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Evolution Of The Eye...


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#81 Guest_Keith C_*

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Posted 28 May 2009 - 10:15 AM

I like how the lens is a fuzzy spot and than it suddenly just appears... :lol:
.............................
Did you know that most evolutionists try to brush past the fact that the evo-perspective is now leaning towards believing that the eye independently formed over 40 different times?! That's quite a faith claim.

That one diagram spans 350,000 generations, so the gap between successive views is about 40,000 generations. I hardly think that is sudden appearance. You need to Google to read more information

I think your claim that the eye evolved independently 40 times is a little dated. It has been found that eye formation depends on certain hox genes, and therefore the more recent view seems to be that there is a sequence of hox and other genes involved. Pax6 is one of the initial genes to get eye formation switched on, then slightly different downstream genes account for differences in eye organization.
http://www.christs.c....php?page_id=g8

#82 Adam Nagy

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Posted 28 May 2009 - 11:45 AM

That one diagram spans 350,000 generations, so the gap between successive views is about 40,000 generations.  I hardly think that is sudden appearance.  You need to Google to read more information

I think your claim that the eye evolved independently 40 times is a little dated.  It has been found that eye formation depends on certain hox genes, and therefore the more recent view seems to be that there is a sequence of hox and other genes involved.  Pax6 is one of the initial genes to get eye formation switched on, then slightly different downstream genes account for differences in eye organization.
http://www.christs.c....php?page_id=g8

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All this is pure imagination with no substance. They are painting a tale as they look hither and yon. Any flabby pieces of data that they can pigeon hole into their preconceived biases are good fodder. Just hurry up and get it out there before it can be scrutinized. Cram it into the textbooks as quickly as possible, it will surely go nowhere, even long after it is proven wrong.

You still aren't answering any of my questions. Who cares if they claim there are 40,000 generation from no lens to lens, it's all deceptive speculation without any science.

Please tell us how a superior oblique muscle evolves.

Here is a good one... tell us how a solid mounted eye turns into a socketed rotating eye ball.

Please tell us how.

#83 chigaimasmaro

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Posted 28 May 2009 - 12:42 PM

That one diagram spans 350,000 generations, so the gap between successive views is about 40,000 generations.  I hardly think that is sudden appearance.  You need to Google to read more information

I think your claim that the eye evolved independently 40 times is a little dated.  It has been found that eye formation depends on certain hox genes, and therefore the more recent view seems to be that there is a sequence of hox and other genes involved.  Pax6 is one of the initial genes to get eye formation switched on, then slightly different downstream genes account for differences in eye organization.
http://www.christs.c....php?page_id=g8

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I have a curious question about the article. From what the article is suggesting we can all use similar gene components. How does that explain the formation of the eye itself? The way the article is written, I was left thinking "Well, isn't Pax6 like LEDs or regular light bulbs in car headlights? They may work for a mini cooper and a SUV." But that doesn't mean the cars themselves came from the same assembly line or the same factory does it?

And if natural selection DID form the eye, why did IT form the "blind spot' that was pointed out earlier? Wouldn't natural selection have kept the trait that allowed us to see infrared, night vision and more of our environment?

Edited by chigaimasmaro, 28 May 2009 - 12:53 PM.


#84 Bruce V.

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Posted 28 May 2009 - 01:02 PM

I have a curious question about the article.  From what the article is suggesting we can all use similar gene components.  How does that explain the formation of the eye itself? The way the article is written, I was left thinking "Well, isn't Pax6 like LEDs or regular light bulbs in car headlights?  They may work for a mini cooper and a SUV."  But that doesn't mean the cars themselves came from the same assembly line or the same factory does it?

And if natural selection DID form the eye, why did IT form the "blind spot' that was pointed out earlier?  Wouldn't natural selection have kept the trait that allowed us to see infrared, night vision and more of our environment?

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Heck with the eye how did Pax 6 evolve?

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The vertebrate PAX6 locus encodes at least three different protein isoforms, these being the canonical PAX6, PAX6(5a), and PAX6(ΔPD). The canonical PAX6 protein contains an N-terminal paired domain, connected by a linker region to a paired-type homeodomain, and a prolein/serine/threonine (P/S/T)-rich C-terminal domain. The paired domain and paired-type homeodomain each have DNA binding activities, while the P/S/T-rich domain possesses a transactivation function. PAX6(5a) is a product of the alternatively spliced exon 5a resulting in a 14 residue insertion in the paired domain which alters the specificity of this DNA binding activity. The nucleotide sequence corresponding to the linker region encodes a set of three alternative translation start codons from which the third PAX6 isoform originates. Collectively known as the PAX6(ΔPD) or pairedless isoforms, these three gene products all lack a paired domain.


