What evidence is there for evolution being non-random?

[mijopaalmc]

The title of the thread says it all. I understand that evolution is a process directed through natural selection, but, as I understand it, natural selection is based on the probability, not certainty, of an organism with a specific "fitness complement" (i.e., the set of genes that contribute to its survival and reproduction relative to others of the same species). An individual whose fitness complement confers a greater chance of survival and reproduction is only more likely to survive and reproduce that one with a fitness complement that a lesser chance, but the survival and reproduction is not determined to such an extent that all the individuals with a specific fitness complement don not survive and reproduce. Thus, it is possible for one individual with a certain fitness complement to survive while another individual with the same fitness complement doesn't.

I only ask this, because I am thoroughly disappointed in the evidence that I have received from the posters in this thread. No-one to my knowledge has either explained how a process that operates on probability is non-random or directed me toward a resource that does. They all seem to be more interested, as is most of the literature on the internet that doesn't specifically deal with non-random genetic processes such as mutation and unequal cross over, in refuting the creationist straw man that holds that organisms in their current state are far too complex to have arisen by chance.

I would appreciate it if someone could point me toward some literature (especially of the peer-reviewed kind)that explain clearly and concisely why evolution is non-random.

 

[JoeTheJuggler]

Take a look at this thread: http://www.internationalskeptics.com/forums/showthread.php?t=82089

I'm pretty sure, though, that you've been given this information already.

An individual whose fitness complement confers a greater chance of survival and reproduction is only more likely to survive and reproduce that one with a fitness complement that a lesser chance, but the survival and reproduction is not determined to such an extent that all the individuals with a specific fitness complement don not survive and reproduce. Thus, it is possible for one individual with a certain fitness complement to survive while another individual with the same fitness complement doesn't.

As to this more specific concern, you can look at it this way: every organism that survives to reproduce is fit (at least enough to survive and reproduce in its current environment). That other equally "fit" individuals don't survive doesn't affect the statement I just made.

Also, since the measure of fitness is how well they survive to reproduce, how do you know these other individuals are equally as fit?

It could be that they are very closely related, and thus share many of the same genes. This is more or less the argument for the evolution of altruism. An individual might risk his own survival for the good of others, and it makes sense from a genetic standpoint (the altruistic trait is probably more frequent among those his sacrifice saved, so he has helped to pass that trait along, albeit indirectly).

 

[Dr Adequate]

Well, the evidence would be that organisms are in fact adapted to their environment.

Also, you can just do the math.

(Taken from the SkepticWiki article on [swiki]Genetic Drift[/swiki].)

Or you could consider the fact that genetic algorithms work.

 

[mijopaalmc]

Take a look at this thread: http://www.internationalskeptics.com/forums/showthread.php?t=82089

I'm pretty sure, though, that you've been given this information already.


As to this more specific concern, you can look at it this way: every organism that survives to reproduce is fit (at least enough to survive and reproduce in its current environment). That other equally "fit" individuals don't survive doesn't affect the statement I just made.

Also, since the measure of fitness is how well they survive to reproduce, how do you know these other individuals are equally as fit?

It could be that they are very closely related, and thus share many of the same genes. This is more or less the argument for the evolution of altruism. An individual might risk his own survival for the good of others, and it makes sense from a genetic standpoint (the altruistic trait is probably more frequent among those his sacrifice saved, so he has helped to pass that trait along, albeit indirectly).

Well, the evidence would be that organisms are in fact adapted to their environment.

Also, you can just do the math.

[qimg]http://www.skepticwiki.org/images/2/2e/Selective_advantage.jpg[/qimg]

(Taken from the SkepticWiki article on [swiki]Genetic Drift[/swiki].)

Or you could consider the fact that genetic algorithms work.

I know you guys hate when I do this but:

1. inundating me with vast amounts of data only a small portion of which is relevant to the question I asked, does not answer my question; providing a link to a specific page would be much more helpful and would show good faith
   
2. organisms adapting to their environment in no way proves that evolution is non-random; the mean fitness of a population increasing over time only tells us that the frequency of less fit individuals is increasing and that can occur randomly.

I will consider the information that you provide, but it will take me a while to assimilate it all so I will not be quick in responding, a fact that seemed to get me in trouble (not necessarily with anyone who has posted thus far) the lat time we interacted.

 

[I less than three logic]

This is heading down the same path of nonsense as the other thread. First, define exactly what you mean when using the term random.

