In order to believe Micro but not Macro evolution, you must...

[PeterMaclellan]

Point to the process that stops micro evolution and show evidence for it's existence. All Macro-evolution consists of is micro-evolution plus time and many generations, so in order to believe that Macro-evolution does not occur, there must be some sort of process that contains micro-evolution and at some point stops it before speciation occurs. I would like to know what this process is and what evidence exists suggesting it's existence.

 

[ChordatesLegacy]

Even creationists believe in micro evolution, and you are right all macro evolution is, is macro evolution plus time.

There are no known or perceived mechanisms for stopping micro evolution, if there where life on this planet would never have got past the single cell stage.

Perhaps this is why creationists want let go of their young Earth nonsense.

 

[CACTUSJACKmankin]

Point to the process that stops micro evolution and show evidence for it's existence. All Macro-evolution consists of is micro-evolution plus time and many generations, so in order to believe that Macro-evolution does not occur, there must be some sort of process that contains micro-evolution and at some point stops it before speciation occurs. I would like to know what this process is and what evidence exists suggesting it's existence.

i call it the kind boundary. They have no answer and until they do there is no reason to doubt macroevolution because the time is infact there.

 

[sfs]

Point to the process that stops micro evolution and show evidence for it's existence. All Macro-evolution consists of is micro-evolution plus time and many generations, so in order to believe that Macro-evolution does not occur, there must be some sort of process that contains micro-evolution and at some point stops it before speciation occurs. I would like to know what this process is and what evidence exists suggesting it's existence.

This is not an argument that I find persuasive. There is already a well-known process that stops most microevolution: the nonviability of most points in genome space. The space of possible genomes is very large, of high dimensionality, and (because of developmental constraints) can only be traversed by small steps. There is no way to determine from first principles whether viable regions in this space consist of isolated islands or an interconnected web. As far as I can tell, whether or not large-scale macroevolution is possible is an empirical question.

 

[CACTUSJACKmankin]

This is not an argument that I find persuasive. There is already a well-known process that stops most microevolution: the nonviability of most points in genome space. The space of possible genomes is very large, of high dimensionality, and (because of developmental constraints) can only be traversed by small steps. There is no way to determine from first principles whether viable regions in this space consist of isolated islands or an interconnected web. As far as I can tell, whether or not large-scale macroevolution is possible is an empirical question.

any base in the genome can be incorrectly copied. Where's the restraint?

 

[PeterMaclellan]

In my overly simplistic mind I saw the macro/micro debate as working something like this.

Say you have a number 1111 and this number represents its genetic code, each time it reproduces, theres a chance one of the numbers can change, going up one or down one. Lets say speciation occurs when the new number shares no numbers with the original.

so it could go (leaving out all the hundreds of thousands of identical offspring and the ones who die horribly)

1111
1112
0112
0111
0121
0131
0231
0230

At this point speciation has occured and the new number has nothing in common with the original one, all through incremental steps. Obviously theres more to it, but it demonstrates how Macro-Evolution (the change from an original to something new and different) happens by incremental Micro-evolution (individual mutations)

If there is a genetic reason why this can't happen, what is it?

 

[Hnefi]

This is not an argument that I find persuasive. There is already a well-known process that stops most microevolution: the nonviability of most points in genome space. The space of possible genomes is very large, of high dimensionality, and (because of developmental constraints) can only be traversed by small steps. There is no way to determine from first principles whether viable regions in this space consist of isolated islands or an interconnected web. As far as I can tell, whether or not large-scale macroevolution is possible is an empirical question.

Not at all. What you are saying would be true if evolution was a local optimization method (commonly referred to as a "greedy" method in mathematics). Such methods tend to get stuck in local minima of the fitness function (which, in the case of evolution, is reproductive success) and would not be able to make creatures evolve beyond a certain form.

But evolution is not a greedy method; it is stochastic. As such, it can (and does) escape from local minima and approach better minima by temporarily approaching a suboptimal solution.

This method always finds the best solution. It is, in fact, mathematically proven that this is so and it is sometimes used in mathematics and computer science (under the name genetic algorithms) to optimize problems that can be expressed as parameter choices precisely for this reason. However, it is also a horribly, horribly inefficient method; for almost any conceivable problem, there are far more efficient solutions at hand, so genetic algorithms rarely find their way into actual applications.

Nature, however, doesn't have a choice. So how does it get around the extreme inefficiencies of the algorithm and the astronomical size of the solution space? Simple. Massive parallellization and geological timescales. Evolution will find a better solution to the combination of genes if given enough trials; those trials have been running on a global scale for at least three billion years now, with billions of trials occurring every second (if you count all the bacteria). Now that's supercomputing - with processing power like that, even something as inefficient as evolution will perform nigh-unimaginable optimizations to improve the fitness of living things.