Is Pax 6 part of abiogenesis and therefore a given: a starting point that we take for granted. Pax 6 is very complected and sophisticated in its own right.

#85 Bruce V.

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Posted 28 May 2009 - 01:15 PM

Evolution of the human eye

Very long article but worth reading.

Random quotes:

Living Optical Fibers

Posted Image

There are just a few problems with this "theory" of eye evolution however.   The argument is that the morphologic gaps are so narrow that it would be a very simple process to step from one gradation in visual acuity to the next with no more than one or two genetic mutations.  In fact, it is often argued that these gradations already exist in a population that expresses one of the above listed steps.  For example, a population that has flat eyespots is said to have at least some individuals within the population that have slightly dimpled eyespots.  If a change in selective pressures favored a dimpled eyespot with a slight increase in visual acuity, pretty soon the majority of the population would have dimpled eyespots.  The problem with this notion is that no population of creatures with flat eyespots shows any sort of intra-population range like this were even a small portion of the population has dimpled eyespots to any selectable degree.  This is a common assertion, but it just isn't true. 



Because of this requirement, whatever evolution happens to take place in the eye, must be backed up by equivalent evolution in brain development and interpretive powers.


Another potential problem is getting thousands of light-sensitive cells to work together in coordination at the same time to produce a dimpled effect.  What sort of simple mutation would produce such an effect among thousands of cells where each must be specifically oriented relative to all the others to form a "dimple" instead of a "protrusion" or some sort of other irregular surface? - at exactly the right spot to affect the light-sensitive spot in an orderly manner?


These are just a few of the reasons why the work of Nilsson and Pelger is still nothing more than a "paper theory" all these years later.  What seems to work very well on paper may not work so well when it comes to putting the paper theory to a real life test.  No such tests have actually been successful even though testing this theory isn't so hard to do

...

Such experimental demonstration has yet to be done.  If it were ever done, successfully, it would certainly create a sensation within the scientific community.  Creationism and intelligent design theorists would take a huge hit if such an experiment were actually successful.


To say then that the human eye is definite proof of a lack thoughtful design, is a bit presumptuous I would think.  This seems to be especially true when one considers the fact that the best of modern human science and engineering has not produced even a fraction of the computing and imaging capability of the human eye


Of course, there are many different kinds of bacterial motility systems possible, but all of them require several thousand fairly specified amino acids working together at the same time before the function of motility can be realized.  Such a level of functional complexity has never been observed to evolve through any sort of naturalistic process.



#86 Bruce V.

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Posted 28 May 2009 - 04:28 PM

Heck with the eye how did Pax 6 evolve?

Posted Image
Is Pax 6 part of abiogenesis and therefore a given:  a starting point that we take for granted.  Pax 6 is very complected and sophisticated in its own right.

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When I see the description of how the eye evolved it looked like a series of small step by step processes easily achievable. But if you get past the abstract aspects and work with the specific elements involved with each step they are no longer small incremental steps. Each step requires many new protein clusters working together doing specific things. So if you ask where any of the protein structures like PAX6 came from, for example, all you get is blank stares. Why, because it is a specific question and does not allow hand waving. Evolutions have no answer to something as simple as how PAX6 evolved: I mean simple in comparison to an integrated system like the eye/brain/muscle systems/nervous system/respiratory system(blood flow) ... that is required for sight.

#87 Guest_Keith C_*

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Posted 28 May 2009 - 07:39 PM

And if natural selection DID form the eye, why did IT form the "blind spot' that was pointed out earlier?  Wouldn't natural selection have kept the trait that allowed us to see infrared, night vision and more of our environment?

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This has an explanation of the blind spot.
http://en.wikipedia....tion_of_the_eye

Basically, evolution does not have the foresight to pick the best long-term solution.
With the first eyespots, the number of nerves involved was small and the blind spot insignificant. When the retina evolved to be larger and the nerves became more numerous it was too late to adopt the different alternative.

Again, color vision depends on the number of different opsin genes used, and the particular wavelengths for which each is most sensitive. Mutations readily change the range and so evolution can relatively select for the variants which work most effectively. The opposite side of this is that opsins which have no survival value would quickly be lost.

#88 CTD

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Posted 28 May 2009 - 08:01 PM

Mutations readily change the range and so evolution can relatively select for the variants which work most effectively.

