If you accept microevolution

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jamesmorlock
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If you accept microevolution

Post #1

Post by jamesmorlock »

Simply because they are identical.

Consider an analogy:

Imagine that you can travel across the universe by walking. You have an infinite amount of time to do this, but you must make your journey by taking small steps. You have no destination, but you can go anywhere and you must never stop walking.

A thousand years pass. Where are you now? Further.
A million years pass. Where are you now? Even Further.
A billion years pass. Where are you now? Far, far away.

For every iteration of time, you will have traveled further and further. It is inevitable, for every small step takes you further. It is not possible to not travel far.

Microevolution is the small step. Macroevolution is the collective of small steps over a large period of time.

When walking for billions of years, how can you not be far away from your starting point?
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Post #11

Post by sfs »

Goat wrote: But, yes it does hold.... since 'macro-evolution' is the accumulation of small changes.
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.

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Post #12

Post by Deadclown »

Nothing prevents mutations from happening, but natural selection prevents most mutations with phenotypic effect from sticking around in the population, since they are usually deleterious. There is no reason in principle why organisms should be viable beyond a certain mutational distance from existing species. Whether too many mutations to a genome leads to a dead organism or to a new species is an empirical question(*), not one to be settled by analogies to space travel.

(*) At this point in our knowledge of biology, anyway.
Most mutations are not deleterious. The majority are neutral. Likewise, what you say, shows a very likely strawman understanding of the theory. Each individual generation would be nearly indistinguishable from the last, or even the last ten, or last one hundred. We are talking about extremely small changes that are totally and completely viable, happening over extreme time lines.

Are you making an Argument from Personal Incredulity or going for the whole 'Irreducible Complexity' thing? Maybe you think mutation means like the 'major' changes like going from a glider to a flyer in one generation?
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.
Didn't read the links I provided before replying? I already covered this.

You make common Creationist claim 902.2, "Creationists recognize that small microevolutionary changes occur, but small changes do not imply large changes, so the theory of macroevolution is unjustified."

http://www.talkorigins.org/indexcc/CB/CB902_2.html
1. This claim falsely assumes that the conclusion of macroevolution is based solely on the observation of microevolution. In fact, microevolution is just one piece of the evidence that demonstrates evolution as a whole. Other evidence includes the fossil record, patterns of similarities and differences between living species, and genetic comparisons (Darwin 1872; Theobald 2004).

2. Small changes do imply large changes under some common circumstances. If there is some selective pressure for the changes to go in one direction, the changes will add up. Such a condition can happen, for example, under a gradual climate change or in evolutionary arms races. Even if there is no selective pressure at all, the changes will tend to diverge further and further from the starting point. Small changes will not lead to large changes only

* if there is stabilizing selection for organisms to remain as they are, or
* if there is too little time for much to happen, or
* if there are genetic mechanisms limiting change.

Stabilizing selection occurs sometimes but is far from universal. We know that the earth, and life on it, is very old. And there is no hint of a mechanism to limit variation. Therefore, we expect large changes based on basic principles.
Sources are at the linked location.
I do not fear death, in view of the fact that I had been dead for billions and billions of years before I was born, and had not suffered the slightest inconvenience from it. - Mark Twain

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Post #13

Post by sfs »

Deadclown wrote:
Nothing prevents mutations from happening, but natural selection prevents most mutations with phenotypic effect from sticking around in the population, since they are usually deleterious. There is no reason in principle why organisms should be viable beyond a certain mutational distance from existing species. Whether too many mutations to a genome leads to a dead organism or to a new species is an empirical question(*), not one to be settled by analogies to space travel.

(*) At this point in our knowledge of biology, anyway.
Most mutations are not deleterious. The majority are neutral.
Most mutations with phenotypic effect, however, are not neutral, and that's what I actually wrote.
Likewise, what you say, shows a very likely strawman understanding of the theory.
Certainly possible, but unlikely based on objective considerations (e.g. the fact that I only posted on this thread because I was sleepless from jet lag, caused by traveling to Kyoto to give a talk at the annual Society for Molecular Biology and Evolution meeting).
Each individual generation would be nearly indistinguishable from the last, or even
the last ten, or last one hundred. We are talking about extremely small changes that are totally and completely viable, happening over extreme time lines.
And I'm talking about there not being any a priori way of knowing whether there actually are totally and completely viable states that are many mutational changes away existing organisms.
Are you making an Argument from Personal Incredulity or going for the whole 'Irreducible Complexity' thing? Maybe you think mutation means like the 'major' changes like going from a glider to a flyer in one generation?
No, I'm pointing out a flawed analogy about a field I study for a living.
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.
Didn't read the links I provided before replying? I already covered this.
Come again? What in any of those links contradicts what I wrote? Most microevolution does not in fact lead to macroevolution. Some does, sure, but when have I denied that?
You make common Creationist claim 902.2, "Creationists recognize that small microevolutionary changes occur, but small changes do not imply large changes, so the theory of macroevolution is unjustified."
No, I haven't made that claim at all. My claim is that a random walk is a bad analogy for evolution. Mutations randomly move species away from their present state, but natural selection tends to pull them back toward their starting point. If the environment changes, then selection can move the species to a (or near) a new optimum genome. But this process by itself need not lead to indefinite change; other processes (e.g. external factors isolating subpopulations or major environmental shifts) are required for that to happen.
1. This claim falsely assumes that the conclusion of macroevolution is based solely on the observation of microevolution. In fact, microevolution is just one piece of the evidence that demonstrates evolution as a whole. Other evidence includes the fossil record, patterns of similarities and differences between living species, and genetic comparisons (Darwin 1872; Theobald 2004).
Exactly. We didn't conclude that macroevolution happens because we observed microevolution; we concluded that it happened because species are obviously related by descent, and then we observed micoevolution and concluded that that led to macroevolution. Empirical evidence was the starting point, not a logical argument, much less an analogy.
2. Small changes do imply large changes under some common circumstances. If there is some selective pressure for the changes to go in one direction, the changes will add up. Such a condition can happen, for example, under a gradual climate change or in evolutionary arms races. Even if there is no selective pressure at all, the changes will tend to diverge further and further from the starting point. Small changes will not lead to large changes only

