Ancestor, or sharer of a common ancestor?
david ford
Claim #1: If fossil organism A's first appearance in the fossil
record is older than the first appearance of fossil organism B,
and if A and B are roughly similar,
and if no other found/ discovered fossil organisms are as roughly
similar to B as A,
then we can confidently conclude that organism A transformed into
organism B.
Claim #2: If fossil organism A's first appearance in the fossil
record is older than the first appearance of fossil organism B,
and if A and B are roughly similar,
and if no other found/ discovered fossil organisms are as roughly
similar to B as A,
then we can confidently conclude that organisms A and B shared a
common ancestor residing in the recent past of A.
Insight into the question might appear within the thread "Similarities
& Common Descent," the first post therein being
http://tinyurl.com/2pvvn
John Harshman
david ford wrote:
By the way, does anybody have a theory about what Ford is trying to
accomplish with his "what, if anything" series? It escapes me.
Alan Morgan
It seems pretty clear that he's trying to show that evolution is such a
vague theory that absolutely any observed data can be used to support it.
Obviously a bad thing for a theory. Fortunatly (for evolution), he hasn't
got a clue what he is talking about.
Alan
--
Defendit numerus
JTEM
"david ford" <dfo...@gl.umbc.edu> wrote
> What, if anything, is wrong with the following 2 claims?:
> Claim #1: If fossil organism A's first appearance in the
> fossil record is older than the first appearance of fossil
> organism B, and if A and B are roughly similar, and if
> no other found/ discovered fossil organisms are as
> roughly similar to B as A, then we can confidently
> conclude that organism A transformed into organism B.
The error here is "convergence."
Steven J.
"david ford" <dfo...@gl.umbc.edu> wrote in message
news:b1c67abe.04011...@posting.google.com...
> What, if anything, is wrong with the following 2 claims?:
>
> Claim #1: If fossil organism A's first appearance in the fossil
> record is older than the first appearance of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are as roughly
> similar to B as A,
> then we can confidently conclude that organism A transformed into
> organism B.
>
statement) that in the middle ages, a certain cathedral claimed to have
among its relics not merely the skull of John the Baptist, but the skull of
John the Baptist as a child. If we have a fossil vertebrate, we can be
fairly confidently conclude that *that* organism did not, after leaving the
fossil, transform into anything. OTOH, many fossil arthropods (e.g. the
trilobites) shed their carapaces (the part that on occasion fossilized) like
modern arthropods, so you might find, in principle, two fossils from one
organism, showing its transformation as it matured and developed.
>
> Claim #2: If fossil organism A's first appearance in the fossil
> record is older than the first appearance of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are as roughly
> similar to B as A,
> then we can confidently conclude that organisms A and B shared a
> common ancestor residing in the recent past of A.
>
reasonably said to be "roughly similar" to a dolphin, or a thylacine to a
wolf, but it has rarely been suggested in either case that the former is the
ancestor of the other. I suppose the phrasing could be made more precise,
though I wonder whether the imprecision was deliberate -- an attempt to
elide the distinction made by comparative anatomists and taxonomists between
"homology" and "analogy."
[b] To get closer to home, australopiths are certainly roughly similar to
chimps, and appear in the fossil record before chimps (actually, there are
no fossils of chimps known), but only a few people have been impelled by
these facts to posit that chimps are living descendants of australopiths.
As you note in the title, many homologies are to be expected between
descendants of a recent common ancestor, and "roughly similar" species may
be different branches of the descendants of the same common ancestor. It's
not possible to be certain, no matter how many and close the homologies
between fossil species A and B, that there was not some third, unknown and
perhaps unfossilized, species C which was the actual ancestor of B, while C
was simply a sister group.
[c] The fossil record is extremely incomplete (note the number of extinct
species known from only a single, fragmentary specimen, and the number of
living species with no fossil representation at all). We aren't justified
in assuming that the earliest appearance of a species is the earliest time
it actually existed; B could actually have originated long before A, but
simply be known only from later specimens.
[d] By the same token, A could have originated later than -- or even be a
descendant of -- B, but simply known from older specimens (obviously, the
plausibility of this decreases as the number of specimens from different
sites increases). A species doesn't *have* to change over time, and most of
a species may persist unaltered while part of it evolves into a
(quite-possibly short-lived and local) different speces.
>
> Insight into the question might appear within the thread "Similarities
> & Common Descent," the first post therein being
> http://tinyurl.com/2pvvn
>
-- Steven J.
raven1
ford) wrote:
>What, if anything, is wrong with the following 2 claims?:
That you're posting them.
mel turner
[david ford] wrote...
>
>What, if anything, is wrong with the following 2 claims?:
>
>Claim #1: If fossil organism A's first appearance in the fossil
>record is older than the first appearance of fossil organism B,
>and if A and B are roughly similar,
"Roughly similar"? Why not say that A and B are closely similar
in sharing several specific homologous derived traits not
shared by the other known members of their larger group?
