Similarities & Common Descent
david ford
If 2 organisms have similar body structures, then they obtained those
similar structures from a common ancestor-- the similarities in the
structures are attributable to common descent from a common ancestor
that had the original version of the structure(s) in question.
Randy Story
"david ford" <dfo...@gl.umbc.edu> wrote in message
news:b1c67abe.04010...@posting.google.com...
If two bridges have common structural similarities does that mean that they
have common anscentry or common design. I think common design.
Boikat
It depends on how detailed you get with the "similar body structures". The
flipper of a sea turtle and the flipper of a blue whale are similar, yet the
two did not inherit the flipper from a common ancestor.
Boikat
Lenny Flank
Show us how to test it. Let's take an example -------- humans and
chimps both have a broken vitamin C gene. Show us how to apply the
scientific method to your hypothesis "this broken gene is similar in
both species because of common design".
If you are like most creationists, you don't know what the scientific
method is. Let me help you out:
*ahem*
1. Observe some aspect of the universe.
OK, so we observe that humans and chimps share
unique genetic markers, including a broken vitamin C
gene.
2. Invent a tentative description, called a hypothesis,
that is consistent with what you have observed.
OK, your proposed hypothesis is "an intelligent
designer used a common design to produce both
chimps and humans, and that common design
included placing a broken vitamin C gene in both products."
3. Use the hypothesis to make predictions.
Here is your chance to shine. What
predictions can we make from your hypothesis. If an
Intelligent Designer used a common design to
produce both chimps and humans, then we would
also expect to see . . . . . . . . . . . .?
Fill in the blank.
And, to better help us test your hypothesis, it's most
useful to point out some negative predictions ---
things which, if found, would FALSIFY your
hypothesis and demonstrate conclusively that your
hypothesis is wrong. So, then --- if we find (fill in the
blank here), then the "common design"
hypothesis would have to be rejected.
4. Test those predictions by experiments or further
observations and modify the hypothesis in the light
of your results.
5. Repeat steps 3 and 4 until there are no
discrepancies between theory and experiment
and/or observation.
Well, we seem to be sort of stuck on step 3.
Help us out here. Give us some testible predictions
from your hypothesis. Tell us how to go about
testing them.
Or, would you rather than we just skip steps 3,4 and
5, and just take your religious word for it that your
hypothesis must be true. Is that, after all, what ID is
all about?
Take note here --- there are NO limits
imposed here on the nature of your predictions,
other than the simple ones indicated by steps 3,4
and 5 (whatever predictions you make must be
testible by experiments or further observations.) You
are entirely free to invoke whatever deities or
supernatural causes that you like, in whatever
number you like, so long as you follow along to steps
3,4 and 5 and tell us how we can test these deities
or causes using experiment or further observation.
Want to tell us that the Good Witch Glenda used her
magic non-naturalistic staff to POP these genetic
sequences into both chimps and humans? Fine ---
just tell us what experiment or observation we can
perform to test that. Want to tell us that God didn't
like humans very much and therefore decided to
design us with broken vitamin C genes? Hey, works
for me -- just as soon as you tell us what experiment
or observation we can perform to test it. Feel entirely
and totally free to use all the supernaturalistic
causes that you like. Just tell us what
experiment or observation we can perform to test
your predictions.
Let's throw methodological
materialism right out the window. Gone. Bye-bye.
Everything's fair game now. Ghosts, spirits,
demons, devils, cosmic enlightenment, elves, pixies,
magic star goats, whatever god-thing you like. Feel
free to include and invoke all of them. As many as
you need. Show us all how to apply the scientific
method to whatever non-naturalistic science you
choose to invoke in order to subject your hypothesis
"genetic similarities between chimps and humans
are the product of a common design" to the scientific
method.
===============================================
Lenny Flank
"There are no loose threads in the web of life"
Creation "Science" Debunked:
http://www.geocities.com/lflank
DebunkCreation Email list:
http://www.groups.yahoo.com/group/DebunkCreation
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
Lenny Flank
Er, I've not noticed any bridges screwing and reproducing little bridges
as descendents. Have you?
<sigh> No WONDER everyone thinks creationists are idiots.
gen2rev
wrote in <b1c67abe.04010...@posting.google.com>:
Nothing that I can see. Of course, it all depends on what you mean by
"similar" Are bat wings and bird wings similar? They certainly have
similar functions, but no one is going to claim that their common
ancestor had wings.
Vic Sagerquist
Bridges are inanimate, dumbfuck.
--
Vic Sagerquist
aa#2011
______________
The fool says in his heart, "There is no God".
The wise man announces it to the world.
Carl
But what if bridges self replicated? This of course, does not negate
common design. However, the problem arises when common design is
required to explain subtle and usually predictable non-essential
variations of design. Common descent explains both.
--
Creation Science: the bastard child of Scientism and Fundamentalism.
Woden
@posting.google.com:
I guess that means that birds, insects, bats, and pterodactyls all had a
common ancestor with wings.