* if there is stabilizing selection for organisms to remain as they are, or
* if there is too little time for much to happen, or
* if there are genetic mechanisms limiting change.

Stabilizing selection occurs sometimes but is far from universal. We know that the earth, and life on it, is very old. And there is no hint of a mechanism to limit variation. Therefore, we expect large changes based on basic principles.
As stated, this argument is wrong. We observe that small changes do lead to large changes, but we don't know that from basic principles. Life could be such that prolonged selective pressure in one direction leads only to extinction. (Obviously, if this were the case, we probably wouldn't be here discussing it.)

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Post #14

Post by Deadclown »

sfs wrote:
Deadclown wrote:
Nothing prevents mutations from happening, but natural selection prevents most mutations with phenotypic effect from sticking around in the population, since they are usually deleterious. There is no reason in principle why organisms should be viable beyond a certain mutational distance from existing species. Whether too many mutations to a genome leads to a dead organism or to a new species is an empirical question(*), not one to be settled by analogies to space travel.

(*) At this point in our knowledge of biology, anyway.
Most mutations are not deleterious. The majority are neutral.
Most mutations with phenotypic effect, however, are not neutral, and that's what I actually wrote.
Likewise, what you say, shows a very likely strawman understanding of the theory.
Certainly possible, but unlikely based on objective considerations (e.g. the fact that I only posted on this thread because I was sleepless from jet lag, caused by traveling to Kyoto to give a talk at the annual Society for Molecular Biology and Evolution meeting).
Each individual generation would be nearly indistinguishable from the last, or even
the last ten, or last one hundred. We are talking about extremely small changes that are totally and completely viable, happening over extreme time lines.
And I'm talking about there not being any a priori way of knowing whether there actually are totally and completely viable states that are many mutational changes away existing organisms.
Are you making an Argument from Personal Incredulity or going for the whole 'Irreducible Complexity' thing? Maybe you think mutation means like the 'major' changes like going from a glider to a flyer in one generation?
No, I'm pointing out a flawed analogy about a field I study for a living.
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.
Didn't read the links I provided before replying? I already covered this.
Come again? What in any of those links contradicts what I wrote? Most microevolution does not in fact lead to macroevolution. Some does, sure, but when have I denied that?
You make common Creationist claim 902.2, "Creationists recognize that small microevolutionary changes occur, but small changes do not imply large changes, so the theory of macroevolution is unjustified."
No, I haven't made that claim at all. My claim is that a random walk is a bad analogy for evolution. Mutations randomly move species away from their present state, but natural selection tends to pull them back toward their starting point. If the environment changes, then selection can move the species to a (or near) a new optimum genome. But this process by itself need not lead to indefinite change; other processes (e.g. external factors isolating subpopulations or major environmental shifts) are required for that to happen.
1. This claim falsely assumes that the conclusion of macroevolution is based solely on the observation of microevolution. In fact, microevolution is just one piece of the evidence that demonstrates evolution as a whole. Other evidence includes the fossil record, patterns of similarities and differences between living species, and genetic comparisons (Darwin 1872; Theobald 2004).
Exactly. We didn't conclude that macroevolution happens because we observed microevolution; we concluded that it happened because species are obviously related by descent, and then we observed micoevolution and concluded that that led to macroevolution. Empirical evidence was the starting point, not a logical argument, much less an analogy.
2. Small changes do imply large changes under some common circumstances. If there is some selective pressure for the changes to go in one direction, the changes will add up. Such a condition can happen, for example, under a gradual climate change or in evolutionary arms races. Even if there is no selective pressure at all, the changes will tend to diverge further and further from the starting point. Small changes will not lead to large changes only

* if there is stabilizing selection for organisms to remain as they are, or
* if there is too little time for much to happen, or
* if there are genetic mechanisms limiting change.

