Bull Trout

Skwala wrote:

"rw" wrote in message
. ..
On 2004-02-05 08:09:51 -0700, "Thomas Gnauck" said:


They are two different species. The Dolly Varden is Salvelinus malma malma
and the Bull Trout is Salvelinus confluentus. This web site gives a
description of the differences:

Personally, as a layman, I can't really believe that taxonomy and speciation
are actually the same thing.

Did reclassifiing Salmo Gairdneri to Oncorhynchus mykiss reveal any new
truth about the rainbow?

You mean other than recognizing that it is more closely related to
Pacific salmon than to Atlantic salmon and that previous theories of how
it evolved were erroneous?

JR

Chas Wade wrote:

The Deschutes in Oregon is the home of the Redsides rainbow. It's
actually a rainbow/cutthroat cross that developed long ago when there
was a landslide that blocked upstream migration on the Columbia.

What evidence is there for this?

JR

Bob Weinberger wrote:

The Deschutes is famous for both Redsides and Steelhead. To my knowledge,
they are genetically indistinguishable.

I believe that's right. In general, resident rainbows are genetically
virtually identical to the steelhead in the same subwatershed and
genetically relatively different from rainbows/steelhead in other
watersheds. Not surprisingly, and again in general, genetic differences
between O. mykiss of either form east of the Cascade crest and O. mykiss
of either form west the crest are considerably greater than differences
between O. mykiss from one watershed to the next on the same side of the
crest.

Here's an interesting paper I posted a couple of years ago here, I
think, on genetic differences between various steelhead ESUs:

http://www.nwfsc.noaa.gov/publicatio...7/genetics.htm

Some Steelhead fingerlings never go
to sea and become resident Redsides and some Redsides go to sea and become
Steelhead. Several other rivers in the vicinity have the same situation.
The reason some rainbows exhibit anadromy, while others in the same system
do not, is a mystery to fish biologists.

There's some thinking--but no experimental evidence as far as I
know--that environmental factors influencing levels of competition for
food may play a key role. Greater than normal levels of competition for
food may induce somewhat higher rates of smoltification in offspring of
resident fish; lower levels than normal may result in more "anadromous"
fingerlings staying resident.

You getting to the Owyhee much?

JR

rw wrote in message ...
On 2004-02-06 15:21:48 -0700, (Jonathan Cook) said:

Lions and tigers have been bred and produced fertile offspring. Would you
call them one species?

Assuming fertile offspring is the norm between the two, yes.

If biologists were consistent in applying their own "rules" about
what constitutes a species, such as physical, geographic, or
behavioral isolation, then we ought to have a multitude of human
species, and a multitude of dog species, and plenty of other
examples. The current use of these rules is "soft science" and
it bothers me.

Lately it seems like the readiness to declare new species is also
founded on political reasons -- mainly to bring the endangered
species act into play and "preserve" the environment. In NM we have
the Rio Grande silvery minnow, a very endangered species. Well we
had a state biologist talk at our FF club and I learned that there's
a Pecos river silvery minnow that is not endangered and that can
only be distinguished from the RG minnow by a delicate autopsy
and inspection of the vertabrae at the base of the skull. When I
asked why it is considered a different species, I was basically
talked down to as if I didn't understand science and no
reasonable person would even think that (they *are* geographically
isolated and have been for a while).

Jon.

On 2004-02-07 08:26:36 -0700, (Jonathan Cook) said:

rw wrote in message
...
On 2004-02-06 15:21:48 -0700, (Jonathan Cook) said:

Lions and tigers have been bred and produced fertile offspring. Would
you
call them one species?

Assuming fertile offspring is the norm between the two, yes.

Fortunately, the definition of "species" isn't left to armchair
taxonomists.

As Darwin wrote to Joseph Hooker: "How painfully true is your remark that
no one has hardly the right to examine the question of species who has not
minutely described many."

-----------------------------------------------------
Cut "to the chase" for my email address.

Skwala wrote:

Did reclassifiing Salmo Gairdneri to Oncorhynchus mykiss reveal any new
truth about the rainbow?


