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Author Topic:   Haeckel in Biology Textbooks
Beretta
Member (Idle past 5597 days)
Posts: 422
From: South Africa
Joined: 10-29-2007


Message 46 of 72 (483553)
09-23-2008 7:14 AM
Reply to: Message 43 by Modulous
09-22-2008 1:54 PM


Problems?
Is there some specific element about the pictures in the above, and the associated text, that you object to?
Well the appearance of the first stage drawings is far more like Haeckel's drawings and far less like the actual appearance which gives a false message.
Also the text states:
"You can see a rabbit embryo is more similar to a human embryo than it is to a fish embryo. This similarity provides one piece of evidence indicating that rabbits are more closely related to humans than they are to fishes."
Sentence one may or may not be true -the embryos I have pictures of do not include a rabbit but I have read more than enough embryologist's comments to know that the rabbit is probably not as similar as depicted in the picture. In fact they are all far too alike, far more like Haeckel would have liked them to be than they actually are so perhaps the text book writers copied them from Haeckel's drawings even though Haeckel isn't mentioned. Embryologists state that from their earliest stages different vertebrate embryos are easily identifiable and quite different from one another and I have a picture that illustrates the point but do not know how to insert my jpeg image. If you can tell me how, I'll post it. Certainly the fish and human embryos are far more different from one another than they are depicted in this textbook's image.
The problem with the second sentence is that evolution is assumed and relationship is assumed which is more easily done if pictures are altered to look far more similar than they actually are and the phylotypic stage (the midpoint) is shown rather than the first stages which are very different.

This message is a reply to:
 Message 43 by Modulous, posted 09-22-2008 1:54 PM Modulous has replied

Replies to this message:
 Message 47 by Percy, posted 09-23-2008 8:36 AM Beretta has not replied
 Message 48 by Modulous, posted 09-23-2008 9:14 AM Beretta has replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 47 of 72 (483561)
09-23-2008 8:36 AM
Reply to: Message 46 by Beretta
09-23-2008 7:14 AM


Re: Problems?
Beretta writes:
Well the appearance of the first stage drawings is far more like Haeckel's drawings and far less like the actual appearance which gives a false message.
Where are you getting your information about the "actual appearance". Please point us at this information. You can find tons of pictures of early embryos on the web, and across many species they are broadly similar - a curled up fishlike creature with eyes and tail.
I have a picture that illustrates the point but do not know how to insert my jpeg image.
You can send it to me at Percy and I'll make it available so you can include it in messages.
Certainly the fish and human embryos are far more different from one another than they are depicted in this textbook's image.
Not at the phylotypic stage they're not, which is what is depicted in the top row of the image in that textbook.
You're in a battle against reality. The criticism of Haeckel is that he made already very similar embryos, nearly identical to the uninformed eye, look more similar than they really were. You're trying to argue that what look like curled up tadpoles are actually significantly different. Good luck with that.
Beretta writes:
he problem with the second sentence is that evolution is assumed and relationship is assumed which is more easily done if pictures are altered to look far more similar than they actually are and the phylotypic stage (the midpoint) is shown...
The phylotypic stage is not the midpoint. In humans the phylotypic stage occurs at about 20 days, about 8% of term and about 4 months shy of midterm. While the time of the phylotypic stage as measured percentage-wise will vary across species, it definitely is way before the midpoint.
...rather than the first stages which are very different.
Except that the first stages are not very different, they're extremely similar. For example, how different can the very first stage, a single fertilized cell, be? Some embryos will be attached to yolks, some to placentas. Some will be larger, some smaller. These are superficial differences. That many very early embryos can be observed going through the same stages of cleavage, blastocyst, and gastrulation is more evidence of their similarity.
But though it is not true that embryos before the phylotypic stage are significantly different, it is true that there is less similarity than at the phylotypic stage, and this is because of the requirements of reproduction that can cause the initial conditions to vary so widely across the various species types. Yolk versus placenta for providing nutrients is just one of the more obvious examples of different initial conditions.
--Percy

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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 48 of 72 (483565)
09-23-2008 9:14 AM
Reply to: Message 46 by Beretta
09-23-2008 7:14 AM