--
Woden
"religion is a socio-political institution for the control of
people's thoughts, lives, and actions; based on
ancient myths and superstitions perpetrated through
generations of subtle yet pervasive brainwashing."
Matt Silberstein
(david ford):
Two organisms are not sufficient, that is why scientists look at
thousands of organisms. "Similarities" is an insufficient
specification, what similarities are we talking about. Again, if
we had a dozen organisms we could begin to discuss a tree. Not
all similarities come from descent, we would want to look at more
details. Of course many of these problems would be resolved if
David did not play games like this and we saw the passage in the
original context. In that case I suspect that many of the issues
would be resolved.
William Barwell
Everything?
Sometimes, body structure is the result of evolving to fit an given
enviroment.
Example, fish, dolphins and some aquatic dinosaurs had
similar bodies, evolved to be efficient in water.
Note sharks have no bones, yet are similar in shape to dolphines.
Far different evolutionary pathways. Yet similar shapes.
Eyes are useful, and have evolved at least five time sin differing
families. But the fact that crabs and grasshoppers have eyes does not
necessarily mean they evolved from a common ancestor that had eyes
similar to crabs or grasshoppers. They have eyes and crustaceans and
insects evolved seperately. Molluscs (squid and octopus) have complex
eyes, they did not evolve from a common ancestor with eyes that
gave us apes and squid with eyes.
--
Bush! Chimp or chump?
Cheerful Charlie
John Harshman
david ford wrote:
You already know what's wrong with it. What sort of rhetorical point are
you trying to make here?
We know that convergence is fairly common for individual
characteristics. What's quite rare is whole-organism convergence, such
that scientists are actually fooled about relationships, and this has
become reduced even more as a result of the vast expansion of the
available data coming from DNA sequences.
Your problem is that nobody actually makes the claim you discuss here.
It's a strawman that has nothing to do with actual inferences of common
descent made by real biologists. If you want to support a creationist
agenda, you will have to address the actual data and arguments.
Steven Carr
I wonder if David has the same number of eyes and heads as his
siblings, and if this could be attributable to their having a common
ancestor?
Steven Carr
ste...@bowness.demon.co.uk
http://www.bowness.demon.co.uk/
A Pagano
ford) wrote:
Pagano replies:
The consequent does not follow from the antecedent; that is, it is a
non sequitur. Unless additional premises are provided making the
logical connection between similar structures and lineal descent.
Modern secular evolutionary theory presupposes as an axiom (not a
scientifically tested theory) that similarity of structure is prima
facie evidence of a purely naturalistic lineal connection between the
two. But we already know from direct observation that similarity of
structure can be the result of a common design not necessity and
chance.
While common descent has been observed in a very limited sense no such
undemonstrated axiom of "similarity deductively implies lineal
connection" is required. It is this undemonstrated axiom which fills
the gap between the dinosaur forearm and avian wing, for example.
Regards,
T Pagano
gen2rev
wrote in <teo9vvg8pevm8p0l6...@4ax.com>:
[snip]
> While common descent has been observed in a very limited sense no such
> undemonstrated axiom of "similarity deductively implies lineal
> connection" is required. It is this undemonstrated axiom which fills
> the gap between the dinosaur forearm and avian wing, for example.
As I have pointed out to Pagano before, this is untrue. We have fossil
evidence demonstrating, and filling in, the transition "between the
dinosaur forearm and avian wing". I can outline the aforementioned
transition if Pagano desires.
> Regards,
> T Pagano
Nathan Baum
Bridges are not biological constructs. Significantly, bridges do not contain
any mechanism for self-replication.
A bridge is a phenotype of the genotype that is present within its human
designer(s). Evolution dictates common descent of genotypes, not
phenotypes. Most bridges are a modification of the design of previous
bridges, which is to say that modern bridge genotypes are evolved from old
bridge genotypes.
Pip R. Lagenta
ford) wrote:
Spiders have eight legs and octopuses have eight legs, therefore
spiders and octopuses have a common ancestor that had eight legs?
Uhhh, no.
Define your terms clearly, and try again.
內躬偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,
Pip R. Lagenta Pip R. Lagenta Pip R. Lagenta Pip R. Lagenta
�虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌`偕爻,虜,齯滌
-- Pip R. Lagenta
President for Life
International Organization Of People Named Pip R. Lagenta
(If your name is Pip R. Lagenta, ask about our dues!)
---
<http://home.comcast.net/~galentripp/pip.html>
(For Email: I'm at home, not work.)
Denis Loubet
"Randy Story" <rsto...@olypen.com> wrote in message
news:vv9bult...@corp.supernews.com...
I would think the structural features of the bridge design were arrived at
by an evolutionary process that involved keeping those features that are
found to support bridges, and eliminating those features that did not.
In other words, trial and error.
--
Denis Loubet
dlo...@io.com
http://www.io.com/~dloubet
Elmer Bataitis
> While common descent has been observed in a very limited sense.....