Stabilizing selection occurs sometimes but is far from universal. We know that the earth, and life on it, is very old. And there is no hint of a mechanism to limit variation. Therefore, we expect large changes based on basic principles.
As stated, this argument is wrong. We observe that small changes do lead to large changes, but we don't know that from basic principles. Life could be such that prolonged selective pressure in one direction leads only to extinction. (Obviously, if this were the case, we probably wouldn't be here discussing it.)
Upon rereading your posts, I see what you were getting at, and apologize for misunderstanding.
I do not fear death, in view of the fact that I had been dead for billions and billions of years before I was born, and had not suffered the slightest inconvenience from it. - Mark Twain

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Post #15

Post by sfs »

Deadclown wrote: Upon rereading your posts, I see what you were getting at, and apologize for misunderstanding.
No problem. As I said, I'm short on sleep, and may not be at my clearest.

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Post #16

Post by Autodidact »

sfs wrote:
Autodidact wrote: What would prevent genetic change from accumulating indefinitely? Does DNA suddenly stop mutating at some point? How would that work? What prevents mutations from happening?
Nothing prevents mutations from happening, but natural selection prevents most mutations with phenotypic effect from sticking around in the population, since they are usually deleterious
. Not quite. Most are nuetral; neither advantageous nor deleterious. Some are negative. And a few are beneficial; those are the ones that drive evolution.
There is no reason in principle why organisms should be viable beyond a certain mutational distance from existing species
.Why not? A mutation is a mutation. How does the mutation know how many previous mutations have happened?
Whether too many mutations to a genome leads to a dead organism or to a new species is an empirical question(*), not one to be settled by analogies to space travel.
It is, and it's one that has been settled by empiricism; which is why the Theory of Evolution (ToE) is the foundation of modern Biology.
(*) At this point in our knowledge of biology, anyway.
At this point in our knowledge of Biology, we know that ToE is correct, and there is no such Biblical barrier, as well as we know anything in science.

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Post #17

Post by Goat »

sfs wrote:
Goat wrote: But, yes it does hold.... since 'macro-evolution' is the accumulation of small changes.
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.
Really??? Care to prove that claim?? If that was true, then, how do you explain ring species?
“What do you think science is? There is nothing magical about science. It is simply a systematic way for carefully and thoroughly observing nature and using consistent logic to evaluate results. So which part of that exactly do you disagree with? Do you disagree with being thorough? Using careful observation? Being systematic? Or using consistent logic?�

Steven Novella

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Post #18

Post by Autodidact »

sfs wrote:
Goat wrote: But, yes it does hold.... since 'macro-evolution' is the accumulation of small changes.
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.
This is incorrect. When enough "microevolution" happens, the two sets of organisms are different enough that Biologists, somewhat arbitrarily, draw a line and call them two different species. What distinguishes one species from another is the quantity of microevolution. In other words, to use another analogy, 1 + 1 + 1 + 1 + 1 = 5. If you add up enough ones, you can't avoid reaching 5. If you add up enough micro-evolution, you get a new species.

Btw, if you talk to a YEC long enough, it will usually* emerge that they completely accept that speciation happens. They have to, unless Noah took millions and millions of creatures on a single small boat. What most of them assert nowadays is that speciation stops at an arbitrary, undefined limit called a "kind," a category that cannot be defined and does not exist.

In other words, they accept everything about ToE. The only places they differ are:
(1) The number of original common ancestors
(2) Homo sapiens.

They tend to forget this, though, unless pressed.

*I say usually because, lacking the scientific method, they have no way to reach consensus on this or any other issue. I have met creationists, many of them Muslim, who deny that speciation happens at all. This may be because Muslims aren't worried about how many creatures they have to fit on a small wooden boat.

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Post #19

Post by jamesmorlock »

Speciation has been observed, many times, in species which reproduce and create new generations quickly. Some creationists realize this and then retrofit their argument to say that evolution has never created new "kinds", the made-up term Autodidact was talking about that they are so fond of.
Conventionally, "macroevolution" in biology means evolution at or above the level of speciation. You can have indefinite amounts of microevolution without speciation ever occurring, so accumulated microevolution need not lead to macroevolution.
I never denied this. Analogies are never perfect (they can't encompass everything, like we already said), but that doesn't mean it's a *bad* analogy. If you've got a better one then provide it.
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Post #20

Post by Question Everything »

jamesmorlock wrote:Speciation has been observed, many times, in species which reproduce and create new generations quickly. Some creationists realize this and then retrofit their argument to say that evolution has never created new "kinds", the made-up term Autodidact was talking about that they are so fond of.
I wonder what they do when you show them the DNA evidence that all living things have a common ancestor? DNA sequencing and comparism is one of the closest things to absolute proof that you can have in science. It shows very clearly what is related to what, and how long ago their common ancestor was. And, it is the same process to see how closely related two humans are (for example, to establish paternity) that is also used to see how closely related two species are

In other words, not only are we related to monkeys swinging from trees, we are related to the trees they are swinging from. Sorry, that's a fact. Yes, I can support this claim.
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