>and if no other found/ discovered fossil organisms are as roughly
>similar to B as A,
>then we can confidently conclude that organism A transformed into
>organism B.
Of course not. The known fossil record isn't ever going to be a
complete record of all organisms or all species that ever lived.
The most you can say is that A and B are one another's closest known
relatives and that they will have had a common ancestry not shared
with other known organisms. Both statements can change with new
fossil finds [or new studies of living organisms].
>Claim #2: If fossil organism A's first appearance in the fossil
>record is older than the first appearance of fossil organism B,
>and if A and B are roughly similar,
>and if no other found/ discovered fossil organisms are as roughly
>similar to B as A,
>then we can confidently conclude that organisms A and B shared a
>common ancestor residing in the recent past of A.
With the same quibbles about wording as #1, you blow it with the
"recent past" part, and for the same reason. How recent is recent?
The last common ancestor of A and B could easily have lived a very
long time before any known fossils of either A or B.
>Insight into the question might appear within the thread "Similarities
>& Common Descent," the first post therein being
>http://tinyurl.com/2pvvn
Yes, there were some good replies [and some less so] in that thread:
http://www.google.com/groups?threadm=b1c67abe.0401011520.5d1f4671%40posting.google.com
If you think you've got insights we don't, why not share
them here?
cheers
johac
dfo...@gl.umbc.edu (david ford) wrote:
If you have a better natural theory of evolution based on scientific
evidence, let's hear it. If your idea of of the origin of diversity of
species involves a supernatural being, let's see evidence for said
being's existence.
--
John Hachmann, aa #1782
- Question authority. Now more than ever. -
DrSilence1488
Nathan Baum
Nothing obviously wrong with those, except that I'd replace 'confidently
conclude that' with 'tentatively accept, in the absence of further
evidence, that'.
Have you become an evolutionist all of a sudden? :P
R. Baldwin
>
> Claim #1: If fossil organism A's first appearance in the fossil
> record is older than the first appearance of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are as roughly
> similar to B as A,
> then we can confidently conclude that organism A transformed into
> organism B.
We can confidently conclude that organism A died without transforming into
anything else. If it had metamorphosed into organism B than it would have
left no record as organism A.
If, however, you meant that the population of which organism A was a
representative evolved, giving rise to a population of which organism B was
a representative, that is not a conclusion you can confidently make from the
the order of appearance in the fossil record. Both populations may have
derived from a common ancestor, or population B may have derived from
population A.
>
> Claim #2: If fossil organism A's first appearance in the fossil
> record is older than the first appearance of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are as roughly
> similar to B as A,
> then we can confidently conclude that organisms A and B shared a
> common ancestor residing in the recent past of A.
A common ancestor would be probable, but it needn't be recent.
Dave Oldridge
20040110035131...@mb-m17.aol.com:
> What, if anything, is wrong with the following 2 claims:
>
> Claim #1: If fossil organism A's first appearance in
> the fossil record is older than the first appearance
> of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are
> as roughly similar to B as A,
> then we can confidently conclude that organism A
> transformed into organism B.
Who is making a claim like this? The best we can say is that organism A
MAY have given rise to organism B.
>
> Claim #2: If fossil organism A's first appearance in
> the fossil record is older than the first appearance
> of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are
> as roughly similar to B as A,
> then we can confidently conclude that organisms A and
> B shared a common ancestor residing in the recent past
> of A.
Depending on the degree of similarity, this is a reasonable conclusion
and it is born out not only by fossil evidence (which in itself is not
proof of ancestry) but also by genetic evidence in living organisms. We
have observed all the events necessary to create such a pattern.
--
Dave Oldridge
ICQ 1800667
Paradoxically, most real events are highly improbable.
John Hynes
What's wrong is that the very fact that there is a chronological
sequence in the fossil record disproves creationist statements about
special creation and flood geology.
No, wait, that would be what's RIGHT about it!
John Hynes
George
Buzzz.
You do not understand science.
Science does not have a 'roughly similar' measurement.
It is either or it is neither.
The lineage is now fairly well worked out and your 'animal' will fit
within the dates that it occupied...
Mark VandeWettering
They are both strawmen?
Mark
DarwinsMistress
From: dfo...@gl.umbc.edu (david ford)
Date: 12/01/2004 9:18 PM Eastern Standard Time
Message-id: <b1c67abe.04011...@posting.google.com>
#1) First, you have NO evidence of A transforming into B. You were not around
then, and ya did not see it happen, nor can you see any organism A transform
into B. Second, there are tons of other alternative conclusions someone can
come up with. Third, there could be fossils which have not been uncovered yet
which might show that B is as old as A, or even older.
