Evolution: Science or Philosophy

[cheeseburger]

Will try to find it, it is from a book I read so I do not heve it handy.

The only source I accept is an article from an accredited scientific journal. Sorry. Books fall under many genres, one of which is fiction.

Not really, at least not in the sense I meant. Scientists have, at least theoretically, traced the mitchondrial DNA back to "Eve" through the testing the similarities of different women's mDNA and extrapolating it back to a woman in Africa.

Ok. Everyone knows that the Y chromosome is passed down along the male lineage, since boys are XY and only the father can contribute the Y.

Mitochondrial DNA is passed along the female lineage, because a fertilized egg cell, or zygote, already has a mitochondrion. When it divides, just like any other cell, the mitochondrion divides first, and then the cell divides. Sperm has no play in this, and so mitochondrial DNA is passed down from mother to child.

The reason I'm saying this is to give you a better understanding of why people even want to 'trace' mitochondrial DNA. However, tracing it 'all the way back' is pointless. Humans are not the only species with mitochondria, so if you want to find out where the organelle originates, you turn to the secondary endosymbiotic theory, which is a fancy way of saying "what you engulf and can't digest you make friends with."

The definition of a species I learned says that they are unable to mate.

This is an extremely simplistic definition that does not hold true in many cases. Mules are one common example.

The way things are done now, they sequence the genome of a species and compare it to that of another. Good match means either same species or pretty close - but keep in mind, the difference is in the .01% or there abouts. I'm no expert on this, but what you stated is clearly wrong.

Species are being redefined because of early misconceptions.

Reorganized is a better word.

Yet you cite a study that shows two different 'species' of butterflies mating to produce a third. To me that means that the definition has been diluted. Artificial support to force a hybrid that is not viable in nature does not prove evolution, it proves an outside influence.

Wasn't me. And by the way, this means nothing. Another example of this is D. Melanogaster mating with D. Yakuba. Big deal; they're unlikely to create viable offspring due to post-zygotic mating barriers. Nothing is being 'diluted,' whatever you mean by that.

My language was not clear, I am referring to the genisis of life on Earth. Every model I have encountered tells me that the chemiacals in the pre-biotic soup came together and formed the organic molecules that support life, and then life spopntaneoulsy arose. Am I mistaken in this? (By the way, i am aware that this a goss oversimplification, but my point is that the original event seems to be random.)

You are diluting it, but not entirely. Let me add some detail but still keep it really simplistic.

Basically, under the right conditions (reducing atmosphere, lightning, whatever) you form organic (organic simply means containing carbon) molecules that are polar on one side and non-polar on the other side. In an aqueous solution, the non-polar sides get pushed together and you get a very rudimentary membrane, allowing some separation. This means you can do things inside your membrane that couldn't go on outside. Once you have something that reproduces itself, like some self replicating RNA enzymes ('ribozymes') the cat's out of the bag and whatever replicates the fastest sticks around.

Adaptation to environment? I would have no idea, i am at a loss to explain how we went from asexual reproduction to binary reproduction anyway, another thing that has never been explained in any way other than, it happened, so it must have happened.

If you're at a loss, let me explain. Something that reproduces asexually can very quickly 'fill up' a niche that it is well suited to. Any change in that niche that makes it unfavorable for one of these creatures makes it unfavorable for all of the creatures since they're basically clones, and they all die.

And clearly environments change over time. Life is basically adapted to survive stressors. So, some mechanism that enhances variation among a species was highly selected for - since everything else died out once the environment changed.

Or, some creature multiplied so fast mutations became significant and added to the variation. Viruses and bacteria are like this; mutations add a lot of variation to a culture of bacteria because they reproduce something like once every couple hours.

Although bacteria can also reproduce sexually, at a greater cost. If you stress them, by say adding antibiotics, then the 'cost' of reproducing sexually outweighs the 'cost' of dying to the antibiotics, and they all suddenly start reproducing sexually and passinga round resistance genes.

I typed this a little rushed so I apologize for any spelling/nonsense errors.