Sticking a fork in Natural Selection (Introduction)

by xeno6696 , Sonoran Desert, Sunday, December 11, 2011, 16:57 (4709 days ago) @ David Turell

But I really don't understand what's wrong about the idea of a demand-based evolutionary system--the one we have.

I do agree with you that the environment produces demands on each organism to which it must respond if those demands are serious enough.

Normal reproduction results in a great deal of non-deleterious mutations. If the environment is stable over time, I understand that these changes will accumulate--but likely not manifest, because largely, mutations that don't result in death result in:

1. Dormant abilities that don't appear to have any immediate use.

2. Completely benign changes.

The changes don't manifest themselves until "Natural Selection," ie,

3. the organism gains a pure benefit.

4. The environment shifts (either through mobility, seasons, or something else like disaster...)

From my perspective, Natural Selection IS the prime motivator of change. IF an organism isn't required to change until its under stress,

Whoa: You or we need to define terms. Natural selection is by my definition is a process that comes into play as the organism is challenged by changes in its milieu. The motivator is the changing environment. NS is the result of the competition of the organism with the changes.

I'm looking at Natural Selection in a microscope: we have a whole organism and its population. A "Selection event" occurs and then the organisms respond. The key to my thinking (and why I've been stubbing my toes with you and dhw) is that I don't see how we can say Natural Selection isn't the driving force of evolution when we agree that:

1. We have a "demand-based" evolutionary system.

2. The cause of the demand are called "selection events."

3. A species (viewed as a group) changes in response to the selection events.

Lets say we're dealing with the horse example. When you look at the progression of horse fossils, lets think of each fossil as a snapshot. Hyrocotherum was clearly under selective pressure to become mesohippus--for a brief period of time.

If we agree that the system is demand-based, and we agree that selection events are the cause... it thus follows that natural selection is the primary cause of speciation. I don't see how it makes any difference that epigenetics or random mutation are functions that create the genetic variation when we have a pretty clear image of cause-and-effect in my mind.

Does this make my confusion a little more clear?

As an aside--I know no other place to put this--I'm starting to think that the distinctions we make between species is in many cases spurious... it seems to me that they are as arbitrary as the borders on a map.

I realize David and you both consider this a passive process, but it's only passive from a naive perspective... ie, the process of a new individual being created (sexually or asexually) is hardly what I would call passive. It's passive from an individual perspective--yet none of us would have a problem with the argument that after the act of intercourse, our kids came about by processes nearly completely uncontrolled from ourselves. (I don't see how the "passive" argument holds...)

This is apples and oranges. The act of reproduction is NOT any form of selection. Selection occurs AFTER reproduction produces a new organism in a hopefully new and capable form.

I can think of some corner cases around what you say here, but I think we're talking past each other here... you've said before that you don't see how a passive process could bring about a species. What I was attempting to argue here, is that most biological things we take for granted--are passive processes--they require no direct intervention from the organism itself.

--
\"Why is it, Master, that ascetics fight with ascetics?\"

\"It is, brahmin, because of attachment to views, adherence to views, fixation on views, addiction to views, obsession with views, holding firmly to views that ascetics fight with ascetics.\"