Bwhahahaha!Please name any other kind of descent for us Tony ;-)
***************************************************************
Elmer Bataitis “Hot dog! Smooch city here I come!”
Planetech Services -Hobbes
585-442-2884
"...proudly wearing and displaying, as a badge of honor, the
straight jacket of conventional thought."
***************************************************************
us...@example.com
Well, taken out of context, I suppose what's wrong is that the claim
doesn't define similar body structures. What is the context of the
claim?
Frank Reichenbacher
The spine of a euphorbia and the spine of a cactus are similar, yet science
believes the structures have quite different origins and do not indicate a
common ancestry.
The flipper of a whale and the hand of a human are dissimilar, yet they
share all the same bones and are derived from the same structures.
Frank
Frank Reichenbacher
"A Pagano" <inv...@address.none> wrote in message
news:teo9vvg8pevm8p0l6...@4ax.com...
> On Thu, 1 Jan 2004 23:19:00 +0000 (UTC), dfo...@gl.umbc.edu (david
> ford) wrote:
>
> >What, if anything, is wrong with the following claim?:
> >
> >If 2 organisms have similar body structures, then they obtained those
> >similar structures from a common ancestor-- the similarities in the
> >structures are attributable to common descent from a common ancestor
> >that had the original version of the structure(s) in question.
>
>
> Pagano replies:
> The consequent does not follow from the antecedent; that is, it is a
> non sequitur. Unless additional premises are provided making the
> logical connection between similar structures and lineal descent.
>
> Modern secular evolutionary theory presupposes as an axiom (not a
> scientifically tested theory) that similarity of structure is prima
> facie evidence of a purely naturalistic lineal connection between the
> two.
The spine of a euphorbia and the spine of a cactus are similar, yet science
believes the structures have quite different origins and do not indicate a
common ancestry.
The flipper of a whale and the hand of a human are dissimilar, yet they
share all the same bones and are derived from the same structures.
You had a very tidy strawman there, Tony, but it fell apart in the face of
reality.
Frank
Roadrunner
"Carl" <no_...@all.fu> wrote in message news:3FF4B7C3...@all.fu...
Bridges are not living material as we know it is it? Would bridges evolve
in better bridges without a creator changing it's design. Dont think so.
Roadrunner
Not necessarily wrong however the occuring can also be explained by a common
designer. That means you have to assume that the above is correct, you
can't state it being a fact though.
"Rev Dr" Lenny Flank
> Modern secular evolutionary theory
What is your nonsecular alternative, Tony. You keep yammering about it,
but for some odd reason you never want to show it to anybody.
Why is that.
> While common descent has been observed in a very limited sense no such
> undemonstrated axiom of "similarity deductively implies lineal
> connection" is required. It is this undemonstrated axiom which fills
> the gap between the dinosaur forearm and avian wing, for example.
>
I see.
Why, again, does DNA paternity testing work . . . . . . . . ?
Steven J.
"A Pagano" <inv...@address.none> wrote in message
news:teo9vvg8pevm8p0l6...@4ax.com...
> ford) wrote:
>
> >What, if anything, is wrong with the following claim?:
> >
> >If 2 organisms have similar body structures, then they obtained those
> >similar structures from a common ancestor-- the similarities in the
> >structures are attributable to common descent from a common ancestor
> >that had the original version of the structure(s) in question.
>
> Pagano replies:
> The consequent does not follow from the antecedent; that is, it is a
> non sequitur. Unless additional premises are provided making the
> logical connection between similar structures and lineal descent.
>
Rather than "similar body structures," he should have "homologies," defined
as structures with detailed similarities which are not required either by
intrinsic constraints of biological organisms or by the demands of the
structure's function. As Matt Silberstein notes, you can't just compare two
organisms, you need large numbers of organisms to get some sense of how much
similarity is required by the mere fact of being biological organisms, or by
occupying a given niche, and how much disparity in structure is possible.
>
> Modern secular evolutionary theory presupposes as an axiom (not a
> scientifically tested theory) that similarity of structure is prima
> facie evidence of a purely naturalistic lineal connection between the
> two. But we already know from direct observation that similarity of
> structure can be the result of a common design not necessity and
> chance.
>
(centuries of selective breeding, for one thing) to tell us that shared
ancestry is a very frequent cause of homology. The similarities of one
pigeon, or cow, or dog, to another are pretty well established to be the res
ult of common descent; this explains both the general homologies within the
species and the homologies by which one breed is distinguished from another.
In some cases, where human experimentation has resulted in speciation,
homologies between two species can be very strongly inferred to result from
common descent.
We do know, of course, that similarities of structure can result from shared
design. In that case, though, we tend to expect actual *common* design --
identical design for identical purposes. The homologies among hummingbird,
condor, swallow and penguin wings could be explained by common design -- but
that would leave unexplained their lack of homology (as wings; they are
homologous as forelimbs) with bat and pterosaur wings. It's hard to
explain, on the assumption of common design, the diversity of structure (and
its arrangement in a nested hierarchy) of enzymes like cytochrome-c.
