Speedwell
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- May 11, 2016
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A strange dichotomy, considering that processes using random variation and selection have a wide application in industrial design and manufacturing.And then the question boils down to: "Chance or design and manufacturing?"
And here we have some statements that reveal your complete ignorance of how the real theory of evolution is supposed to work.They just don't believe that procreated random mutations can write data for specialized organs.
It's never been observed either.
Obviously only the viable survive, but the changes are due to data corruption that don't get corrected.
Here is an answer I gave to a creationist who wanted me to explain how speciation occurs according to the real theory of evolution. He ignored it, of course, because it wasn't what he wanted to hear. Why don't you take a crack at it?
First, evolutionary biologists don't see speciation as a big deal. Species aren't pre-existing categories into which creatures evolve; they are descriptive, not prescriptive. When part of a population is subjected to different selection criteria than the rest, it will evolve to meet those new criteria. If it evolves enough that the two groups are no longer interfertile, a new species is said to have formed. But the process is slow and partial interfertility will last a long time. There is no "hard line" between species. That is why the determination of species is sometimes difficult and can be controversial.
How does it happen? No offspring is exactly the same as its parent. In each generation the population will present a range of variants to the environment for selection. For a given heritable trait, the length of a limb, say, the distribution of variation will be random (think "bell curve"). Most variation will be near the average, with outriders at either extreme, like a bell curve. If selection criteria are stable, the central group will survive to reproduce, the outriders not so much. However, if the selection criteria change, there will be already in the population at least a few individuals on the edges to take advantage of the situation. As they reproduce more successfully, generation by generation, than the individuals nearer the original central tendency and on the other side of it, the central tendency will shift in that direction, producing more outriders to take advantage of further shifts in selection criteria.
And so on. How long? Hard to say. It depends on the size and diversity of the gene pool and the degree of selection pressure. Maintaining the diversity of the gene pool is key to to successful evolution; a population of clones would generate little or no variation and would not be able to evolve. Gene pool diversity is also reduced by the normal action of natural selection. That's where mutations and other contributors of diversity come in.
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