Evolution Must Happen, it is logical

I do agree that gene pools undergo change, and that speciation can occur. In the sense of "continuing process of change" (dictionary.com/evolution), I will even agree that evolution occurs. However, I tentatively hold that such change results in a decrease of fitness in a group. Said decrease in fitness would make large evolutionary changes impossible, because a population would have died out before such a change could be made.Therein lies the error (that I see) in you logic: that populations can undergo large amounts of genetic change without going extinct.The only other proposed barrier between "Macro-evolution" and "Micro-evolution" that I know of is "Irreducible Complexity," but I am not quite sure the idea behind that argument is valid (the scaffolding rebbutal appears solid).TTFN,
JT(By the way, that is a well done OP.)

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However, I tentatively hold that such change results in a decrease of fitness in a group.

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In what way and why?

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Via the accumulation of harmful mutations, because natural selection cannot get rid of enough of them.For example, take humans. Nature magazine published an article stating that the rate of harmful mutations in homo sapiens is possibly more than 1.6 per generation. Natural selection can filter out egregously harmful mutations, but ones that are only slightly deleterious are more insiduous. If the difference between two organisms is a small number of mutations that have only a minute effect on fitness, natural selection will take much longer to eliminate them, if it even can. In fact, the article's abstract states that: "A large number of slightly deleterious mutations may therefore have become fixed in hominid lineages."The high rate of harmful mutations also led the authors to the conclusion that: "the effects of deleterious mutations may have combined synergistically." For mutations to combine synergistically (synergistic epistasis) means that each mutation has a more harmful effect than the one before it - two equally bad mutations would be more than twice as harmful as a single bad one. If harmful mutations did combine synergystically, then a small number of harmful mutations could make enough difference for natural selection to operate on. However, another Nature article states that:

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The theoretical findings have focused the attention of experimentalists on synergistic epistasis1, 10-16. However, there is no strong experimental support for the idea that synergistic epistasis is ubiquitous13, 16. This is surprising because, in the absence of synergistic epistasis, it is difficult to explain how species with relatively small local populations (for example, mammals and trees) can survive genetic drift3, 7. Populations with high genomic mutation rates ( U) are also difficult to explain without synergy, and there is evidence that high values of U may be common3, 17-21.
the article continues on and proposes a theoretical model for the possibility of synergistic epistasis in small populations. I will be happy to debate about it if anyone wishes.[]

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With the current evolutionary timeline and our understanding of genetics, it is surprising that many types of organisms are not extinct because of the gradual decrease of fitness caused by an accumulation of harmful mutations.JTP.S. I apologize for the lengthy delay -- I was busier with school than I thought I would be when I first replied to your post.

Thank you, that is a good point. But wait - whose side are you on? JT

I don't deal with "models," or "theories," or any other constructs put forward by ATHIEST, SCUMBAG evilutionists as "Science" (to hide from KNOWLEDGE)! I deal with TRUTH! Just kidding. Yeah, that's the side I think I'm on.

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JT

That is only true for the short term. After enough loci had recessive harmful mutations, the chances would be non-negligible that loci would be homogeneous-harmful, and additional harmful mutations would have an effect. Which is a problem — a population in a stable environment would develop a large, invisible burden. When — not if — the environment changed, the population would suddenly be forced to confront the massive load it had been carrying. This is the problem: it is likely that over time small populations will become extinct due to genetic load, so for prolonged survival, organisms need to exist in large populations. Large populations, however, are found where the environment is favorable and stable. But in such environments, organisms accumulate large genetic load, and are not equipped for environmental change, which inevitably comes.I also want to point out something the article says:

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The negative effect of permanent contamination of populations because of spontaneous mutations does not appear to be very high if judged from the relatively good health of humans or many wild and domesticated species.

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The fact that populations today generally have little genetic load (despite a proclivity to attain on) can also be attributed to life not having existed for a long period of time, and thus not having had sufficient opportunity to develop a large, deleterious genetic load. If 20 million years worth of mutations should see us in bad health, and we aren’t, maybe there haven’t been 20 million years worth of mutations Your post just made my day. It just doesn't get better than mutations in the heterozygous loci of Saccharomyces cerevisiae. Heady stuff, science.JTNote: 20 million years is a number I pulled out of the hat just because it sounds nice. It just means the really long time a bunch of populations have had to accumulate harmful mutations.