Note that homologous structures that serve distinct purposes (when alternate
designs are known to be possible, because they actually exist) are
especially hard to explain on the basis of common design, and more easily
explicable on the basis of common descent with modification. Some of the
most compelling cases of this exist on the molecular level -- shared
pseudogenes (which, whatever function they might serve, don't serve the
functions of the genes to which they are homologous) and shared endogenous
retroviruses.
Note that creationists readily accept nested hierarchies of homology as
evidence for common descent, within whatever the particular creationist
regards as the limits of "created kinds." Thus the "dog kind" (whether the
species _Canis lupus_, or the genus _Canis_, or the whole family Canidae) is
recognized on the basis of these homologies -- detailed similarities which
members of the "dog kind" don't have to share with each other to function in
their niches, but share with each other anyway. The difficulty is that such
homologies are shared across taxa far higher than creationists are willing
to accept as "kinds."
>
> While common descent has been observed in a very limited sense no such
> undemonstrated axiom of "similarity deductively implies lineal
> connection" is required. It is this undemonstrated axiom which fills
> the gap between the dinosaur forearm and avian wing, for example.
>
Every paternity test, of course -- indeed, every DNA test used for either
civil or criminal legal purposes -- rests on the assumption (based on quite
a bit of evidence) that homology at the genetic level is pretty strong
(though not deductively certain) evidence for shared ancestry. One could,
of course, construct a deductive "proof" for this "axiom" -- but it would be
(like any other deductive proof) no more certain than its premises. The
consilience of myriad streams of induction is, ultimately, a stronger
(though not deductively certain) basis for the "axiom."
Morphologically, the gap between the dinosaur forelimb and avian wing is
rather exhaustively filled, actually. _Compsognathus_, _Archaeopteryx_,
_Confuciusornis_, and hence to modern birds shows how incremental
modifications of the theropod limb yield the avian wing. One could trace
theropod limbs further back, showing the derivation of the avian wing from
the "lobe-fins" of crossopterygian fish. Of course, no one actually saw
this evolution happen; all that has been observed is reproduction, mutation,
and natural selection, and the pattern of homologies explicable by common
descent more readily than by design.
>
> Regards,
> T Pagano
>
-- Steven J.
Penny Nickels
"William Barwell" <wbar...@mungged.mylinuxisp.com> wrote in message
news:3ff4b9fe$0$132$811e...@news.mylinuxisp.com...
are from a common ancestor, by the same token the eyes of shrimp,
lobsters, squid, crabs etc must have inhirited their eyes from a common
ancestor. The same must be true of grasshoppers, beetles, roaches
etc. They must have had a common ancestor.
Dr. DuFonet
"Lenny Flank" <lflank...@ij.net> wrote in message
news:3ff4b...@corp.newsgroups.com...
> Randy Story wrote:
>
> > "david ford" <dfo...@gl.umbc.edu> wrote in message
> > news:b1c67abe.04010...@posting.google.com...
> >
> >>What, if anything, is wrong with the following claim?:
> >>
> >>If 2 organisms have similar body structures, then they obtained those
> >>similar structures from a common ancestor-- the similarities in the
> >>structures are attributable to common descent from a common ancestor
> >>that had the original version of the structure(s) in question.
> >
> >
> >
> > If two bridges have common structural similarities does that mean that
they
> > have common anscentry or common design. I think common design.
>
>
>
>
> Er, I've not noticed any bridges screwing and reproducing little bridges
> as descendents. Have you?
>
--
Freedom of thought entails no "Intellectual Property".
Penny Nickels
"Woden" <wo...@charter.net> wrote in message
news:Xns9463C56A96w...@216.168.3.44...
> What, if anything, is wrong with the following claim?:
>
> If 2 organisms have similar body structures, then they obtained those
> similar structures from a common ancestor-- the similarities in the
> structures are attributable to common descent from a common ancestor
> that had the original version of the structure(s) in question.
>
I guess that means that birds, insects, bats, and pterodactyls all had a
common ancestor with wings.
Penny writes:
Of course, this is direct evidence of common descent. You cannot on
one hand argue that similarity denotes common descent, but on the
other argue that similarities do not denote common ancestry. To do
so would be inconsistent. You cannot have it both ways, that would
be irrational. Similarities are in fact empirical evidence of common
ancestry.
Similiarities in dogs, wolves, foxes and coyotes is strong evidence
that they all descended from a common ancestor.
Similarities in the design of buildings, bridges does not indicate a
common designer, these objects are _known_ to be man made and
by different cultures and at different times.
--
Carl
I see you aren't familiar with genetic algorithms.
Here is a textbook, and damn it, it even has a bridge on the cover
http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471999024.html
--
Creation Science: the bastard child of Scientism and Fundamentalism.
