Comments on: Natural vs. unnatural selection: Consider the ceaseless yap of the lap dog and be warned

By: Flannery

Flannery — Thu, 25 Jun 2009 23:23:43 +0000

To #45: Your conclusion that “many, many wild animals fail to survive in a man-made environment” is actually not true. Your having the same difficulty Darwin did. Darwin
saw competition as taking place between individuals while Wallace saw competition as taking place between populations. Darwin focused on individual struggles for existence while Wallace concentrated on population growth as the powerful modifying force in nature. Wallace saw evolution taking place not in an individual but in a demographic context. So to your point: Yes, wolf A or wolf B may fail to survive in a man-made environment, but it is simply wrong to say that as a group wolves cannot survive-or many other wild animals for that matter-cannot as a group survive in such environments. In fact, the artificial protective factor actually enhances their longevity with fewer exposures to parasites, bacteria, etc.

As to #46, Wallace writes “an equal chance of continuance” not survival. He’s speaking of breeds once domesticated not “an eqaul chance” amongst a set of unbred or potentially bred animals. The chances of continuance are largely equaled out by the protection accorded by the breeder. This doesn’t happen in the wild.

By: Nakashima

Nakashima — Thu, 25 Jun 2009 15:19:57 +0000

in the domesticated animal all variations have an equal chance of continuance;

I’m sure these really are Wallace’s words, after he is using a semi-colon correctly. However, he is quite wrong, since the whole point of artificial selection as an example for Darwin was that the breeder will only allow certain animals to breed, even if all those born are allowed to live (and no guarantees there).

By: Mark Frank

Mark Frank — Thu, 25 Jun 2009 11:08:42 +0000

#43 (and others)

None of these reflections on greyhounds throw any light on what Denyse is saying. There is a mysterious bit of logic that appears to go:

Domestic animals are selected to prosper in man-made environments

Domestic animals cannot survive in the wild

Therefore selection of domestic animals is not really like natural selection

It is an obviously fallacious argument. Few species are good at surviving in an environment in which they were not selected. Wolves and many, many wild animals fail to survive in a man-made environment.

By: Flannery

Flannery — Thu, 25 Jun 2009 09:32:58 +0000

PS-It would appear the original greyhound comment was from O’Leary (the string gets a little confusing, but the statements above “Anyway, Flannery comments” are O’Leary’s and not mine). At any rate, my comments immediately above still stand.

By: Flannery

Flannery — Thu, 25 Jun 2009 09:23:56 +0000

I just looked at this thread, but this one goes to “Mivart” #7. Mivart writes, “Greyhounds are perfectly capable of taking down prey (and thus surviving in the wild despite what Michael Flannery thinks).” First of all I made no comment whatsoever about greyhounds, and in reference to natural selection, these are Wallace’s ideas not necessarily my own. In any case, I suppose Mivart’s intended point is that greyhounds are an example of a domesticated animal that actually could survive in the wild. But the greyhound is a poor example of true domestication. Cynthia Branigan’s book, The Reign of the Greyhound, points out that the greyhound probably dates to ancient times when early humans and dogs living on the African plains began living together symbiotically. Stone Age peoples, according to Branigan, probably didn’t conscously breed dogs to create greyhounds, but rather recognized that dogs with longer legs were faster and these faster dogs could be of real value. Long-legged dogs who were faster were likely kept together were they would naturally breed together. So really the greyhound’s existence is more akin to true natural selection than it is conscious domestication and hybridization through breeding. I think Wallace’s comments are not in the least compromised by the example of the greyhound since the very trait (i.e., speed) occured naturally in the original breeding pairs.

By: Mark Frank

Mark Frank — Wed, 24 Jun 2009 06:53:43 +0000

#34

Nakashima

I am sorry. My comment was not clear. I was responding to Matteo’s bizarre comment:

“I note that the defenders of unguided evolution are jumping in and pointing out that natural selection really isn’t the same as artificial selection, and that all the disadvantages of artificial selection don’t apply to natural selection.”

This was the behaviour I was referring to. I offered your comment #27 as a counter-example.

By: Nakashima

Nakashima — Wed, 24 Jun 2009 00:44:24 +0000

Mr Frank,

Where did you note this behaviour by defenders of unguided evolution?

I’m sorry, I don’t know what ‘this behaviour’ refers to in the sentence you quoted from my message @27:

“This does not change the validity of the lesson that artificial selection is as much an evolutionary process as natural selection,”

By: magnan

magnan — Mon, 22 Jun 2009 20:42:37 +0000

Mutation is the limiting factor and the primary source of variation. Recombination seems to be the basic variational mechanism exploited by plant and animal breeders. This is basically the reshuffling of existing genes. Breeding experiments have shown strict limits to how far the phenotypical modification due to recombination can progress for a given species using artificial selection. Another reason genetic recombination couldn’t be random and unlimited is because if it were, we would expect extremely high rates of birth defects and infant mortality. If recombination were the almost unlimited source of variation in addition to mutation, one would expect no such limits to be demonstrated, and nothing like the very low rates of birth defects actually observed. Instead, the injection of mutations is required to actually create the possibility of macroevolutionary innovation.

The usual major speculated mutational mechanisms for the large differences between species are gene duplication followed by subsequent mutation, mutations in regulatory regions, and mutations in “selector genes” high in developmental heirarchies. None of these mutational mechanisms can avoid the basic complex specified information problem of macroevolution.

The bottom line: dog breeding is irrelevant to macroevolution.

By: ScottAndrews

ScottAndrews — Mon, 22 Jun 2009 20:22:57 +0000

Mark Frank:
If we’re going to define adaptation as any genetic change for any purpose, whether those of the animal or the breeder, that’s okay. I can’t see a reason to pick on the terminology we use to describe how canines evolve into slightly different canines.

By: Mark Frank

Mark Frank — Mon, 22 Jun 2009 19:16:56 +0000

#36 part 2.

“If they were bred for domestication, how can that be seen as an adaptation on their part? Being caught, put in cage with another specimen, and made to reproduce is not a demonstration of adaptability. It’s a bit like suggesting that I adapted to look like both my parents.”

The adaptation is the changes that took place as a result of being forced to reproduce. When that did not resulted in adapations that were useful to man they tended to end up as dinner (without further reproduction). Where the adaptatios were useful the species thrived as cows, dogs, sheep etc have thrived way beyond most wild mammals.

I don’t get your last sentence at all.