1. In the book it describes the orgin of life on earth by evolution. The evidence that the book offers for the orgin of life is that a variation exists within the genes of every population. It states that some species are better suited to survive because of the variation. It also states that follisls give proof that species evolved from species before.
             2. The evidence that the book offers of "spontanous orgin" is only a hypothesis, although it's been tested and confirmed. They state that many of the organic building blocks of life were made from molecuses of non-living matter.
             3. The book tells us about the Miller-Urey experiment, but there's nothing really to support their theory of evolution, so why do they put it in our book? It shouldn't really be considered a theory because they can't support it enough.
             4. "While scientists cannot disprove the hypothesis that life originated naturally and spontaneously, little is known about what actually happened" is a sort of mixed up statement. They can't disprove it, but yet little is known about what happened... so with that, how can they actually prove it to be a true statement? A slight bit of evidence might not be enough to prove it, even if they do think it is. That's like saying all dinosaurs were green, just from seeing one dinosaur they might believe that and claim it to be true.
             5. The book says that Endosymbiosis is how mitochondria originated through the evolution of symiotic, aerobic eubacteria. So knowing how mitochondria originated might help lead to the conclusion on how we originated.
             6. I think we're concerned with extinction because we want future generations to be able to see the animals. Also we might be concerned about extinction because if one animal becomes extinct others might become extinct also. For example, if the lions were to become extinct for some odd reason, other animal populations might grow incredibly and eat vegetation and other ...