Happy Wonderer

I'm not following you here. On the surface the question seems easy to answer: if an allele's frequency remains constant within a population than it seems to me that it is neutral wrt. reproductive fitness. If the frequency increases, then it is benefical. If it decreases it is harmful.

Of course the real world is a bit more complicated (harmful mutations may remain at a constant low rate, alleles are be linked to others, etc.) But that speaks to the difficulty of figuring out whether traits are neutral, not the logical impossibility of it.

HW

Principia

I agree with the sentiment. One can almost say that Keith has no purpose in this thread. He has gone in the span of several dozen posts from a discussion about survival being a goal, to bat ears and eyes, to echolocation, back to bat ears, and now to unknowable purpose in evolution. The common theme is that Keith has a lot of suggestive questions about evolution, indicating both that he has a poor grasp of the fundamentals and that he has an agenda to unfurl. I've asked him thrice now pointed requests for him to reveal his research plan to his own questions -- only to have received no response. This should indicate to any reader that Keith is not really interested in expanding knowledge about things he is questioning. Rather he is here to attack what he doesn't understand. One thing is for sure: this topic is not evolving.

Keith

The point that I've already made, and which is apparently being ignored, is that in my illustration of the 300 monkeys collaborating on the writing of equal portions of the London phone book, if any one of the monkeys gets a bit too far behind or too far ahead of the rest of the monkeys, the whole project is trashed.

The way this example relates to bat ear development is that as far as we know, bat ears aren't just complicated now, they were nearly as complicated ten years ago, one hundred years ago, and even ten thousand years ago. And miraculously, each of these individual ear parts has kept up its developmental pace in perfect sync with all of the other ear parts. At every stage in the ear development all of the ear parts MUST be developing on the exact same schedule and be working together or else that species of bat is gone forever.

Keith

Keith

You can only say in hindsight which traits may have been beneficial, or at least perhaps, neutral. Nothing more can be known.

Keith

Principia

Not quite. One only needs to read page 1 of this thread to see that the analogy here to evolutionary processes is poor, as has been pointed out to you. Do we need to rehash this argument again for you?

Show me how we know that bat ears were "nearly as complicated" ten thousand years ago. Define complexity. Once again, where is the evidence that all ear parts are developing simultaneously? EDIT: where is the evidence that without bat ears, bats are "gone forever?"

Keith, these questions to you keep coming up again and again. You are obviously unsatisfied with current scientific progress in this area. So, once again, I ask you to provide us with your research program that provides the facts to show us why bat ears are indeed "miraculous."

Happy Wonderer

OK, if I accept that statement (which I don't) then so what? We are talking about a historical process, whether it is a bacteria colony started ten days ago, or the evolution of vertabrates. There is nothing illogical about talking about harmful, neutral, or beneficial traits in a population.

The statement is not true, however. We can detect beneficial traits in populations today. The proof is in the pudding, so to speak, a trait that is benefical for reproduction will by definition be over-represented in the population (given enough generations.)

Keep in mind that some traits (such as white fur in bears) may involve a simple transcription error, and can rise independently. White bears do better in the snow, but there is no need for 'nature' keep a "reserve" of white fur bears alive just in case there is an ice age. Some bears are going to be born with the "white fur" defect regardless; in an ice age instead of starving they become much more efficient hunters than their brown fur peers. By the nature of the defect, the 'brown' fur trait can be turned on again by a later transcription error; if it is useful because the environment has changed then the brown bear will become dominant again.

It doesn't seem to me to matter at all whether we know today if the 'white' fur allele is beneficial or neutral in the future. We can only say if it is beneficial today and can see (by population representation) if it was beneficial in the past. The fact that the B.C. white grizzley is rare indicates that it is not a beneficial allele for that environment.

(I don't actually know the genetic details of fur colors or much else for that matter, this is a hypothetical example.)



HW

I'm sure that you know all that I have written here, so I must be misunderstanding your position.

Happy Wonderer

Erm, are you being serious? 10KYA isn't all that long, evolution-wise. Ten and 100 years is nothing at all. EDIT: Once echolocation has reached a point of utility, why would you expect it to continue to change? Would there be any advantage in having a system sensitive enough to detect microbes, when all you need to be able to detect are the insects that you eat?

I see no evidence presented that "individual ear parts have kept up developmental pace in perfect sync" or any evidence that they would have to. All the improvement has to do to become an advantage is to not make something important worse. Mechanical and biological systems have a lot of flexibility; you can change the size of one bone slightly without throwing the whole thing out of whack. If that change is an improvement it may eventually became part of the population.


HW

EDIT2: There is a really important point that I think you are missing. Even if the parts don't work for a particular bat because of a mutation, that is too bad for that individual bat but not too bad for that species of bat.

Keith

How did any particular species of mouse-like creature realize that it needs to transform itself into a bat-like creature in order to survive? How did this mouse-like animal know that it MUST begin developing a highly sophisticated ear structure right now, for its future survival needs? If neither the mouse-like creature or nature knew anything about the future, how, and why, did this intricately planned, superbly designed, well orchestrated, intelligent, and obviously purposeful chain of events occur? Did it just happen?

Keith

Starboy

Keith, where you been this entire thread. No one is putting forth that creatures transform themselves. They change through an interaction between environment and genetics. It is not that the creature knows to do it, it is more like, when the rock is in the sun, it warms up through natural processes. In the spirit of your question, it would be like asking ‘How does the rock know to warm up?’ This is an obviously stupid question. Evolution is a natural reaction to the environment that makes use of random processes. If the creature lived in a vacuum it would not have ears and would have developed some other mechanism for locating its prey at night under all conditions. Who knows, maybe it might evolve radar, but if it is a question of surviving or not, if it does survive it will be because it has evolved in a way that allows it to capture its prey.

What I find interesting about your approach is that you do not seem to take any notice of the overwhelming number of creatures that did not make it. Why do you ignore them? What purpose do they serve? How do you explain why the vast majority of species have become extinct?

Starboy

Keith

The space shuttle is more complex than the first airplane built and flown by the Wright brothers. This is what I meant by complexity. I don't want to get too technical, or too long-winded.

It is self evident that to the extent that a species of bat requires its ears to survive, it will need every essential part of the ear to be working. If one of these essential ear parts has not kept up its developmental pace at any point along the development of the ear (in relation to all the other ear parts), the ear won't function, and the species will not survive.

Keith