Scientism: science will provide the answer to everything
Fundamentalism: we already know the answer
John Popelish
>
> What, if anything, is wrong with the following claim?:
>
> If 2 organisms have similar body structures, then they obtained those
> similar structures from a common ancestor-- the similarities in the
> structures are attributable to common descent from a common ancestor
> that had the original version of the structure(s) in question.
Such similarities certainly suggest that common ancestry might be an
explanation, but many useful structures have evolved in parallel in
different lines, so common ancestry is not a certainty. Other
evidence is needed to make a reasonable decision. The more detailed
and numerous the similarities, the stronger the support for the common
ancestry explanation.
--
John Popelish
Penny Nickels
"gen2rev" <gen...@crosswinds.net> wrote in message
news:24d9vv4tmcg4nvv29...@4ax.com...
On Thu, 1 Jan 2004 23:19:00 +0000 (UTC), dfo...@gl.umbc.edu (david ford)
wrote in <b1c67abe.04010...@posting.google.com>:
> What, if anything, is wrong with the following claim?:
>
> If 2 organisms have similar body structures, then they obtained those
> similar structures from a common ancestor-- the similarities in the
> structures are attributable to common descent from a common ancestor
> that had the original version of the structure(s) in question.
gen2rev wrote:
Nothing that I can see. Of course, it all depends on what you mean by
"similar" Are bat wings and bird wings similar? They certainly have
similar functions, but no one is going to claim that their common
ancestor had wings.
Penny writes:
Since similar structure is evidence of common descent from a
common ancestor, one must conclude that the wings of a bat
a bird and the flying reptiles which share common aerodynamic
prosperities must have a common ancestor from which they
descended. A flying reptile, no doubt an ancestor of the pterosaur
must also be the ancestor of both bats and birds.
Steven J.
"Penny Nickels" <5ce...@bellsouth.net> wrote in message
news:M96Jb.3894$wW5....@bignews6.bellsouth.net...
of function -- and whether the degree of similarity is "required" is
determined in large part by the study of disparity of structure among
organisms), when arranged in the nested hierarchy which is expected as a
result of common descent with modification (e.g. the nested hierarchy of
Indo-German languages) is evidence of common descent from a common ancestor.
Similarity of structure can be explained as convergence on a similar
solution to similar problems. There are numerous examples in nature.
The similarities of bat and bird (and pterosaur) wings are required for
flight. Actual homologies are closer between bats and a host of nonflying
mammals, while actual homologies are greater between birds and crocodilians
(or even birds and lizards and snakes) than between birds and mammals. This
is rather strong evidence (supplemented by the fossil record) that the last
common ancestor of birds and bats was flightless. So, for that matter, was
the more recent common ancestor of birds and pterosaurs, although both were
archosaurs.
>
-- Steven J.
Steven J.
out by human engineers) includes the possibility of purposeful redesign and
copying of design from many different sources, they, like many human
artifacts, are copied to some extent from previous exemplars. In that
sense, human artifacts *can* evolve, although they rarely do so in ways that
produce consistent nested hierarchies. One can distinguish between, e.g.
European and Chinese landscape painting, because while individual styles
differ, and both must be similar in depicting landscapes, there are cultural
idiosyncrasies in each -- and these are copied from previous works and
painters in the two cultures. The same holds for architecture and other
cultural artifacts of different cultures.
Note that it is not "similarity" per se that is evidence of common ancestry,
or even of common design. It is *homologies* (detailed similarities not
required by similarity of function or purpose), arranged in a consistent
nested hierarchy. Absent this aspect of homology, similarity may show
merely that designs have to be similar in order to serve similar functions;
it need show neither common descent nor common design (since independent
designers may hit on the same solution to a problem, if they face the same
problem and it has one obvious solution). Absent the consistent nested
hierarchy (and other aspects of life like different designs for the same
function, and vestigial structures), homology might indeed suggest common
design, not common descent.
-- Steven J.
>
> --
>
>
us...@example.com
>Since similar structure is evidence of common descent from a
>common ancestor, one must conclude that the wings of a bat
>a bird and the flying reptiles which share common aerodynamic
>prosperities must have a common ancestor from which they
>descended. A flying reptile, no doubt an ancestor of the pterosaur
>must also be the ancestor of both bats and birds.
Hmmm... similar function but not similar structure. If you look at the
wings of bats and birds, you'll see that they're built quite differently
from each other. Forget the feathers and fur for a moment, and just look
at the bones.
mb
>
> > "david ford" <dfo...@gl.umbc.edu> wrote in message
> > news:b1c67abe.04010...@posting.google.com...
> >
> >>
> >>If 2 organisms have similar body structures, then they obtained those
> >>similar structures from a common ancestor-- the similarities in the
> >>structures are attributable to common descent from a common ancestor
> >>that had the original version of the structure(s) in question.
> >
> >
> >
they
> > have common anscentry or common design. I think common design.
>
>
>
>
> as descendents. Have you?
>
WHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO.......
mb
"Vic Sagerquist" <add...@withheld.com> wrote in message
news:Xns9463A42...@204.127.199.17...
