WinAce
2003-09-12, 20:23
This topic is intended to address an argument by well-poisoning that jester461 made in the 'Proof of God' topic, on page 4, concerning "haekels [sic] embryo drawings".
Comparative embryology does yield a good deal of evidence for evolution, and it doesn't rest on incorrect 19th century illustrations; species develop using common genetic mechanisms, structural development correlates rather well with the predictions gleaned from the fossil record, and embryos possess vestiges of their ancestral developmental stages.
But we'll go into that later.
The author of an oft-quoted recent article on Haeckel's embryonic drawings comments (http://talkorigins.org/faqs/wells/iconob.html#haeckel-embryo) on the popular creationist misconception that embryological evidence for evolution began and ended with Haeckel:
"We strongly disagree with this viewpoint. Data from embryology are fully consistent with Darwinian evolution. Haeckel's famous drawings are a Creationist cause célèbre. Early versions show young embryos looking virtually identical in different vertebrate species. On a *fundamental level*, Haeckel was correct: *All vertebrates develop a similar body plan* (consisting of notochord, body segments, pharyngeal pouches, and so forth). This shared developmental program reflects shared evolutionary history. It also fits with overwhelming recent evidence that development in different animals is controlled by common genetic mechanisms.
Unfortunately, Haeckel was overzealous. When we compared his drawings with real embryos, we found that he showed many details incorrectly. He did not show significant differences between species, even though his theories allowed for embryonic variation. For example, we found variations in embryonic size, external form, and segment number which he did not show (1). This does not negate Darwinian evolution. On the contrary, the mixture of similarities and differences among vertebrate embryos reflects evolutionary change in developmental mechanisms inherited from a common ancestor."
Moreover, neither Darwin nor the Modern Synthesis of his theory ever incorporated Haeckel's "improved" drawings of embryos as evidence.
As an interesting side note, Haeckel is not, in a strict sense, the originator of the concept; he applied a 19th century socio-philosophical view of development of organisms to evolutionary biology.
"In the early nineteenth century, however, the work of the "Naturphilosophen" gave the problem of ontogeny versus phylogeny a great deal of prominence. These thinkers, including such then-famous figures as Lorenz Oken and J.F. Meckel, viewed development as a process of successive addition: beginning with nothing, one entity is created, then another is added on, then another is added on, and so on. In this view, the parallel between ontogeny and phylogeny may be summarized as follows: 1) a more complex animal is, to within a high degree of approximation, a simpler animal with some extra organs added on; 2) this is how the embryo of a complex animal develops: first it grows into a simpler animal, then it grows the extra organs. The Naturphilosophen posited various universal laws of development, which were supposed to determine what sorts of structures were added on at what stages." - Ben Goertzel, author of the Evolving Mind
In addition, he was not a Darwinist. The view of evolution he would espouse would more aptly be described a variation of Lamarckian evolution. The 22nd chapter of Scott Gilbert's Developmental Biology contains a fairly good discussion on this.
"Second, there was the Law of Terminal Addition: the embryo evolved new species by adding a step at the end of the previus ones. In this view, humans evolved when the embryo of the next highest ape added a new stage. This provided a linear, not branching, phylogeny. This is a critically important departure from what is usually considered Darwinian evolution."
The author goes on to state, and I quote,
"This notion of ontogeny recapitulates phylogeny was not Darwinism. In fact, Haeckel's synthesis was an attempt to fuse the work of Darwin, Lamarck and Goethe. In Darwinism, contemporary species have a common ancestor. The result is a multi-branched 'bush'. A tree metaphor has also been used, but trees have a central axis, on which scientists have often placed the lineage leading up to H. sapiens. Humans are not 'higher' than chimps, but have an ancestor from which both groups diverged. In Haeckel's scheme, animals advance to new levels by adding stages to existing embryos. Humans were literally on top."
Additionally, it's quite irrelevant, as the erroneous concept Haeckel espoused was already falsified by the time he postulated it.
"Interestingly, von Baer (1828) had disproven the 'biogenetic law' before Haeckel ever invented it. In ridiculing the preevolutionary forms of this law, von Baer fantasized what would happen if birds were writing the embryology textbooks.
quote:"Let us imagine that birds had studied their own development and that it was they who investigated the structure of the adult mammal and of man. Wouldn't their physiological text books teach the following? "Those four and two-legged animals bear many resemblances to our own embryos, for their cranial bones are separated, and they have no beak, just as we do in the first five or six days of our incubation; their extremities are all very much alike, as ours are for about the same period; there is not a true feather on their body, rather only thin feather-shafts, so that we, as fledglings in the nest, are more advanced than they will ever be . . . And these mammals that cannot find their own food for such a long time after birth, that can never rise freely from the earth, want to consider themselves more highly organized than we?"