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Oh, then that explains why so many people are born with infrared and ultraviolet vision. I always wondered about them.

#89 jason777

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Posted 28 May 2009 - 09:28 PM

I havn't read the whole thread so this may have been mentioned - if so my apologies.

The trilobite was found in Cambrian and I believe it is the first eye recorded in the fossil record. So how do these scientist know what the intermediate steps were: Hint, it wasn't the fossil record. Honestly. We can make up stories or hypotheticals all day long.

Creating a hypothetical sequence does not prove evolution.


Hi Bruce,

Sort of.Fossilized jellyfish are known from the precambrian and they have photosensitve cells rather than true eyes.It certainly is'nt transitional and jellyfish live in shallow water where true vision would be very useful,but they have'nt evolved eyes since they showed up ~570 million years ago. :lol:

http://www.gtj.org.u.../item/GTJ30436/ - 8k -

#90 jason777

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Posted 28 May 2009 - 10:42 PM

Basically, evolution does not have the foresight to pick the best long-term solution.
With the first eyespots, the number of nerves involved was small and the blind spot insignificant. When the retina evolved to be larger and the nerves became more numerous it was too late to adopt the different alternative.


The trick here is for genetic mutation to be able to account for completely turning the retina around backwards without mutating it and all the other hardware. :lol:

http://www.icr.org/i...on=view&ID=2476 - 22k -

#91 CTD

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Posted 29 May 2009 - 02:15 AM

The evolution of focused vision from a simple photo-sensitive light spot is well understood.  For very brief summary see:-
http://www.lu.se/vis...n-and-evolution
Such evolutionary steps would be extremely beneficial mutations if that increased the ability to detect prey (food) direction at greater distance, or could determine predator directions and allow escape.
Darwin's challenge to creationists to prove that vision could nor be explained by slow gradual modification was made 150 years ago, and still has not been met.

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The Nilsson and Pelger "study" is touted as meaning something, but it's really not impressive at all, as David Berlinski has explained. *

I have not yet seen any eye evolution story that did not start with an eye, and I doubt I ever shall. And if I'm mistaken, just think how many laughs it'd be good for!

I'm not familiar with "Darwin's challenge to creationists". The oft-quoted paragraph in his book ends "...the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real." Now maybe he can convince himself of things he cannot even imagine, but to me it looks more like bragging about his willpower than anything else.

What possible objection couldn't be overcome by such means? I can imagine electricity failing to flow. I can imagine gravity ceasing or reversing. I can imagine all sorts of unscientific things, and everyone will rightly stop me before I even get close to things that are too fantastic to even imagine. Thankfully I am not Darwin.

*Link contains the best typo I've seen in years: "Eugenic Scott" :lol:

#92 Guest_Keith C_*

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Posted 29 May 2009 - 10:23 AM

The trick here is for genetic mutation to be able to account for completely turning the retina around backwards without mutating it and all the other hardware. :lol:

I think I explained clearly that once evolution within a species latched onto one configuration (inverted or verted), then evolution has no mechanism to switch.
This is one of the crucial differences between evolution and intelligent design.

The truth is that the vertebrate eye developed from a very early creature which had light-sensitive genes expressed in its brain. The vertebrate eye, and eventually the mammalian eye, developed as projections of the brain. The octopus eye developed from light-sensitive cells on the surface. There was never a situation in which a retina needed to be flipped over!
For more details, see:-
http://scienceblogs....ebrate_eyes.php
For an animation showing how this sequence occurs in a vertebrate fetus, see:-
http://www.nature.co.../nrn2283-s1.swf

#93 Bruce V.

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Posted 29 May 2009 - 10:44 AM

I havn't read the whole thread so this may have been mentioned - if so my apologies.

The trilobite was found in Cambrian and I believe it is the first eye recorded in the fossil record. So how do these scientist know what the intermediate steps were: Hint, it wasn't the fossil record. Honestly. We can make up stories or hypotheticals all day long.

Creating a hypothetical sequence does not prove evolution.


Hi Bruce,

Sort of.Fossilized jellyfish are known from the precambrian and they have photosensitve cells rather than true eyes.It certainly is'nt transitional and jellyfish live in shallow water where true vision would be very useful,but they have'nt evolved eyes since they showed up ~570 million years ago. :lol:

http://www.gtj.org.u.../item/GTJ30436/ - 8k -

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Hi Jason,

Thank you for the link.

How do they know it had photosensitive cells. Any information pro or con is appreciated.

Also, how did you learn about fossils?


Bruce

#94 Bruce V.