 

[TheManeki]

i call it the kind boundary. They have no answer and until they do there is no reason to doubt macroevolution because the time is infact there.

Maybe that's why they dig in their heels and insist the earth is ~6000 years old.

 

[CACTUSJACKmankin]

Maybe that's why they dig in their heels and insist the earth is ~6000 years old.

Oh, i think it's a big reason why they stick to that time frame. not enough time = no macroevolution.

 

[AV1611VET]

Point to the process that stops micro evolution and show evidence for it's existence. All Macro-evolution consists of is micro-evolution plus time and many generations, so in order to believe that Macro-evolution does not occur, there must be some sort of process that contains micro-evolution and at some point stops it before speciation occurs. I would like to know what this process is and what evidence exists suggesting it's existence.

[bible]Psalm 74:17[/bible]

God is the God of boundaries; and even though nature is hostile to God's creation, she is obedient to God, Himself.

The part I highlighted in red, I don't understand. I thought micro-evolution is speciation.

Did you mean "stops it before a new genera is created"?

Correct me if I'm wrong, but I'm under the assumption that:

• Micro-evolution = new species.
• Macro-evolution = new genera.

 

[Vene]

Maybe the way that creationists have used it, but the term in biology is more like:
microevolution: change within a species
macroevolution: speciation

 

[sfs]

any base in the genome can be incorrectly copied. Where's the restraint?

The restraint is that many of the new versions of the genome, the ones you get after the incorrect copying, are not viable or are at least highly deleterious. In order to get from point A to point B by evolution, there has to be a connected path of viable genomes, and you just don't know that a priori.

 

[sfs]

In my overly simplistic mind I saw the macro/micro debate as working something like this.

Say you have a number 1111 and this number represents its genetic code, each time it reproduces, theres a chance one of the numbers can change, going up one or down one. Lets say speciation occurs when the new number shares no numbers with the original.

so it could go (leaving out all the hundreds of thousands of identical offspring and the ones who die horribly)

1111
1112
0112
0111
0121
0131
0231
0230

At this point speciation has occured and the new number has nothing in common with the original one, all through incremental steps. Obviously theres more to it, but it demonstrates how Macro-Evolution (the change from an original to something new and different) happens by incremental Micro-evolution (individual mutations)

If there is a genetic reason why this can't happen, what is it?

The genetic reason would be that genome 0111 is embryonic lethal, for example.

There is no question that speciation is genetically possible, since it can involve fairly small genetic changes. What I'm saying is that you cannot tell from first principles (i.e. from our knowledge of genetics, cell biology and developmental biology) just how far an organism can change and still be viable.

 

[guzman]

Even creationists believe in micro evolution, and you are right all macro evolution is, is macro evolution plus time.

There are no known or perceived mechanisms for stopping micro evolution, if there where life on this planet would never have got past the single cell stage.

Perhaps this is why creationists want let go of their young Earth nonsense.

Professor Allen MacNeil,

http://www.uncommondescent.com/inte...ionary-biologist-declares-neo-darwinism-dead/

Furthermore, I think the paleontological and genetic/developmental evidence is sufficiently robust at the present time to assert that macroevolution cannot be simply reduced to microevolutionary processes working over longer periods of time. There appear to be macroevolutionary mechanisms that operate somewhat differently that those traditionally placed under the heading of microevolution.

so much for this thread.

 

[sfs]

Not at all. What you are saying would be true if evolution was a local optimization method (commonly referred to as a "greedy" method in mathematics). Such methods tend to get stuck in local minima of the fitness function (which, in the case of evolution, is reproductive success) and would not be able to make creatures evolve beyond a certain form.

But evolution is not a greedy method; it is stochastic. As such, it can (and does) escape from local minima and approach better minima by temporarily approaching a suboptimal solution.

This method always finds the best solution.
[...]
Now that's supercomputing - with processing power like that, even something as inefficient as evolution will perform nigh-unimaginable optimizations to improve the fitness of living things.

There seem to be a couple of confusions here. First, evolution is not a global optimization algorithm; all species are in the vicinity of local optima, not some global optimum (if that even means anything biologically). Second, while evolution is stochastic, it is strictly a local search procedure, at least in metazoans. Evolution will explore slightly suboptimal solutions, but strongly suboptimal ones will never last long enough for a species to move through that trough, and lethal solutions are impassible. Are there workable paths between the regions of viability? That question can only be answered empirically at this point, not by the kind of abstract argument you're using here.

Larger jumps (large insertions and deletions, for example) are possible, but as their effect gets larger, the probability of their hitting a viable solution drops sharply. This is true not only because the great majority of genome space is not viable (so picking random points is a very bad strategy), but also because offspring inherit not only a (possibly modified) genome from their parents, but also a developmental environment (e.g. the chemical environment of a fertilized egg). That environment is unlikely to support development of a very different organism.