> One day in alt.atheism, Also Sprach Randy Story:
>
> >
> > "david ford" <dfo...@gl.umbc.edu> wrote in message
> > news:b1c67abe.04010...@posting.google.com...
> >> What, if anything, is wrong with the following claim?:
> >>
> >> If 2 organisms have similar body structures, then they obtained those
> >> similar structures from a common ancestor-- the similarities in the
> >> structures are attributable to common descent from a common ancestor
> >> that had the original version of the structure(s) in question.
> >
> >
> > If two bridges have common structural similarities does that mean that
> > they have common anscentry or common design. I think common design.
> >
>
>
>
.......OOOOOOOOOOOOOOOOOOOOOOSH ;-)
MarkA
> What, if anything, is wrong with the following claim?:
>
> If 2 organisms have similar body structures, then they obtained those
> similar structures from a common ancestor-- the similarities in the
> structures are attributable to common descent from a common ancestor
> that had the original version of the structure(s) in question.
Nothing wrong, as long as you don't try to apply it to people. When you
do that, you are going to inflame some people's "special act of creation"
reflex. Their entire worldview is absolutely dependant on the notion that
man is fundamentally different from other animals. If we "evolved" from
pre-human hominids, that distinction doesn't hold, and their theology
comes crashing down.
The obvious solution is to do what theists have ALWAYS done when the
physical evidence contradicts religious doctrine: persecute the scientist.
Fortunately for all of humankind (including, ironically enough, the
Creationists themselves), society has evolved to the point that theocrats
no longer have absolute authority over everyone's life (unless, of course,
you live in some of the few remaining theocracies, such as are found in
the Middle East). Therefore, they have to content themselves by trying to
rationalize how the evidence in favor of evolution *might be* false, and
further rationalize how weakening the theory of evolution indirectly
strengthens the "theory" that "Goddidit-all-by-magic", which is about as
antithetical to science as anything could possibly be.
--
MarkA
(still caught in the maze of twisty little passages, all different)
TomS
<uce9vvgfrod00r8vk...@4ax.com>, Matt Silberstein stated..."
>
>In talk.origins I read this message from dfo...@gl.umbc.edu
>(david ford):
>
>>What, if anything, is wrong with the following claim?:
>>
>>If 2 organisms have similar body structures, then they obtained those
>>similar structures from a common ancestor-- the similarities in the
>>structures are attributable to common descent from a common ancestor
>>that had the original version of the structure(s) in question.
>
>thousands of organisms. "Similarities" is an insufficient
>specification, what similarities are we talking about. Again, if
>we had a dozen organisms we could begin to discuss a tree. Not
>all similarities come from descent, we would want to look at more
>details. Of course many of these problems would be resolved if
>David did not play games like this and we saw the passage in the
>original context. In that case I suspect that many of the issues
>would be resolved.
>
I have two comments.
First of all, Matt is pointing out something which I haven't noticed
in many of the other responses.
It is *not* enough to note similarity of structures between two
bodily forms.
What we have, in the world of life on earth, is a *nested
hierarchy* of structures. Which points to a "tree" of relationships.
This is what leads us to the idea of a "common ancestry" and
"descent with modification". But not merely this ...
Along with a *mechanism* for descent with modification, which is
non-directed ("random") variations and natural selection.
This combination is what made the Darwin-Wallace contribution
so significant in 19th century biology. People were quite familiar
with the similarity of structures among living things.
Some combination of:
* Nested hierarchy of features
* Non-directed variation in descent
* Selection
is also known in the study of languages (which leads to the hypothesis,
for example, of common ancestry of a great many languages known as
"Indo-European"), and the study of manuscript traditions (which leads
to various hypotheses about reconstructing original texts).
*On a related point* ...
I have this question for people who feel uncomfortable with the
idea of common ancestry, but would prefer "common design":
Why should I feel better about the idea that some "intelligent
designers", or whoever or whatever are responsible for my body's
form ...
Why should I feel better about the idea that they had a common
purpose in designing my body to be so very much like the body of
chimps and other apes?
Why should I feel better about that idea, than about the idea
that my body shares some physical common ancestry with that of chimps?
If the persons (or things) responsible for my body have made my
body with a similar purpose in mind, a similar purpose to the design
that they put into the bodies of chimps (and other apes, other
mammals, other vertebrates, and, indeed, all other living things) ...
What am I supposed to do with this information about the purposes
that they have built into my body? The aims of the design that they
had in mind when designing the human body-type? Does this tell me
that they intended me to behave like chimps and other apes? Does
this tell me that my body is made to act like a chimp's body? Am
I frustrating the goals of these designers, if I don't "act like an
ape"?
You see, I don't see myself as having any obligation to "act like
my ancestors". If my great-grandfather was a horse thief; or my
ancestors back, not too many generations, illiterate peasants who
never took a bath; or my more distant ancestors several centuries BC
were pagan tree-worhsippers or cannibals -- that doesn't tell me
anything at all about what my behavior should be like today. Likewise,
if my ancestors back a few million years ago were more like apes,
that doesn't bother me.