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Posted 29 May 2009 - 11:18 AM

The Nilsson and Pelger "study" is touted as meaning something, but it's really not impressive at all, as David Berlinski has explained. *

I have not yet seen any eye evolution story that did not start with an eye, and I doubt I ever shall. And if I'm mistaken, just think how many laughs it'd be good for!

I'm not familiar with "Darwin's challenge to creationists". The oft-quoted paragraph in his book ends "...the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real." Now maybe he can convince himself of things he cannot even imagine, but to me it looks more like bragging about his willpower than anything else.

What possible objection couldn't be overcome by such means? I can imagine electricity failing to flow. I can imagine gravity ceasing or reversing. I can imagine all sorts of unscientific things, and everyone will rightly stop me before I even get close to things that are too fantastic to even imagine. Thankfully I am not Darwin.

*Link contains the best typo I've seen in years: "Eugenic Scott"   :lol:

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Berlinski last question:

FINAL QUESTIONS. Why, in the nine years since their work appeared, have Nilsson and Pelger never dissociated themselves from claims about their work that they know are unfounded? This may not exactly be dishonest, but it hardly elicits admiration. More seriously, what of the various masters of indignation, those who are usually so quick to denounce critics of Darwin's theory as carrying out the devil's work? Eugenic Scott, Barbara Forrest, Lawrence Krauss, Robert T. Pennock, Philip Kitcher, Kelly Smith, Daniel Dennett, Paul Gross, Ken Miller, Steven Pinker--they are all warm from combat. Why have they never found reason to bring up the matter of the mammalian eye and the computer simulation that does not exist?



#95 jason777

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Posted 29 May 2009 - 12:35 PM

Hi Jason,

Thank you for the link. 

How do they know it had photosensitive cells.  Any information pro or con is
appreciated.

Also, how did you learn about fossils?
Bruce


Honestly Bruce,precambrian jellyfish are just fossilized blobs and no one can say anything definitively about their morphology except that they were jellyfish.But fortunately,some in the cambrian were perfectly preserved and just like creationists predict,they are no different than their modern descendants.You could easily make a case for variation within a modern species.

http://www.scienceda...71030211210.htm - 51k -

You should also be aware that before the evidence was found,jellyfish were'nt supposed to have evolved until 200 million years later.Now they are known from the precambrian 70 million years older than that.

#96 Guest_Keith C_*

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Posted 29 May 2009 - 07:34 PM

Honestly Bruce,precambrian jellyfish are just fossilized blobs and no one can say anything definitively about their morphology except that they were jellyfish.But fortunately,some in the cambrian were perfectly preserved and just like creationists predict,they are no different than their modern descendants.You could easily make a case for variation within a modern species.
..........................................
You should also be aware that before the evidence was found,jellyfish were'nt supposed to have evolved until 200 million years later.Now they are known from the precambrian 70 million years older than that.

What the ScienceDaily article actually said was:-
"With the discovery of the four different types of jellyfish in the Cambrian, however, the researchers said that there is enough detail to assert that the types can be related to the modern orders and families of jellyfish. The specimens show the same complexity. That means that either the complexity of modern jellyfish developed rapidly roughly 500 million years ago, or that the group is even older and existed long before then."
'Related to the modern orders and families' is very different from being in the same species.

#97 scott

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Posted 29 May 2009 - 07:40 PM

What the ScienceDaily article actually said was:-
"With the discovery of the four different types of jellyfish in the Cambrian, however, the researchers said that there is enough detail to assert that the types can be related to the modern orders and families of jellyfish. The specimens show the same complexity. That means that either the complexity of modern jellyfish developed rapidly roughly 500 million years ago, or that the group is even older and existed long before then."
'Related to the modern orders and families' is very different from being in the same species.

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You miss the point, the point is that the jellyfish probably are the same species. Just by looking at the fossils and using common logic, we can figure this out. Just like looking at other fossilized remains from living animals.

Atheist just want to paint a picture of Millions upon Bagillions of years of evolution.

#98 Guest_Keith C_*

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Posted 30 May 2009 - 05:07 AM

You miss the point, the point is that the jellyfish probably are the same species.  Just by looking at the fossils and using common logic, we can figure this out. Just like looking at other fossilized remains from living animals.

Who is 'we' in your statement? Have you studied fossil jellyfish?

The particular fossils discussed in that news report are presented in more detail here:-
http://www.plosone.o...al.pone.0001121
The authors describe the particular details visible in their specimens. They also are specific that the similarity is to orders and not specific modern species.