By observing development, von Baer noted that embryos never pass through the adult stages of other animals. However, there are stages that related embryos do share. All vertebrate embryos pass through a stage in which there are embryonic gill slits. Fish elaborate them into true gills, while the slits become part of the jaw or ear apparatus in other vertebrates. But a frog or human embryo never passes through a stage in which it has the structures of an adult fish. - Developmental Biology, 6th Edition
That's basically it for Haeckel; now on to some of the evidence.
Supporting Data for Common Descent Culled from Embryology
TalkOrigins notes (here (http://talkorigins.org/faqs/comdesc/section2.html#ontogeny)) that the modern version of Haeckel's biogenetic law is, ironically, exactly the opposite of what he argues for, "phylogeny recapitulates ontogeny".
"The modern developmental maxim *is the inverse of Haeckel's 'Biogenetic Law.'* 'Phylogeny recapitulates Ontogeny,' not the opposite. Walter Garstang stated even more correctly that ontogeny creates phylogeny. What this means is that once given knowledge about an organism's ontogeny, we can confidently predict certain aspects of the historical pathway that was involved in this organism's evolution (Gilbert 1997, pp. 912-914). Thus, embryology provides confirmations and predictions about evolution."
For the less technically-fluent among us, that means we can often take information on an organism gleaned from data like the fossil record and predict data that should be found in embryonic development. We can also do the converse, say, analyze embryonic development and predict a specific transitional structure that should have existed at one time in the fossil record.
Because Darwinian evolution often works by modifying existing structures to perform new functions, we can infer the ancestral function of a structure (which *shouldn't exist* if creationism is true!) by comparing how it and similar structures in different species develop in the embryo.
Now with that background in mind, we can take out the shovels and start digging!
"In 1837, a Creationist [Reichert] reported that during a pig's fetal development, *part of the incipient jawbone detaches and becomes the little bones of the middle ear*. After Evolution was invented, it was predicted that there would be a transitional fossil, of a reptile with a spare jaw joint right near its ear.A whole series of such fossils has since been found - the cynodont therapsids." - Don Lindsay (http://www.cs.colorado.edu/~lindsay/creation/evo_science.html)
The appropriately titled article the Gulf Between Mammals and Reptiles (http://www.geocities.com/osarsif/ce06.htm) quotes the Director of the Australian Museum in Sydney, Professor Michael Archer:
"In this regard, *studies of the embryological development of the modern mammal jaw articulation system and middle ear are very interesting.* Palmer (1913) followed their development *in a bandicoot*... When the young are born they are in effect two-week-old embryos. At this stage the young has a functional quadrate-articular jaw joint -- a normal reptilian system -- and uses it to open its tiny mouth very wide to grasp a teat in the pouch (Figure 6.8c). As the embryonic bandicoot develops in the pouch, the embryonic articular and quadrate become the malleus and incus of the middle ear. The angular matures between the articular and the dentary to become the ectotympanic for support of the developing tympanic membrane. The dentary develops posteriorly and the squamosal bone 'overgrows' the small malleus and incus to make contact with the dentary. By the time (less than sixty days later) that the young bandicoot first releases its grip on the teat it has, like all living mammals (Figure 6.8b) and most fossil mammals since the Middle Jurassic, a fully functional dentary-squamosal jaw articulation system and four 'free' bones in its middle ear.
While it is inappropriate to interpret ancestral adult conditions from the embryological conditions of descendants..., this embryological evidence strongly suggests that there is in living mammals *an intimate developmental relationship between the jaw articulation system and the bones of the middle ear.* This developmental relationship [color=purple]is precisely mirrored by what one finds in the fossil record of the reptile-to-mammal transition."
Let's see... we find that pig embryos detach parts of their (would-be) jawbones, jawbones that remain such in modern reptiles, and coopt them into the middle ear. These combined insights indicate an ancestral, reptile-like form of the pig must have used the structure as an actual jawbone.
Then we find a fossil of a reptile-like mammal that possesses pretty much the exact transitional structure we predicted. Yet another coincidence? Nope, chalk another one up for science!
TalkOrigins offers more detail at the same link (http://talkorigins.org/faqs/comdesc/section2.html#ontogeny).
"From embryological studies it is known that two bones of a developing reptile eventually form the quadrate and the articular bones in the hinge of the adult reptilian jaw (first reported in 1837 by the German embryologist Karl Reichert). However, in the marsupial mammalian embryo, the same two structures develop, not into parts of the jaw, but into the anvil and hammer of the mammalian ear. This developmental information, coupled with common descent, indicates that the mammalian middle ear bones were derived and modified from the reptilian jaw bones during evolution (Gilbert 1997, pp. 894-896).