 

[Taffer]

[*]organisms adapting to their environment in no way proves that evolution is non-random; the mean fitness of a population increasing over time only tells us that the frequency of less fit individuals is increasing and that can occur randomly.
[/LIST]

But it always happens in a fixed ecosystem, doesn't it? If it was random, would you not expect it to sometimes not happen?

 

[Walter Wayne]

Well, the evidence would be that organisms are in fact adapted to their environment.

Also, you can just do the math.

[qimg]http://www.skepticwiki.org/images/2/2e/Selective_advantage.jpg[/qimg]

(Taken from the SkepticWiki article on [swiki]Genetic Drift[/swiki].)

See the word probability on the graph?

Or you could consider the fact that genetic algorithms work.

I addressed this in the other thread.

 

[Walter Wayne]

But it always happens in a fixed ecosystem, doesn't it? If it was random, would you not expect it to sometimes not happen?

It is how it adapts that is important, and which species adapt. If I roll a standard six-sided die, in always comes up between 0 and 7.

In a fix eco-system can you guarantee which species will win out, and what that species will look like in the end? Do you think you could if you had a sufficiently advanced model and good information on the start conditions.

I'll use the disease analogy again, if you had three species (A, B and C) competing for the same resources, and a disease infecting one (A) do you think whether the disease mutated to infect disease B or C first might have an effect on which species is more successful? Do you think which species is most successful will affect the evolution of the species around it?

 

[davidsmith73]

Adaptive mutation


http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&dopt=Abstract&list_uids=11433357

 

[Taffer]

It is how it adapts that is important, and which species adapt. If I roll a standard six-sided die, in always comes up between 0 and 7.

Not quite. It's like saying "4 and above is a gain in mean fitness", and it always comes up 4 or above.

In a fix eco-system can you guarantee which species will win out, and what that species will look like in the end? Do you think you could if you had a sufficiently advanced model and good information on the start conditions.

Depends. There is some indication that mutations are not nearly as random as we think. After all, we already understand the mechanisms behind most mutations, and none seem to involve anything "quantum".

I'll use the disease analogy again, if you had three species (A, B and C) competing for the same resources, and a disease infecting one (A) do you think whether the disease mutated to infect disease B or C first might have an effect on which species is more successful?

I don't quite understand your question. Are you asking "is species fitness affected by diseases?" or are you asking "if disease "A" becomes disease "B" or "C", will it have an effect on the fitnesses of species B and C"?

Do you think which species is most successful will affect the evolution of the species around it?

Yes, of course. All ecosystems have finite resources, so unless every single resource used by both species is not shared, then the fitness of one species will affect the others.

 

[l0rca]

The title of the thread says it all. I understand that evolution is a process directed through natural selection, but, as I understand it, natural selection is based on the probability, not certainty, of an organism with a specific "fitness complement" (i.e., the set of genes that contribute to its survival and reproduction relative to others of the same species). An individual whose fitness complement confers a greater chance of survival and reproduction is only more likely to survive and reproduce that one with a fitness complement that a lesser chance, but the survival and reproduction is not determined to such an extent that all the individuals with a specific fitness complement don not survive and reproduce. Thus, it is possible for one individual with a certain fitness complement to survive while another individual with the same fitness complement doesn't.

I only ask this, because I am thoroughly disappointed in the evidence that I have received from the posters in this thread. No-one to my knowledge has either explained how a process that operates on probability is non-random or directed me toward a resource that does. They all seem to be more interested, as is most of the literature on the internet that doesn't specifically deal with non-random genetic processes such as mutation and unequal cross over, in refuting the creationist straw man that holds that organisms in their current state are far too complex to have arisen by chance.

I would appreciate it if someone could point me toward some literature (especially of the peer-reviewed kind)that explain clearly and concisely why evolution is non-random.

Read The Extended Phenotype, by Richard Dawkins.

Because I'm the sort, I recommend highly that you use a local library to get the book, and not to buy it.

 

[Walter Wayne]

Adaptive mutation


http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&dopt=Abstract&list_uids=11433357

A basic principle of genetics is that the likelihood that a particular mutation occurs is independent of its phenotypic consequences.

My emphasis

First even if the likelihood is dependent, that doesn't mean non-random by technical and some non-technical definitions of random. Also the article doesn't appear to preclude other mutations outside the adaptive mutations.

They speak of finding mutations triggered by stress, however, they don't suggest in the summary that all are triggered by stress.

Unfortunately I don't subscribe or I would read the artivle.