"Ancestry" does not obligate me, not in a way that "purposeful
design" might.
gen2rev
<5ce...@bellsouth.net> wrote in
<M96Jb.3894$wW5....@bignews6.bellsouth.net>:
Actually, the wings of birds, pterosaurs, and bats are quite different
from each other and don't indicate a common ancestor that could fly.
Birds wings incorporate the 1st, 2nd, and 3rd digits, and there's a lot
of fusion of bones to form a new bone called the carpometacarpus.
Pterosaur wings are composed of a membrane of skin between an extremely
enlarged 4th digit and the legs.
Bat wings are made up of membranes of skin between the 2nd, 3rd, 4th,
and 5th digits and the legs.
More info can be found at
http://www.ucmp.berkeley.edu/vertebrates/flight/converge.html
Dave Oldridge
> What, if anything, is wrong with the following claim?:
>
> If 2 organisms have similar body structures, then they obtained those
> similar structures from a common ancestor-- the similarities in the
> structures are attributable to common descent from a common ancestor
> that had the original version of the structure(s) in question.
It's entirely possible that the similarities in question are obtained by
separate means. For example the eyes of cephalopods are evolved from the
primitive eyes of molluscs like those of snails. The eyes of vertebrates
are evolved from the primitive eyes of very rudimentary chordates. Both
eyes have some very similar structures, including eyeballs, lenses,
retina, etc. But there are also differences that reveal their different
origins. For example, the cephalopod eye has the retina in front of the
optic nerves that connect it to the brain. The vertebrate eye has it
behind and has a blind spot where the nerve bundle goes through the
retina. Too see the blind spot, close your right eye. Hold your right
hand with the forefinger up and hold your left hand with the forefinger
up right next to it. Then, focusing with the open left eye on the right
forefinger, move the left hand off to the left. The finger will vanish.
--
Dave Oldridge
ICQ 1800667
Paradoxically, most real events are highly improbable.
robpar
<rsto...@olypen.com> wrote:
>
>"david ford" <dfo...@gl.umbc.edu> wrote in message
>news:b1c67abe.04010...@posting.google.com...
>> What, if anything, is wrong with the following claim?:
>>
>> If 2 organisms have similar body structures, then they obtained those
>> similar structures from a common ancestor-- the similarities in the
>> structures are attributable to common descent from a common ancestor
>> that had the original version of the structure(s) in question.
>
>
>If two bridges have common structural similarities does that mean that they
>have common anscentry or common design. I think common design.
>
How about there are limits on what will work, and what works is what
is used. In evolution only what works will continue by being passed
on. So common design is limited to what works, and for the most part
works well.
>
Matt Silberstein
<peg...@privat.utfors.se>:
Please tell me how to distinguish between bridges
self-replicating and bridges being alive?
>Dont think so.
Then start thinking. If bridges self-replicated and, for example,
the longer bridges tended to survive to self-replicate, we would
tend to see longer bridges over time. If you disagree explain
why.
Bigdakine
>From: "tre...@sirius.com.no.more" us...@example.com
>Date: 1/1/04 5:10 PM Hawaiian Standard Time
>Message-id: <6bo9vv8n07918f3t7...@news.supernews.com>
Of course Ford, with his scholastic prowess, must know that at one time limpets
and barnacles were considered the same basic type of beastie, mollusk.
Until Chuck Darwin came along.
When Ford understands Darwin's argument, he'll perhaps understand why his is
nonsensical.
Stuart
Dr. Stuart A. Weinstein
Ewa Beach Institute of Tectonics
"To err is human, but to really foul things up
requires a creationist"
mel turner
[A Pagano] wrote...>ford) wrote:
[blather snipped]
>It is this undemonstrated axiom which fills
>the gap between the dinosaur forearm and avian wing, for example.
There's no such gap. The intermediate fossils are well-known.
cheers
Frank J
> >
> > If 2 organisms have similar body structures, then they obtained those
> > similar structures from a common ancestor-- the similarities in the
> > structures are attributable to common descent from a common ancestor
> > that had the original version of the structure(s) in question.
>
>
> have common anscentry or common design. I think common design.
And how do you think that "common design" is actuated in biology other
than by descent with modification?
Frank J
> "david ford" <dfo...@gl.umbc.edu> wrote in message
> news:b1c67abe.04010...@posting.google.com...
> > What, if anything, is wrong with the following claim?:
> >
> > If 2 organisms have similar body structures, then they obtained those
> > similar structures from a common ancestor-- the similarities in the
> > structures are attributable to common descent from a common ancestor
> > that had the original version of the structure(s) in question.
>
> Not necessarily wrong however the occuring can also be explained by a common
> designer.
Like I said several times before: unless you provide an alternate
means by which that "common design" was actuated (and you haven't, but
neither has anyone else, so don't feel bad), descent with modification
is it.