*Accordingly, there is a very complete series of fossil intermediates in which these structures are clearly modified from the reptilian jaw to the mammalian ear* (compare the intermediates discussed in prediction 1.4 (http://talkorigins.org/faqs/comdesc/section1.html#morphological_intermediates_ex2)..."
http://talkorigins.org/faqs/comdesc/images/reptile_ear.gif" width="90" height="90 (http://talkorigins.org/faqs/comdesc/images/reptile_ear.gif" width="90" height="90) http://talkorigins.org/faqs/comdesc/images/human_ear.gif" width="90" height="90 (http://talkorigins.org/faqs/comdesc/images/human_ear.gif" width="90" height="90)
A comparison of the ears of reptiles and mammals. The reptile ear is shown on the left, the mammal ear on the right... the quadrate (mammalian anvil or incus) is in turquoise and the articular (mammalian hammer or malleus) is in yellow. The stapes is shown in brown. Note how the relative arrangement of these bones is similar in both taxa, in the order of inner ear-stapes-quadrate-articular.
The other diagram, which shows the transition from reptile jaw to mammalian middle ear in linear order, is too obnoxiously large to post, but anyone who wants to can go there (http://talkorigins.org/faqs/comdesc/section1.html#morphological_intermediates_ex2) and see for themselves.
The fact that these two independent lines of evidence are correlated is a startling example of the predictive power evolution has. Think about it for a moment.
If organisms don't have vestiges of an evolutionary history hidden in their genome, how could we gain any insights into what ancient life looked like merely by comparing extant organisms and embryos...?
Without common descent, you have no more reason to expect bones in an ancient mammal's skull to be *in an intermediate state between reptile jaw and ear bone* than you have expecting them to be in an intermediate state between beak and ear bone, the same arrangement as modern mammals, or a state totally unexpected and incongruent with phylogenetic predictions.
There are literally an infinite number of possibilities that could falsify evolution in this area, and (by chance?) ancient mammals just happen to magically possess the exact same hypothetical structure we confidently predicted they would based only on common descent coupled with a few modern observations.
To reiterate, how could creationism, which claims organisms have no evolutionary history, ever tell you the fossil history of an organism merely from the ways modern embryos develop and comparison of extant organisms?
Simple--it can't. Much as the suspect who accidentally reveals secret details about a murder only the police knew incriminates himself, so do embryos yield insights into the past history of their species and in so doing reveal themselves as the product of descent with modification.
If anything, this counts as a bona-fide falsification of the hypothesis that common descent isn't true. Creationism predicts we can gain no insights into evolutionary history from comparative anatomy and embryology, because it just isn't there (all organisms were specially created, not built by modifying existing ones). We can gain insights into evolutionary history by comparative anatomy, embryology, and other lines of evidence--thus, creationism is falsified.
There's also the additional matter of embryonic vestiges, like the human lanugo (fine hair) and tail, whale hind limb buds etc. I won't go into those here, yet, though.
Summary:
<LI>Ernst Haeckel's embryonic drawings are, in some aspects, fudged and embellished to the point where more accurate drawings or preferably photos should be used.
<LI>His biogenetic law has been, on the whole, known to be false since before it was authored. It was never particularly well-accepted among biologists even in its heyday.
<LI>Haeckel's ideas were primarily Lamarckian, not Darwinian.
<LI>Textbooks that teach such outdated concepts, assuming any exist outside of creationist imaginations, have a general problem with lack of peer review and/or funding, not just evolution.
<LI>The fact that textbooks are often error-laden in areas other than biology, such as history and physics, *but there's an inordinate amount of focus whenever a biology textbook is in error*, reveals some curious double standards...
<LI>Regardless of early misconceptions, comparative embryology provides overwhelming support for common descent that corroborates that drawn from totally independent lines of evidence like the genome and fossil record.
<LI>It's also *totally at odds with what creationism would predict*, namely, that we be unable to reconstruct any insights into archaic organisms from their modern counterparts, as they purportedly share no common ancestry.
[This message has been edited by WinAce (edited 09-12-2003).]
Comparative embryology does yield a good deal of evidence for evolution, and it doesn't rest on incorrect 19th century illustrations; species develop using common genetic mechanisms, structural development correlates rather well with the predictions gleaned from the fossil record, and embryos possess vestiges of their ancestral developmental stages.
But we'll go into that later.