Re: Problems?
Well the appearance of the first stage drawings is far more like Haeckel's drawings and far less like the actual appearance which gives a false message.
I won't significantly argue with you on it. I don't think they are terrible calamities of accuracy, but there are other more accurate pictures out there that make the same point.
This is the 2001 edition and you haven't said otherwise so is this page similar to the one you found in the 2007 book?
Sentence one may or may not be true -the embryos I have pictures of do not include a rabbit but I have read more than enough embryologist's comments to know that the rabbit is probably not as similar as depicted in the picture.
They do look pretty similar though and what's more the rabbit embryo does indeed look more similar to the human than the fish.
In fact they are all far too alike, far more like Haeckel would have liked them to be than they actually are so perhaps the text book writers copied them from Haeckel's drawings even though Haeckel isn't mentioned.
A quick look should reveal they are based on Haeckel's drawings. The question is - are the drawings they selected significantly problematic? I'd say they were problematic enough to warrant changing them - especially as I said, given that there are better pictures out there.
Embryologists state that from their earliest stages different vertebrate embryos are easily identifiable and quite different from one another and I have a picture that illustrates the point but do not know how to insert my jpeg image. If you can tell me how, I'll post it.
To the left of the text box there is the following:
quote:
HTML On (help)
dBCodes On (help)
Smilies Legend
Click (help) next to dBCodes On to find out. You can do it with HTML too, if you prefer - but the dBCodes are easier.
As for what embryologists state, I'm not in disagreement. I don't think Haeckel was in disagreement either. From what I know Haeckel was responsible in part for the 'hour-glass' model. Haeckel's diagrams start at the stage he claimed the embryos look most alike and chart things from there.
quote:
Nevertheless, no one
doubts that vertebrate embryos start out looking very
different, converge in appearance midway through
development (though not at the same time), then
become increasingly more different as they continue
toward adulthood - Richardson
This is in reference to the Richardson paper which was from the other side of embryology: he attempts to show that the hour-glass model is unsupported by the evidence. It's quite a complex paper, but interesting - we discussed here a while ago.
The problem with the second sentence is that evolution is assumed and relationship is assumed
No it isn't.
If evolution happens, then what changes evolution brings will be expressed during the development stage. We might expect that closely related animals would follow more similar developmental pathways than more distantly related animals.
That we see this, is one piece of evidence of relatedness. In the example given, "that rabbits are more closely related to humans than they are to fishes".
No need to assume evolution, one merely says 'if evolution is true, what should we expect to see? What observations are consistent with common ancestry?'. If your observations match up with this, you have a piece of evidence of how different animals might be related. Not conclusive on its own, of course.
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 46 by Beretta, posted 09-23-2008 7:14 AM Beretta has replied

Replies to this message:
 Message 54 by Beretta, posted 09-24-2008 6:35 AM Modulous has replied

  
Beretta
Member (Idle past 5597 days)
Posts: 422
From: South Africa
Joined: 10-29-2007


Message 49 of 72 (483577)
09-23-2008 9:38 AM
Reply to: Message 44 by Percy
09-22-2008 3:12 PM


Re: Haeckel and Darwin
The accusation against Haeckel is that he drew false representations of embryos to make them appear more similar than they really were. That these drawings may still appear in modern textbooks is the topic of this thread.
He drew false representations. Haeckel's drawings do seem to be reproduced in modern textbooks as can be seen from Modulous' example showing embryos in the phylogenetic stage looking far more similar than they really are - very much like Haeckel's in fact even though Haeckel's name doesn't appear. The one's in my book are just as similar -a series of fish, chicken, human and pig.
Thanks for the link anyway.

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Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 50 of 72 (483579)
09-23-2008 10:02 AM
Reply to: Message 49 by Beretta
09-23-2008 9:38 AM


Re: Haeckel and Darwin
I repeat my request of Message 33, please identify a single feature present in Haeckel's drawings that is not present in the real embryos?
(edit)
You can find photos (not drawings) of the Carnegie Stages of human embryos here, and of photos of Mice, Chicken, Fish, Amphibians and Sea Urchin embryos in various stages here
Edited by Mr Jack, : Provided links
Edited by Mr Jack, : No reason given.