Note the discussion on homology v. homoplasy, though. Evolution
doesn't say that the relatedness of a particular structure is
necessarily by direct descent from a common ancestor. But unlike
anti-evolutionists, who deliberately take such anomalies out of
context to promote incredulity, mainstream science searches for
additional explanations.
> That means you have to assume that the above is correct, you
> can't state it being a fact though.
Then call it a "well-supported, falsifiable, but unfalsified,
conclusion"
instead of a "fact." The favorite implied alternative of
pseudoscientific anti-evolutionists, which is "independent
abiogenesis," however, remains a "thoroughly unsupported conjecture,"
whose promoters have given up trying to verify. So they revert to
hopelessly ambiguous phrases like "common design."
Frank J
> On Thu, 01 Jan 2004 23:19:00 +0000, david ford wrote:
>
> > What, if anything, is wrong with the following claim?:
> >
> > If 2 organisms have similar body structures, then they obtained those
> > similar structures from a common ancestor-- the similarities in the
> > structures are attributable to common descent from a common ancestor
> > that had the original version of the structure(s) in question.
>
> Nothing wrong, as long as you don't try to apply it to people. When you
> do that, you are going to inflame some people's "special act of creation"
> reflex. Their entire worldview is absolutely dependant on the notion that
> man is fundamentally different from other animals. If we "evolved" from
> pre-human hominids, that distinction doesn't hold, and their theology
> comes crashing down.
>
> The obvious solution is to do what theists have ALWAYS done when the
> physical evidence contradicts religious doctrine: persecute the scientist.
Minor quibble: Most theists have no problem with
"humans-related-to-broccoli" or any other part of evolution. It is
fundamentalist theists (and not all of them either) and
pseudoscientific anti-evolutionists, some of whom are self-proclaimed
agnostics and atheists, who persecute science.
DarwinistsforDonkeys
Date: 01/01/2004 6:57 PM Eastern Standard Time
Message-id: <3ff4b...@corp.newsgroups.com>
Randy Story wrote:
> "david ford" <dfo...@gl.umbc.edu> wrote in message
> news:b1c67abe.04010...@posting.google.com...
>
>>What, if anything, is wrong with the following claim?:
>>
>>If 2 organisms have similar body structures, then they obtained those
>>similar structures from a common ancestor-- the similarities in the
>>structures are attributable to common descent from a common ancestor
>>that had the original version of the structure(s) in question.
>
>
>
> If two bridges have common structural similarities does that mean that they
> have common anscentry or common design. I think common design.
Er, I've not noticed any bridges screwing and reproducing little bridges
as descendents. Have you?
LOLOLOL.......excellent point. I guess evilutionists just MUST resort to fairy
tales and magic to hold on to their faultering theory. No WONDER their theory
is taught in kids' science fiction books.
cheers
darwindiddrugs
Penny Nickels
"david ford" <dfo...@gl.umbc.edu> wrote in message
news:b1c67abe.04010...@posting.google.com...
What, if anything, is wrong with the following claim?:
If 2 organisms have similar body structures, then they obtained those
similar structures from a common ancestor-- the similarities in the
structures are attributable to common descent from a common ancestor
that had the original version of the structure(s) in question.
Penny writes:
Sounds like circular reasoning. But it doesn't alter the fact that
similarities are evidence for common ancestry.
Mike Ruskai
>What, if anything, is wrong with the following claim?:
>
>If 2 organisms have similar body structures, then they obtained those
>similar structures from a common ancestor-- the similarities in the
>structures are attributable to common descent from a common ancestor
>that had the original version of the structure(s) in question.
It ignores convergence. Something as vague as "similar body structures"
can easily be caused by two widely separated lineages (which, of course,
ultimately do have a common ancestor, but not one which provided the
"structures" in question) adapting to the same living conditions.
Typically, the ways in which the two organisms differ will be more
revealing than how they are similar, because of convergence (e.g. look at
respiratory systems rather than locomotive appendages in whales and fish).
Though some specific things (such as spines) are distinctive enough
solutions to imply common ancestry as the source of similarities, rather
than convergence.
In this day and age, however, DNA can clarify the issue without the
guesswork.
--
- Mike
Remove 'spambegone.net' and reverse to send e-mail.
John Wilkins
> "Randy Story" <rsto...@olypen.com> wrote:
> > "david ford" <dfo...@gl.umbc.edu> wrote in message
> > news:b1c67abe.04010...@posting.google.com...
> > > What, if anything, is wrong with the following claim?:
> > >
> > > If 2 organisms have similar body structures, then they obtained those
> > > similar structures from a common ancestor-- the similarities in the
> > > structures are attributable to common descent from a common ancestor
> > > that had the original version of the structure(s) in question.
> >
> >
> > If two bridges have common structural similarities does that mean that they
> > have common anscentry or common design. I think common design.
>
> And how do you think that "common design" is actuated in biology other
> than by descent with modification?
An engineer is a bridge's way of producing other bridges.
--
John Wilkins
"And this is a damnable doctrine" - Charles Darwin, Autobiography