 

[Taffer]

My emphasis

First even if the likelihood is dependent, that doesn't mean non-random by technical and some non-technical definitions of random. Also the article doesn't appear to preclude other mutations outside the adaptive mutations.

They speak of finding mutations triggered by stress, however, they don't suggest in the summary that all are triggered by stress.

Unfortunately I don't subscribe or I would read the artivle.

Ok, you're gonna have to define "random".

 

[I less than three logic]

Ok, you're gonna have to define "random".

Thats what I said.

This is heading down the same path of nonsense as the other thread. First, define exactly what you mean when using the term random.

See.

 

[Walter Wayne]

Not quite. It's like saying "4 and above is a gain in mean fitness", and it always comes up 4 or above.

Which is random.

Depends. There is some indication that mutations are not nearly as random as we think. After all, we already understand the mechanisms behind most mutations, and none seem to involve anything "quantum".

They don't involve molecular bond strengths? Whether a hydrogen resituates itself on a molecule is a probalistic function.

I don't quite understand your question. Are you asking "is species fitness affected by diseases?" or are you asking "if disease "A" becomes disease "B" or "C", will it have an effect on the fitnesses of species B and C"?

Basically. If mutation is random then if it jumps to species B or C first it will give on a leg up.

Yes, of course. All ecosystems have finite resources, so unless every single resource used by both species is not shared, then the fitness of one species will affect the others.

 

[davidsmith73]

My emphasis

First even if the likelihood is dependent, that doesn't mean non-random by technical and some non-technical definitions of random. Also the article doesn't appear to preclude other mutations outside the adaptive mutations.

They speak of finding mutations triggered by stress, however, they don't suggest in the summary that all are triggered by stress.

Unfortunately I don't subscribe or I would read the artivle.

Probability surely is not a synonym for random in this context. If the environment can trigger a biochemical cascade that alters the probability distribution of the occurance of mutations, then we have a mechanistic link between adaptation and mutation. This goes agaisnt what I believe most people refer to when they talk about the generation of mutations being random with respect to their phenotypic function. I have to admit, I don't understand the usefullness and relevance of your usage of "random".


But there is a more pertinent problem with adaptive mutation as I see it. In another abstract I've read, bacteria that begin to starve increase their expression of an error-prone DNA repair enzyme, thus increasing the rate of mutation under conditions where mutations might generate novel metabolic processes and get the cells out of trouble. But the base pairs that the polymerase targets is still random. At least, this is what the experiments appear to be saying so far - I would not rule out targeted errors just yet because I don't believe anyone is asking this question in their experiments.

 

[I less than three logic]

Read The Extended Phenotype, by Richard Dawkins.

Because I'm the sort, I recommend highly that you use a local library to get the book, and not to buy it.

I think it was people talking about Dawkins that started this "random, non-random" thing.

 

[l0rca]

I don't know why people would question evolution because Dawkins does not provide evidence. Dawkins simply assumes the reader has enough common sense to already know the evidence for evolution. Why someone would question evolution because scientists tend not to care to adjunct each sentence with tirelessly vast amounts of evidence, which any person could simply google (or go to the thread offered in the second post, or go to a museum, or go to a school teacher), sounds to me like a form of intellectual dishonesty, or intellectual laziness.

I offered that book as an education of some of the sharpest logic behind the understanding and perspective of evolution. I think the separate thread already offered is good enough evidence.

We as scientists and philosophers should not feel the need to exhale large amounts of citations and references before every sentence -- with the exception, of course, in legal and high-school matters.

 

[I less than three logic]

I have to admit, I don't understand the usefullness and relevance of your usage of "random".

Usually, the usefulness of using random instead of, say, unpredictable or chaotic when speaking of the theory of evolution, is that random is a much easier target of equivocation than other equally or more relevant terms.

 

[Taffer]

Which is random.

No, you don't get my point. You already know it's random, because I said it was a die. Instead, look at the results. Say we were looking at the results of 100 of those rolls. 99 were 4 or above, with only 1 being below. What would you conclude?

They don't involve molecular bond strengths? Whether a hydrogen resituates itself on a molecule is a probalistic function.

Some do. There are many different ways for mutations to arise. For example, indel mutations often come about from "slipping" of the DNA replication mechanisms.

Basically. If mutation is random then if it jumps to species B or C first it will give on a leg up.

If the disease decreased fitness of a population, then obviously the other population would get a similar boost in fitness.