#2) Your second point is actually pretty much the same as the first, but it has
some distinctions. Now, A and B maybe did not have a common ancestor. Maybe
they evolved separately or were designed so by a Designer. Common design is a
better alternative than Common descent. Also, you cannot know what A or B
looked like, since the facial features and their skin and the rest have
disappeared. So, as for example in the famous ape-men illustrations, what A and
B looked like is completely up to the artists imagination. Noone has ANY CLUE
whatsoever what this or that looked like. They are completely made up to fit a
preconcieved notion. As well, we cannot know how intelligent A or B were. Maybe
A was way more intelligent than B, how would common descent explain that? The
only typical answer is ''evolution did it'' This adapted better or had more
favourable mutations or some other nonsense. We know bigger brain size does not
mean greater intelligence, so we cannot tell by looking at the skulls. Another
problem is, as in the case of Lucy of whom 60 %
pf her fossils were never found, the fossils are simply incomplete. So,
scientists will make assumptions about how A or B looked like based on their
leaning and having an a priori commitment to darwinism not the objective truth.
Finally, there are a heck of a lot of other objections and obstacles to the
common descent hypothesis which i do not have time to write down here, but i
simply wanted to give you a general picture. C ya
cheers
''burn the creationist heretics for exposing the lie of
evolution!''-FundieHater
howard hershey
DrSilence1488 wrote:
> What, if anything, is wrong with the following 2 claims:
>
> Claim #1: If fossil organism A's first appearance in
> the fossil record is older than the first appearance
> of fossil organism B,
> and if A and B are roughly similar,
"roughly similar" is an inadequate test, since similarity can be due to
convergence as well as history. Similar in features that are unlikely
to be due to selection for an environmental niche. It is ignorant
people using intuitive ideas of "roughly similar" that causes the folk
wisdom of thinking whales are fish.
> and if no other found/ discovered fossil organisms are
> as roughly similar to B as A,
> then we can confidently conclude that organism A
> transformed into organism B.
No, you cannot "confidently conclude" this. Not unless you *know* that
the fossil record related to all these organisms is complete. And,
because the fossil record is necessarily 'gappy' by virtue of how often
and how fossils are generated, *knowing* that the fossil record is
complete is damn near impossible.
Moreover, if organism (species) A transformed into organism (species) B
with no intermediate species (that does seem to be what you are
concluding), the two species would be a lot more than merely "roughly
similar" (in most cases -- there may be a few exceptions, like in
autopolypoid speciations). These two organisms (A and B) would look
like members of the same "kind" to you and merely be dismissed as an
example of microevolution.
That said, in some cases, where the fossil record is good and reasonably
complete (that is, one keeps coming up with the same species rather than
frequently finding new ones), one can say, with *reasonable*, but not
perfect, confidence that A was most likely the parent species of B.
Take, as an example, the relationship between H. erectus and the oldest
H. sapiens.
>
> Claim #2: If fossil organism A's first appearance in
> the fossil record is older than the first appearance
> of fossil organism B,
> and if A and B are roughly similar,
The comments about "roughly similar" above still holds.
> and if no other found/ discovered fossil organisms are
> as roughly similar to B as A,
> then we can confidently conclude that organisms A and
> B shared a common ancestor residing in the recent past
> of A.
We can confidently state that A and B are more closely related by
descent to each other than either is to any other currently known
fossil, a position that includes both possibilities #1 and #2 (as well
as the possibility that B's presence as a more recent species is an
artifact of incomplete fossil record and several other less likely
possibilities).
It is very difficult, unless you *know* that the fossil record is
complete, to distinguish between these explanations *with full
confidence*. Some can be said to be more likely than others, given the
current available fossil evidence.
All these possible relationships that explain the similarities between
the two quite similar (in a detailed way that is not likely to be due to
convergence for a particular niche) fossils by descent with modification
are, of course, much more reasonable than the idea that the two
different organisms were independently poofed into existence and all
their similarities represent essentially arbitrary choices of an
unspecified, untestable creator who could have produced anything
he/she/it/they wanted to.
Peacenik
>
> Claim #1: If fossil organism A's first appearance in the fossil
> record is older than the first appearance of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are as roughly
> similar to B as A,
> then we can confidently conclude that organism A transformed into
> organism B.
It is very unlikely that you will find the direct ancestor of a fossil.
> Claim #2: If fossil organism A's first appearance in the fossil
> record is older than the first appearance of fossil organism B,
> and if A and B are roughly similar,
> and if no other found/ discovered fossil organisms are as roughly
> similar to B as A,
> then we can confidently conclude that organisms A and B shared a
> common ancestor residing in the recent past of A.
Change "confidently" to "tentatively, pending further study", and you would
have a more accurate statement. Biology is messy.
--
Peacenik
mel turner
drsile...@aol.com [DrSilence1488] wrote...
Why are you repeating David Ford's recent post?
Some posting glitch?
Ford's post FWIW:
Message-ID: <b1c67abe.04011...@posting.google.com>
http://groups.google.com/groups?selm=b1c67abe.0401121821.675a5dce%40posting.google.com
My reply to Ford:
http://groups.google.com/groups?selm=bu01au%244dg%243%40gargoyle.oit.duke.edu
cheers