Re: Class on Reproductive isolation

On Feb 9, 9:18 pm, "[M]adman" <g...@xxxxxxxxxx> wrote:
snip


It's a branching off of an ancestral population.   Evolution has no
particular "direction", it's change over time, and time only goes one
direction.   Evolution always produces NEW populations slightly
different from the parent population.

This is where your theory of evolution breaks down and has no proof.

There is plenty of evidence that this is correct. What do you think
'breaks down' here?


Sure
there is variation. Look at the variety of dogs. But they are /still/ dogs
descended from the original 'kind' named wolf

Yes, and that's exactly what one would expect from evolution. The
'kind' named "wolf" is from a "kind" named "Carnivores" and they are
from a "kind" named "Mammals" and so on, and so on, back to the
orginal common ancestor.



  Obviously a mutation in a population today doesn't affect it's
parent population, or make the new population that inherits that
mutation into another already existing species.   That's why talking
about "dogs turning into cats" is a strawman.   Convergent evolution
may produce a cat that has many dog like features (like a Cheetah), or
produce a dog that is very cat like (such as a Pomeranian) but will
never back up to re-produce the Miacid ancestor of both cats and
dogs.

And dogs do not turn into anything else either.

No one said they did. They don't have to 'turn into' anything else.
But they aren't exactly the same as their ancestors, which is
evolutionary change.

They will remain to be a dog
descended from wolf even after reproductive isolation

As I've been trying to explain to you, that's exactly what evolution
is all about. Wolves will remain descended from Miacids, and remain
descended from early mammals, etc. Evolution does not change one's
ancestors.



   Dogs are on their way to becoming a new species, as long as they
remain reproductively isolated.   With enough reproductive isolation
comes genetic isolation.   At that point, you have a new species.   As
the process is gradual, and continuous, it's almost impossible to know
where to draw that line.

You do not have a new species,

Not yet, but it's very close, in some dog breeds. It's highly
unlikely that a wolf would be able or willing to breed with a
Pekingese, or a Jack Russel terrier.

you have a dog that can no longer mate with
it's ancesor. Nor should it. Do you mate with your great grandmother?

Well, even if she were alive today, I wouldn't, due to societal rules
against incest. However wolves alive today aren't the "grandmother"
of dogs, they are their cousins. Similarly they are cousins of
foxes, jackals, and African wild dogs, and other canids. They are
even more distant cousins of cats, otters, and seals.


By reclassifying the dog into a new species
you are allowing that chain to be broken and go sideways, even
backwards, and thereby allowing evolution to appear to be true.

Classifying dogs into a new species recognizes the fact that they have
become reproductively isolated from their parent population.  There's
nothing about going 'sideways" or "backwards" about it.   Talking
about evolution having a particular direction is a deep
misunderstanding of the process.

This is incorrect.


Sorry, but it's quite correct.

Because by reclassifying the dog, you are allowing it to
appear that any further divergence is not associated with the wolf.

Any "further divergence" is not associated with wolves, but with
dogs. Dogs are mostly separate populations from wolves today, even
though their ancestors were wolves. The point is that wolves today
are also separte from their ancestors. They simply haven't had the
selection pressure that the population of dogs have undergone.
Dogs have been artificially selected by humans for specific traits.
Wolves, by and large have not, so they retain their "wild" traits.


Dogs came from the wolf.

Of course, but they've changed since that time. That change is a form
of evolution.

Any further microevolution from the dog will remain
a descendent of the wolf because the dog cannot breed with another species
such as a cat to add new DNA into the original wolf line that the dog
possesses.

No one claims that dogs will breed with cats, and it's unnessary for
them to breed with cats to "add new DNA". New DNA is produced by
mutations in the population of dogs. That's why wolves and dogs
are quite different in morphology and behavior, even though they are
closely related.

Evolution does not require one organism to turn into another already
existing organism. It doesn't require that one population breed with
another distantly related species. All that is required is for
mutations to continually be fixed into the new population.

If you truly wanted a new species, THAT is how to get one. Figure out a way
to mix a dog and a cat.

No, a new species is produced when a diverging population is no longer
able to breed with it's parent population. Mating dogs and cats
does not produce a new species. In fact mating dogs and cats won't
produce any offspring at all. That's because the population that we
call "dogs" is too far diverged from the population that we call
"cats" today. About 30 million years ago, according to the genetic
evidence, the two populations shared a common ancestor.


If you say the dog is no longer a descendent of the wolf, then you can allow
the dog to give rise to a new species as well.

Recognizing that dogs will become a new species does not say they are
"no longer descended" from wolves. It says they are now a
reproductively isolated population, which do not normally interbreed
with wild wolves today. Humans, for example did not suddenly become
"not descended from apes" when they became their own separate
population.

Where does it stop?

It doesn't, until all life become extinct. There aren't any known
barriers to speciation.

Every
species on the planet can be re-cataloged as another new species after a
divergence with reproductive isolation that way.

Correct, as long as that species produces a population which cannot
interbreed with the parent population. In actual practice, most
species become extinct before they do that.

OR WORSE, someone can pick
and choose what they /think/ is a new species that way.

As long as they can show that the new population is reproductively
isolated, why not? Scientific journals are full of arguments over
whether a new population should be considered a new species, or not.
Taxonomists are generally either "lumpers' who argue that populations
belong to a single species, or "splitters" who believe that each
population should be considered it's own species.


But reproductive
isolation has not changed the fact that the wolf is the original descendent
of the dog and any creature that may rise from the dog.

No one claims that being a new species causes a population to become
something other than a descendant of it's parent species. Where do
you get the idea that it does?

That means that the
dog and any sub species that followed the dog is not a new species but a
different form of the original species. This is orderly and not random.

The problem is, that if anyone followed your system, there'd only be
one "species" on Earth. All life is a descendant of an orginal
population of an organism.

Biologists tend to recognize that species are growing and changing
populations, and that defining exactly when a population becomes a new
species is almost impossible. Species are not an orderly concept,
they are messy, much like life itself.


The entire universe shows order.

Some of the universe shows order. Much of it is chaotic.

Why would you think there would be no order
regarding evolution of life?

There is order regulating evolution, but it's the order of natural
laws. Natural laws don't have to match human expectations, and human
desire to see patterns.



it is THAT simple.

Unfortunately for you, life is much more complicated than that.

DJT

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