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NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 51 of 72 (483580)
09-23-2008 10:04 AM
Reply to: Message 49 by Beretta
09-23-2008 9:38 AM


Similarities
And this is because they are actually very similar.
Why don't you do a bit of actual research and show images from a current text and actual pictures of the same stage. This would show if they are similar or not.

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Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 52 of 72 (483588)
09-23-2008 10:45 AM
Reply to: Message 50 by Dr Jack
09-23-2008 10:02 AM


Re: Haeckel and Darwin
Maybe it will help to put the pictures on the same page, so here we go.
Chick embryos:
Mouse embryos:
Human embryo at 30 days:
AbE: It looks to me like the chick at 15+ days, the mouse at 9.5 days, and the human at 30 days are most similar.
--Percy
Edited by Percy, : Add information about days.

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Replies to this message:
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bluegenes
Member (Idle past 2477 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


Message 53 of 72 (483756)
09-24-2008 4:42 AM
Reply to: Message 30 by Beretta
09-20-2008 4:55 AM


Re: Haeckel's excuses
Beretta writes:
If you look at the molecular level and see the way the different proteins function together to make the flagella work, the schematic is illustrating the principle apon which the motor works via the inter-related protein parts.
Haeckel lied completely misrepresenting his whole point and making the drawings fit the lie - putting the flagellar motor concept next to Haeckel's fraud is just plain ridiculous.
Didn't you understand the quote from Haeckel that Mr. Jack provided here Message 16?
He makes essentially the same claim that you are making for the schematics of flagella, using the word "diagramatic". I.D. advocates cannot accuse him of exaggeration and lying without hypocrisy. In reality, bacterial flagella have no neat appearance of design at all.
Here's someone accusing I.D.ers of the same thing that you're accusing Haeckel of. Some imaginative drawings from I.D.ers! Why doesn't Wells write a book criticising his friends, as they're pursuing the practices he so disapproves of right now, not in the 19th century.

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Beretta
Member (Idle past 5597 days)
Posts: 422
From: South Africa
Joined: 10-29-2007


Message 54 of 72 (483766)
09-24-2008 6:35 AM
Reply to: Message 48 by Modulous
09-23-2008 9:14 AM


Re: Problems?
If evolution happens, then what changes evolution brings will be expressed during the development stage. We might expect that closely related animals would follow more similar developmental pathways than more distantly related animals.
That we see this, is one piece of evidence of relatedness. In the example given, "that rabbits are more closely related to humans than they are to fishes".
The thing is they are not more closely related to humans than to fishes. If evolution is true, the embryos of rabbits and humans should look more closely related than do the embryos of fishes and humans BUT the sentence in the book by no means makes that clear -it just says:
This similarity provides one piece of evidence indicating that rabbits ARE more closely related to humans than they are to fishes.
Whats wrong with "If evolution is correct....rabbits may be more related to humans than they are to fishes."
The way the sentence is written is the way evolutionists like it since they think that evolution is a proven fact like gravity is a fact.
For us who are not convinced, the words indicate indoctrination rather than education because kids wouldn't even know the difference between evidence and proof -they think evidence is proof and so the article is saying that evolution is undoubtably true. Even without the problem with 'evidence' and 'proof', the impression of evolution being an unassailable fact is given clear as day.With embryos chosen so carefully, only at the perfect stage where they look most similar and only those species of embryos that are most fitting for the purpose of demonstrating that which evolutionists would have everyone believe; it is indoctrination pure and simple.

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 Message 48 by Modulous, posted 09-23-2008 9:14 AM Modulous has replied

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Beretta
Member (Idle past 5597 days)
Posts: 422
From: South Africa
Joined: 10-29-2007


Message 55 of 72 (483768)
09-24-2008 6:48 AM
Reply to: Message 52 by Percy
09-23-2008 10:45 AM


Re: Haeckel and Darwin
AbE: It looks to me like the chick at 15+ days, the mouse at 9.5 days, and the human at 30 days are most similar.
Looks to me like it illustrates my point well also -put them right next to each other and they are nowhere near as alike as they are depicted in textbooks -one wouldn't be able to get one's point across nearly as effectively with the real thing -I'm sure you'd have to agree that the different types are clearly distinguishable.

