alternatives.

 

in the case we are presented here the existence of each and every one of us is the evidence(quite solid evidence really) and the logical necessity is that, from the start of the chain all our ancestors successfully reproduced.

 

your parents reproduced successfully, your gandparents did too. and so on and so on until you get all the way back to the primordial soup the first cells appeared in.

 

its not particularly complex or intricate logic here.

 

No not complex or intricate, but to suggest it is necessity is faulty logic. Just because we reproduce does not make it a necessity that all species are related. It might be so, but it might not be so.

[Moontanman]

Interesting, but your conclusion is based on a presupposition about how life might have first started. Change that presupposition and your conclusion of likelihood can change dramatically. For example why assume just one kind of original life form? Why assume proto-life spontaneously forms?

 

Because we have no logical alternative?

 

Yes because we know some things about newtonian physics and buildings and this information allows us to eliminated alternatives. In the case of past relatedness we lack the information that would allow us to reduce the alternatives.

 

 

What other alternatives also also allow what we see in nature to be true?

 

No not complex or intricate, but to suggest it is necessity is faulty logic. Just because we reproduce does not make it a necessity that all species are related. It might be so, but it might not be so.

 

Again I'll ask what other alternative is there? What evidence do you have for this alternative? Can you give any reason to suppose there is recent origin for any species? What species would that be and what is your evidence for this recent origin?

[Ringer]

Fewer than 10 is definitely short in my opinion. What's long for that matter?

And what evidence that there is any organism that has less than 10 generations that has been naturally formed. 

 

 Long is the billions of years of fossils that gives a large amount of evidence of speciation over long periods of time.  The reason we use this view of evolution is because it's the only viable explanation we have as to way things are the way they are.  If there is good conclusive evidence otherwise we would approach evolution from a different stand point, but there's not so we don't.

Edited August 1, 2010 by Ringer

[Sisyphus]

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Moderator Note

There are already several active threads about creationism. This thread was about a simple question that was answered. Please do not bring in OT debate and fringe claims in topics about mainstream science. I'm temporarily closing this thread, but kitkat, if you'd like it opened again, just private message me.