IluvTTATT said:
Species A reproduces and there is a species Aa and a species Ab. Species Aa is more suited to survive the change in environment and therefore ends up surviving... Perhaps species Ab also can survive but need to move to a different place where the conditions are more favorable to its survival. This is why there are multiple species with different evolutionary paths...
Well, members of the same species typically migrate to different areas to expand the range and to find new food sources, and they MAY diverge apart from the other group, due to different environmental conditions; it's the change in environment that leads the process, and those that survive pass on their genes. Of course, genetic mutations develop at a fairly constant rate (due to coding errors during mitosis, and radiation, etc), so it's not like the animal consciously decides to adapt as if to ANTICIPATE the need: that's not how evo works. If a mutation proves to be advantageous under those different conditions, then the members are more likely to survive.
Here's a short video on how ring species arise, posted by YouTuber Potholer 54:
http://www.youtube.com/watch?v=Pb6Z6NVmLt8
There's also a classic example of ring species seen in salamanders in CA:
http://evolution.berkeley.edu/evolibrary/article/devitt_01
(click on 'next' on that page to read the rest of the article.)
IluvTTATT said: The factors that make us human, have they evolved evolution itself? Have we somehow avoided or changed the nature of the game?
Oh, without a doubt.
We're the first species to understand evolution and our understanding of medicine has altered the results of 'natural selection', since eg someone who would die of a certain disease in childhood a century ago (eg due to measles/mumps/rubella) would not face that pressure, since we now have modern vaccines that prevent deaths from these killers. Point being, what used to be a selection pressure that affected the gene pool has largely been eliminated as a factor (at least in populations that have access to the vaccine, since death still occurs in 3rd World countries in 2013 in areas like Asia and Africa).
In fact, even the individual decisions of humans has a slight effect on evolution, eg those who make bad decisions aren't called candidates for "The Darwin Awards" for nothing! So those eg who die in the name of refusing blood are actually participating in their own 'natural selection' (although the odds of dying from refusal of blood transfusion are likely low-enough to make that factor a weak selection pressure). Same goes for those who refuse vaccines for their children, due to trusting a certain famous celebrity blondes who are stars of film and TV (weak pressure, at best, but still an example of selection at work).
IluvTTATT said: My other concern is with Intelligent Design. Something that seems designed does not necessarily mean that there was someone intelligent behind it. Case in point is snowflakes and crystal structures... No design there, it's just physical laws at work. However, a painting of a child, no matter how crude it is, clearly had a designer behind it.
Sure, but remember there's a fundamental difference between the rules governing carbon-based life and that of other atoms: just saying, the rules for living matter are governed by organic chemistry, and are COMPLETELY DIFFERENT from other inorganic (non-living) matter. Apparent design observed in living creatures is NOT equivalent to apparent design seen in say, a cave drawing: to assume otherwise is a false equivalency, since all prior examples of rock drawings have required someone to draw it.
IluvTTATT said: There are many complex structures in biology that just seem to me like they were designed; for example, the way that veins and arteries are placed in some animals to resemble a counter-current heat exchanger, instead of them being separate and losing body heat? What process in evolution explains apparent design?
Of course, the concept of counter-current heat exchange arose much later than when it was discovered in cold-weather animals, where it likely serves as a way to conserve energy required to maintain the organism's core body temperature; noting such similarities between designs and physiological function only was possible AFTER science discovered the dynamic existing in animals.
But why does it exist? Same reason as any other adaptation: it provides better survivability to organisms that have the trait in a certain environmental condition, and eventually the trait may become found throughout all members on the species by increasing the frequency of the trait in the gene pool such that the trait MAY become 'fixed' (unless some random mutation occurs: if it does, the progeny with the less-advantageous mutation may die off before reaching the age of reproduction, maybe even being aborted by it's mother or soon after birth if it mutates into a lethal disadvantageous trait).
Something to keep in mind is that some mutations get expressed rather late in life (i.e. AFTER the organism reaches the age of reproduction and manages to pass its genes to their offspring before they can harm the organism). These types of mutations are not susceptible to natural selection (or only weakly selected against), since the organism passes on it's genes BEFORE they can express in the parent so it can be selected against.
A great example of that situation is Huntington's chorea, a genetic disease that results from a mutation which can express in a late-onset form, hence the mutation avoids the 'culling effect' of natural selection, since it cannot act on traits BEFORE they are expressed:
http://evolution.berkeley.edu/evolibrary/article/medicine_05
IluvTTATT said: Please let me know what I should read to enlighten me. I want to know both sides of the argument, and I already know that one side was cheating and lying.
When I first learned about this stuff, I didn't think much about "sides", but was simply too fascinated in learning what IS known, since it was "no contest": the Bible doesn't offer anything like evolution, since "God Dun It!" is not an explanation of actual mechanisms, but simply a non-answer, a inquiry-stopper. The difference quickly becomes apparent once you start learning about how evo operates.
Adam