Skwala


The reclassification occurred because new truths were revealed about the
Rainbow. It was placed in the genus Oncorhynchus because it was found to
be more closely related to Pacific Salmon than brown trout or Atlantic
salmon.

Classification systems are designed to reflect similarities among
species. A "good" classification system will reflect evolutionary
relationships among species. As new information comes to light,
especially now with molecular taxonomic tools, classifications based on
superficial resemblances become replaced with systems based on genetic
similarity. That is waht happened with rainbows.

Tim Lysyk

"JR" wrote in message ...
Skwala wrote:

"rw" wrote in message
. ..
On 2004-02-05 08:09:51 -0700, "Thomas Gnauck"
said:


You mean other than recognizing that it is more closely related to
Pacific salmon than to Atlantic salmon and that previous theories of how
it evolved were erroneous?

JR

I haven't read anything on this in years, so correct me if I'm wrong, but, I
thought the desicion to reclassify was based more on logic, than
physological evidence.

The logic based on assumptions of what we know about the post ice age
history of the pacific region.

Again, I haven't studied the question in any detail, so I may be assuming
too much myself.

Skwala

Jonathan Cook wrote:

rw wrote in message ...

On 2004-02-06 15:21:48 -0700, (Jonathan Cook) said:


Lions and tigers have been bred and produced fertile offspring. Would you
call them one species?


Assuming fertile offspring is the norm between the two, yes.

If biologists were consistent in applying their own "rules" about
what constitutes a species, such as physical, geographic, or
behavioral isolation, then we ought to have a multitude of human
species, and a multitude of dog species, and plenty of other
examples. The current use of these rules is "soft science" and
it bothers me.

Lately it seems like the readiness to declare new species is also
founded on political reasons -- mainly to bring the endangered
species act into play and "preserve" the environment. In NM we have
the Rio Grande silvery minnow, a very endangered species. Well we
had a state biologist talk at our FF club and I learned that there's
a Pecos river silvery minnow that is not endangered and that can
only be distinguished from the RG minnow by a delicate autopsy
and inspection of the vertabrae at the base of the skull. When I
asked why it is considered a different species, I was basically
talked down to as if I didn't understand science and no
reasonable person would even think that (they *are* geographically
isolated and have been for a while).


I used to accept your definition because it seemed to make the most
sense and seemed concrete and absolute. However, through reading and
thinking about it, I've come to the conclusion that it is as arbitrary
as any other definition. There are problems with any definition of a
species. Any definition of "species" is just an attempt to choose a
specific point on a continuum.

Although your definition may seem concrete on the surface, it too is
arbitrary and depends on your definition of "bred" and "fertile" and
when man's intervention is thrown into the mix, things get even more
complex.

With your definition, some of the choices that need to be made include:


Animals that will occasionally breed naturally in the wild

Animals that would breed naturally in the wild but never come into
contact because of physical barriers

Animals that could breed naturally in the wild but don't because of
behavioral differences

Animals that will breed only when confined together in captivity who in
the wild have contact but choose not to interact

Animals that will breed in captivity only when treated with hormones or
other types of manipulation

Animals that won't breed but will have fertile offspring through simple
artificial insemination

Animals that won't breed but will have fertile offspring through
artificial insemination with physical changes made such as a change in PH

Then we get into genetic manipulation

As man makes more technological advances, more and more levels will be
introduced that will need to be considered.

How the definition is to be used adds even more complexity. Is it being
used to describe the evolutionary process, explain genetic differences,
for political reason, etc.

Willi

On 2004-02-07 10:42:13 -0700, Willi said:

I used to accept your definition because it seemed to make the most sense
and seemed concrete and absolute. However, through reading and thinking
about it, I've come to the conclusion that it is as arbitrary as any other
definition. There are problems with any definition of a species. Any
definition of "species" is just an attempt to choose a specific point on a
continuum.

----------------------------------------------------

I both agree and don't agree, Willi. Species are the principal units of
evolution. While there's been a long history of debate about the definition
(the "species problem" in biology), few if any serious biologists would
deny that species are objective, concrete phenomena. This greatly
constrains the possible definitions of "species."

