Origins of Life

[Tina]

I am taking a biology class and we are currently learning about evolution. Apperantly, their theory is that RNA could be the source or that primitive cells that survive by taking energy from chemicals could be it.....or that a anaerobic prokaryote was invaded by an aerobic prokaryote but bonded to form a cell with mitocondria........but the teacher mentioned how studies have shown that the human race seemed to be traced back to a small group of people about 200,000 years ago since mitocondria are passed down from mothers to children.

Which makes me think about the flood and the small group of people on the ark.......

But I'm confused as to how there were Native Americans already in America when people from East traveled here....

Any thoughts?

[Reactionary]

But I'm confused as to how there were Native Americans already in America when people from East traveled here....

I think the Native Americans moved through Siberia, then crossed the Bering bridge (as the sea was probably frozen), and so came to America. Some settled in Alaska, while some continued to the south, all the way to South America. There are different theories about human migrations, but this seems most probable IMO.

[Stu]

One thing we must remember surrounding the origins of life debate is that prior to the existence of biota there is no natural selection. Nothing can be selected for. All we have are free roaming molecules.

Therefore all the processes and steps leading up to the "creation" of the first self-replicating organism must have occurred through nothing more than chance and chance alone.

[Proinsias]

The estimates for humans arriving in America are not very accurate. Something like between 10 and 50 thousand years ago. The theory goes that they probably went across the area around Siberia/Alaska

One thing that is generally agreed upon is that the most recent common female ancestor that we all share goes back before humanity made it to the Americas.

The current ideas as far as I'm aware, though I'm not very up to date it must be said, is that a relatively small population of anatomically modern humans suddenly increased rapidly in numbers and began moving out of Africa somewhere around 50-200 thousand years ago. This particular population, though perhaps not the only population of humans around in Africa at the time, is the one from which we can all claim ancestry.

[Proinsias]

One thing we must remember surrounding the origins of life debate is that prior to the existence of biota there is no natural selection. Nothing can be selected for. All we have are free roaming molecules.

The idea of chemical replicators being the precursor to biology still allows for selection. Not saying it is true but I'm not sure why biology is needed for natural selection. Replication within an environment is the theoretical basis for natural selection, biological life is not strict required in the theoretical sense.

[Tina]

Therefore all the processes and steps leading up to the "creation" of the first self-replicating organism must have occurred through nothing more than chance and chance alone.[/quote]

Our creation happening only by chance doesn't make sense. Just like if you put computer parts in a box and shook it up, the peices would't come together and make a working computer. It is designed. Just as everything else is.

[Stu]

The idea of chemical replicators being the precursor to biology still allows for selection. Not saying it is true but I'm not sure why biology is needed for natural selection. Replication within an environment is the theoretical basis for natural selection, biological life is not strict required in the theoretical sense.

Yeah you make a good point. However IMO that would only begin to apply at a particular point. Surely prior to that they are nothing more than the sum of their parts, molecules and macromolecules existing purely by chance; where "natural selection" is in fact nothing more than pure dumb luck.

Our creation happening only by chance doesn't make sense. Just like if you put computer parts in a box and shook it up, the peices would't come together and make a working computer. It is designed. Just as everything else is.

I agree, there is far more merit in Darwinism than than there is in the fantastical OoL stories doing the rounds. And of course one hinges on the other, can you say house of cards..

[zoegirl]

One thing we must remember surrounding the origins of life debate is that prior to the existence of biota there is no natural selection. Nothing can be selected for. All we have are free roaming molecules.

The idea of chemical replicators being the precursor to biology still allows for selection. Not saying it is true but I'm not sure why biology is needed for natural selection. Replication within an environment is the theoretical basis for natural selection, biological life is not strict required in the theoretical sense.

The idea behind chemical selection is that the chemicals that were able to, because of their make-up, chemistry, design, what have you, could replicate and thus keep going, verses molecules that don't replicate...well, that means that one molecule "survived" and replicated more than other molecules.

[sandy_mcd]

.but the teacher mentioned how studies have shown that the human race seemed to be traced back to a small group of people about 200,000 years ago since mitocondria are passed down from mothers to children.


But I'm confused as to how there were Native Americans already in America when people from East traveled here....

Where are you starting from? For example, do you believe in an old or young Earth? Acceptable answers to your question depend on what you presently believe.

The studies your teacher referred to deal with the last common ancestor of humans alive today. This does not mean that there were only a handful of people alive at that time.

[musician]

I find it difficult to believe that 'nature' would so conveniently organize itself into near-mutally-exclusive, universal life and death modes.

- Nathan

[Tina]

[/quote]Where are you starting from? For example, do you believe in an old or young Earth? Acceptable answers to your question depend on what you presently believe.

The studies your teacher referred to deal with the last common ancestor of humans alive today. This does not mean that there were only a handful of people alive at that time.[/quote]

I am really not sure which one I believe. I want to say young Earth since it might be that when God made it, He made it at a certain age (like Adam and Eve) but old Earth can make sense too. I'm undecided.

[sandy_mcd]

In that case, i would recommend Reactionary's (although perhaps land bridge for frozen water) and Proinsias' explanations.