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Beretta
Member (Idle past 5597 days)
Posts: 422
From: South Africa
Joined: 10-29-2007


Message 56 of 72 (483770)
09-24-2008 6:56 AM
Reply to: Message 33 by Dr Jack
09-20-2008 5:57 AM


Re: Haeckel's Embryos -fake or not?
Can you identify a single labelled feature in Haeckel's drawings that is not present in the real embryos?
I don't think that's the point - most everybody on the earth has two eyes, one nose and a mouth but if somebody wanted to put across the point that we were all in some way related to some particular person from history like Genghis Khan perhaps, their use of artistic licence could illustrate that point without putting in any new anatomical features at all nor taking them out, just change them to make them all look more similar, it's easy.
That's what Haeckel did, giving a completely false and misleading impression to support his favorite theory.

This message is a reply to:
 Message 33 by Dr Jack, posted 09-20-2008 5:57 AM Dr Jack has replied

Replies to this message:
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mark24
Member (Idle past 5195 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 57 of 72 (483772)
09-24-2008 7:06 AM
Reply to: Message 56 by Beretta
09-24-2008 6:56 AM


Re: Haeckel's Embryos -fake or not?
Beretta,
I don't think that's the point
So your objection isn't Haeckel's embryo's at all, it's that comparative anatomy as evidence of evolution isn't evidence?
This would have been a lot quicker if you had said so at the beginning.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

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Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 58 of 72 (483774)
09-24-2008 7:10 AM
Reply to: Message 56 by Beretta
09-24-2008 6:56 AM


Re: Haeckel's Embryos -fake or not?
It's exactly the point; the features described by Haeckel do exist, and are most similar in more closely related species. You keep claiming fraud; when there is none. Haeckel's embryos are no more fraudulent than any other diagram.
That's what Haeckel did, giving a completely false and misleading impression to support his favorite theory.
Haeckel isn't trying to convince; he's trying to explain. Just as modern textbooks are.
The difference being of course, that Haeckel's theory was wrong.

This message is a reply to:
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Dr Jack
Member
Posts: 3514
From: Immigrant in the land of Deutsch
Joined: 07-14-2003
Member Rating: 8.7


Message 59 of 72 (483775)
09-24-2008 7:14 AM
Reply to: Message 55 by Beretta
09-24-2008 6:48 AM


Re: Haeckel and Darwin
Looks to me like it illustrates my point well also -put them right next to each other and they are nowhere near as alike as they are depicted in textbooks -one wouldn't be able to get one's point across nearly as effectively with the real thing -I'm sure you'd have to agree that the different types are clearly distinguishable.
As they are in the drawings.
Of course the features are clearer in the drawings; that's because - gasp - they're drawings. In the photos you have the embryos in different positions and poses, with different stains and in different lighting, you have the differences inherent between any two biological specimens and you have the difficulty of the untrained eye identifying the important features of a real specimen.
To be fraudulent, the drawings would have to show features that aren't there - they don't. And this remains the key point.

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Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 60 of 72 (483785)
09-24-2008 8:20 AM
Reply to: Message 52 by Percy
09-23-2008 10:45 AM


Embryo staging and comparative development
Was there any particular criterion for the choices of stages there?
All the chick ones are within about a day of each other while the mouse stages cover almost a week.
It looks to me like the chick at 15+ days
The chick numbers aren't days, a day 15+ chick embryo is practically hatched. Hamburger Hamilton stage 15, Hamburger Hamilton (HH) is the standard staging system for chicken development, is about 2-3 days worth of post fertilisation development.
If you took later human (Carnegie stage 14 maybe) and chick (say HH21) embryos they would also be very similar to the E10.5 mouse embryos.
For anyone really interested in comparative development the full text of the seminal Hamburger and Hamilton paper on chick development is available online as a PDF as is Karl Theiler's work on the development of the mouse available here. The only online version of the original Carnegie staging paper, here, has very poor figure reproduction. You would probably be better with a more modern atlas of human development like the Multidimensional Human Embryo although for earlier stages the UNSW pages are better.
TTFN,
WK
Edited by Wounded King, : No reason given.

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