There is a spectrum of opinion. On the far right, so to speak, are people
like Jon who insist on the most rigid and absolute definiton -- if two
organisms can produce fertile offspring then they belong to one species.
This leads to absurdities, like the lions and tigers example.

On the left are the nominalists who argue that "species" is an arbitrary,
man-made concept. That is, IMO, the looney deconstructionist wing, who
argue from a political agenda. I don't take them seriously.

The truth is in the middle. Species are "real," but pinning them down with
a simple definition is hard.

(Somewhere off in Cloud Cuckoo Land are those who claim that species are
the immutable creations of God and that evolution doesn't exist.)

-----------------------------------------------------
Cut "to the chase" for my email address.

"Willi" wrote in message
...


Jonathan Cook wrote:

rw wrote in message
...

On 2004-02-06 15:21:48 -0700, (Jonathan Cook) said:


Lions and tigers have been bred and produced fertile offspring. Would
you
call them one species?


Assuming fertile offspring is the norm between the two, yes.

If biologists were consistent in applying their own "rules" about
what constitutes a species, such as physical, geographic, or
behavioral isolation, then we ought to have a multitude of human
species, and a multitude of dog species, and plenty of other
examples. The current use of these rules is "soft science" and
it bothers me.

Lately it seems like the readiness to declare new species is also
founded on political reasons -- mainly to bring the endangered
species act into play and "preserve" the environment. In NM we have
the Rio Grande silvery minnow, a very endangered species. Well we
had a state biologist talk at our FF club and I learned that there's
a Pecos river silvery minnow that is not endangered and that can
only be distinguished from the RG minnow by a delicate autopsy
and inspection of the vertabrae at the base of the skull. When I
asked why it is considered a different species, I was basically
talked down to as if I didn't understand science and no
reasonable person would even think that (they *are* geographically
isolated and have been for a while).


I used to accept your definition because it seemed to make the most
sense and seemed concrete and absolute. However, through reading and
thinking about it, I've come to the conclusion that it is as arbitrary
as any other definition. There are problems with any definition of a
species. Any definition of "species" is just an attempt to choose a
specific point on a continuum.

Although your definition may seem concrete on the surface, it too is
arbitrary and depends on your definition of "bred" and "fertile" and
when man's intervention is thrown into the mix, things get even more
complex.

With your definition, some of the choices that need to be made include:


Animals that will occasionally breed naturally in the wild

Animals that would breed naturally in the wild but never come into
contact because of physical barriers

Animals that could breed naturally in the wild but don't because of
behavioral differences

Animals that will breed only when confined together in captivity who in
the wild have contact but choose not to interact

Animals that will breed in captivity only when treated with hormones or
other types of manipulation

Animals that won't breed but will have fertile offspring through simple
artificial insemination

Animals that won't breed but will have fertile offspring through
artificial insemination with physical changes made such as a change in PH

Then we get into genetic manipulation

As man makes more technological advances, more and more levels will be
introduced that will need to be considered.

How the definition is to be used adds even more complexity. Is it being
used to describe the evolutionary process, explain genetic differences,
for political reason, etc.

Plants......you forgot about plants. How about an apple trunk grafted onto
pear rootstock and later augmented with plum and cherry branches? (It's
doable.....they're all Rosaceae and graft relatively easily.)

And then, there is the rather knotty problem of asexual reproduction. Any
definition that depends on the successful mating of a pair of individuals
resulting in fertile offspring sort of leaves yeasts, for example, out in
limbo. If no two of the saccharomyces cavorting in my bread dough ever get
together to do the nasty, is every one of them a different species?

And what about bacteria that simply grab a chunk of DNA from some host and
make it their own? Looks to me like any one of them may actually be two or
more species based on genetic evidence.

Any recognized species of lichen IS two species, and of different kingdoms
at that.

Viruses. Viruses don't have ANY DNA of their own.

Species are a fiction. They can be very useful fictions, but the uses to
which they are put are not always noble or even justifiable.

The vast majority of species on the planet fail to conform nicely to the
traditionally accepted definition.

Wolfgang
mitochondria, anyone?