 

[sfs]

Professor Allen MacNeil,

http://www.uncommondescent.com/inte...ionary-biologist-declares-neo-darwinism-dead/

Furthermore, I think the paleontological and genetic/developmental evidence is sufficiently robust at the present time to assert that macroevolution cannot be simply reduced to microevolutionary processes working over longer periods of time. There appear to be macroevolutionary mechanisms that operate somewhat differently that those traditionally placed under the heading of microevolution.

so much for this thread.

While this thread has real problems, you have not raised one of them. The claim in the OP was that microevolution continued long enough will produce macroevolution. The quote you produced does nothing to refute that claim. What the quote is claiming is not that microevolution doesn't lead to macroevolution, but that the actual course of macroevolution is not governed solely by microevolutionary processes.

 

[CACTUSJACKmankin]

The restraint is that many of the new versions of the genome, the ones you get after the incorrect copying, are not viable or are at least highly deleterious. In order to get from point A to point B by evolution, there has to be a connected path of viable genomes, and you just don't know that a priori.

The genetic reason would be that genome 0111 is embryonic lethal, for example.

There is no question that speciation is genetically possible, since it can involve fairly small genetic changes. What I'm saying is that you cannot tell from first principles (i.e. from our knowledge of genetics, cell biology and developmental biology) just how far an organism can change and still be viable.

Deleterious mutations are, for the most part, a nonissue for evolution because natural selection gets rid of them. it doesnt matter if beneficial mutations account for 0.000001% of mutations, it's enough because natural selection will incorporate them.

 

[sfs]

Deleterious mutations are, for the most part, a nonissue for evolution because natural selection gets rid of them. it doesnt matter if beneficial mutations account for 0.000001% of mutations, it's enough because natural selection will incorporate them.

Yes. So? The argument of the OP amounts to the claim that there are always beneficial mutations that take you farther away from the starting genotype for an organism. No one has showed that that is the case. If it isn't, then all beneficial mutations are going to do is permit an organism to track modest changes in the environment, or compensate for deleterious mutations that may have fixed by chance.

 

[CACTUSJACKmankin]

Yes. So? The argument of the OP amounts to the claim that there are always beneficial mutations that take you farther away from the starting genotype for an organism. No one has showed that that is the case. If it isn't, then all beneficial mutations are going to do is permit an organism to track modest changes in the environment, or compensate for deleterious mutations that may have fixed by chance.

evolution works by modest changes. large changes = modest changes over time.

 

[Hnefi]

There seem to be a couple of confusions here. First, evolution is not a global optimization algorithm; all species are in the vicinity of local optima, not some global optimum (if that even means anything biologically).

This is true. It doesn't really affect the argument, however.

Second, while evolution is stochastic, it is strictly a local search procedure, at least in metazoans. Evolution will explore slightly suboptimal solutions, but strongly suboptimal ones will never last long enough for a species to move through that trough, and lethal solutions are impassible. Are there workable paths between the regions of viability? That question can only be answered empirically at this point, not by the kind of abstract argument you're using here.

I agree. I also agree with your point that we can only deduce that evolution works in nature through empirical observation; you are correct (AFAIK) in stating that we cannot say from first principles alone whether or not a certain hypothetical branch of evolution is feasible.

When it comes to not exploring strongly suboptimal solutions, that is correct in a stable environment. However, if the environment changes relatively drastically (as it does every now and then), the current configuration of genomes will be strongly suboptimal and the search for new minima will be swift and highly stochastic. It's a bit like annealing in that way; the closer the system gets to a minimum, the lesser the stochastic factor becomes.

Larger jumps (large insertions and deletions, for example) are possible, but as their effect gets larger, the probability of their hitting a viable solution drops sharply. This is true not only because the great majority of genome space is not viable (so picking random points is a very bad strategy), but also because offspring inherit not only a (possibly modified) genome from their parents, but also a developmental environment (e.g. the chemical environment of a fertilized egg). That environment is unlikely to support development of a very different organism.

Very true. I agree with all of your points. However, it should be noted that most changes in the genome - even large changes - does not hinder the possibility to reproduce. As long as the reproductive systems themselves remain relatively unaltered (as they have for a very, very long time), we can get away with all sorts of large-scale changes in the individual - even entire missing (or added) chromosomes. The chances of such a mutation to be beneficial is, as you say, vanishingly small so you are correct in stating that there needs to be a reasonable "path" between any two points in the evolutionary history of a species. And there is; that's why we get a nested hierarchy.

So basically, I agree with you: we cannot, from a quick look at the evolutionary process, determine whether or not a certain hypothetical evolutionary path is viable. That, however, is not an argument against macroevolution, because the empirical evidence to compensate for this is available, thanks to paleontology and comparative genetics.