Remember that jellyfish constitute an entire phylum, on the same level as chordata. - all creatures with a notochord.
Alternatively, are you trying to define 'kind' as an entire phylum. That would certainly reduce crowding on Noah's ark.

#99 Ron

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Posted 30 May 2009 - 05:22 AM

Alternatively, are you trying to define 'kind' as an entire phylum.  That would certainly reduce crowding on Noah's ark.

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There were no Jellyfish on Noah's Ark.

#100 jason777

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Posted 30 May 2009 - 01:16 PM

Remember that jellyfish constitute an entire phylum, on the same level as chordata. - all creatures with a notochord.
Alternatively, are you trying to define 'kind' as an entire phylum. That would certainly reduce crowding on Noah's ark.


Jellyfish are in the phylum cnidaria,which is comprised of thousands of families and genera.

The Cnidaria (pronounced nidaria)as a group of animals are well known to many people under their common names, Sea Anemones, Corals and Jellyfish are all Cnidarians as are Hydras, Sea Whips, Sea Fans and Sea Pansies. They are linked together by their carnivorous feeding habits their simple anatomical design and the possession of nematocysts, though one species of Ctenophora possesses nematocysts as well.

The name Cnidaria has now pretty much replaced the older term of Coelenterata (pronounced selenterata) which these days is often applied to both the Cnidaria and the Ctenophora together, these two phyla are also known as the Radiate Animals because they both have radial or biradial symmetry. The word Cnidaria refers to Cnidocysts, specialised cells which contain the Nematocysts, the stinging organelles that allow the Cnidaria to subdue their prey.

The Cnidaria are the oldest of the true metazoan phyla. A fossil Hydrozoan from South Australia called Ediacara is 700 million years old, while numerous fossil Cnidarians exist from the Cambrian 500 million years ago. The Cnidarians, particularly the corals often make up an important component of the shallow marine fauna of tropical and subtropical seas. All the Cnidaria are aquatic and nearly all are marine. Corals because of their shallow marine environment and their habit of accumulating a mineralised skeleton (coralite) tend to fossilize well and we know quite a bit about their evolution.

The Cnidarian body is basically a U shape with intact walls that surround a central digestive area and a mouth at the opening, generally surrounded by tentacles, there is no distinct anus. In Anemones the mouth faces up, and in Jellyfish it faces down. The Cnidarians show a more complicated arrangement of cell layers as well as a greater range of cell types than the Porifera. Their bodies show two distinct layers of cells and thus they are called 'Diploblastic animals'. The two cell layers are an outer Epidermis or Ectoderm, and an inner Gastrodermis or Endoderm. These two layers are separated by the mesoglea a non-cellular fibrous jelly like material that is thin in some groups such as the Hydras but can be quite thick in other such as the Jellyfish where it helps provide negative buoyancy (makes the animal more likely to float). The ectodermis consists of five basic cell types, Epitheliomuscular cells which supply some of the muscular capabilities of the animal, Interstitial cells which are basic cells that give rise to the other cell types, Cnidocysts (see below), Mucous glands and sensory or nerve cells. The endodermis consists of three or four basic cell types Gastromuscular cells which help digest food items and provide some muscle power, Gland cells that secrete enzymes for digestion, Mucous cells and in Anemones but not in Hydras, Cnidocytes.

One of the most important distinguishing characteristics of the phylum are the Nematocysts. Nematocysts, and their enclosing Cnidocysts come in about 24 different forms, the differences play a functional role in the classification of the phylum. A Cnidocyst is a cell that secretes a nematocyst within it. A basic Nematocyst is a capsule made of something like chitin within which rest a coiled thread. This thread can be shot out of the capsule to encounter prey items, or in some cases to repel predators. The Cnidocyst has either a modified flagellum called a Cnidocil, or a cone as a sensory trigger. If this trigger is touched the nematocyst thread is rapidly ejected. Nematocyst threads come in 3 basic types. The fundamental nematocyst is a thin tubular thread with barbs at the far end, though there may be barbs near the base as well. When the nematocyst is discharged, the barbs penetrate the skin of the prey and a toxin can be injected. Ptychocysts are uncommon, occurring only in the Ceriantharians, they lack spines or barbs but are adhesive and can be used to line the tubes the Ceriantharians live in as well as to entangle prey. Spirocysts also lack barbs or spines, they are an enclosed tube that is adhesive, they are used to trap prey in a tangled net of sticky threads.



I think your using this mischaracterization to imply that Creationists believe evolution occurs at the phylum level.

There is no demonstratable or experimental evidence that evolution can cross the species or genus level.




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