The author of an oft-quoted recent article on Haeckel's embryonic drawings comments (http://talkorigins.org/faqs/wells/iconob.html#haeckel-embryo) on the popular creationist misconception that embryological evidence for evolution began and ended with Haeckel:
"We strongly disagree with this viewpoint. Data from embryology are fully consistent with Darwinian evolution. Haeckel's famous drawings are a Creationist cause célèbre. Early versions show young embryos looking virtually identical in different vertebrate species. On a *fundamental level*, Haeckel was correct: *All vertebrates develop a similar body plan* (consisting of notochord, body segments, pharyngeal pouches, and so forth). This shared developmental program reflects shared evolutionary history. It also fits with overwhelming recent evidence that development in different animals is controlled by common genetic mechanisms.
Unfortunately, Haeckel was overzealous. When we compared his drawings with real embryos, we found that he showed many details incorrectly. He did not show significant differences between species, even though his theories allowed for embryonic variation. For example, we found variations in embryonic size, external form, and segment number which he did not show (1). This does not negate Darwinian evolution. On the contrary, the mixture of similarities and differences among vertebrate embryos reflects evolutionary change in developmental mechanisms inherited from a common ancestor."
Moreover, neither Darwin nor the Modern Synthesis of his theory ever incorporated Haeckel's "improved" drawings of embryos as evidence.
As an interesting side note, Haeckel is not, in a strict sense, the originator of the concept; he applied a 19th century socio-philosophical view of development of organisms to evolutionary biology.
"In the early nineteenth century, however, the work of the "Naturphilosophen" gave the problem of ontogeny versus phylogeny a great deal of prominence. These thinkers, including such then-famous figures as Lorenz Oken and J.F. Meckel, viewed development as a process of successive addition: beginning with nothing, one entity is created, then another is added on, then another is added on, and so on. In this view, the parallel between ontogeny and phylogeny may be summarized as follows: 1) a more complex animal is, to within a high degree of approximation, a simpler animal with some extra organs added on; 2) this is how the embryo of a complex animal develops: first it grows into a simpler animal, then it grows the extra organs. The Naturphilosophen posited various universal laws of development, which were supposed to determine what sorts of structures were added on at what stages." - Ben Goertzel, author of the Evolving Mind
In addition, he was not a Darwinist. The view of evolution he would espouse would more aptly be described a variation of Lamarckian evolution. The 22nd chapter of Scott Gilbert's Developmental Biology contains a fairly good discussion on this.
"Second, there was the Law of Terminal Addition: the embryo evolved new species by adding a step at the end of the previus ones. In this view, humans evolved when the embryo of the next highest ape added a new stage. This provided a linear, not branching, phylogeny. This is a critically important departure from what is usually considered Darwinian evolution."
The author goes on to state, and I quote,
"This notion of ontogeny recapitulates phylogeny was not Darwinism. In fact, Haeckel's synthesis was an attempt to fuse the work of Darwin, Lamarck and Goethe. In Darwinism, contemporary species have a common ancestor. The result is a multi-branched 'bush'. A tree metaphor has also been used, but trees have a central axis, on which scientists have often placed the lineage leading up to H. sapiens. Humans are not 'higher' than chimps, but have an ancestor from which both groups diverged. In Haeckel's scheme, animals advance to new levels by adding stages to existing embryos. Humans were literally on top."
Additionally, it's quite irrelevant, as the erroneous concept Haeckel espoused was already falsified by the time he postulated it.
"Interestingly, von Baer (1828) had disproven the 'biogenetic law' before Haeckel ever invented it. In ridiculing the preevolutionary forms of this law, von Baer fantasized what would happen if birds were writing the embryology textbooks.
quote:"Let us imagine that birds had studied their own development and that it was they who investigated the structure of the adult mammal and of man. Wouldn't their physiological text books teach the following? "Those four and two-legged animals bear many resemblances to our own embryos, for their cranial bones are separated, and they have no beak, just as we do in the first five or six days of our incubation; their extremities are all very much alike, as ours are for about the same period; there is not a true feather on their body, rather only thin feather-shafts, so that we, as fledglings in the nest, are more advanced than they will ever be . . . And these mammals that cannot find their own food for such a long time after birth, that can never rise freely from the earth, want to consider themselves more highly organized than we?"
By observing development, von Baer noted that embryos never pass through the adult stages of other animals. However, there are stages that related embryos do share. All vertebrate embryos pass through a stage in which there are embryonic gill slits. Fish elaborate them into true gills, while the slits become part of the jaw or ear apparatus in other vertebrates. But a frog or human embryo never passes through a stage in which it has the structures of an adult fish. - Developmental Biology, 6th Edition
That's basically it for Haeckel; now on to some of the evidence.
Supporting Data for Common Descent Culled from Embryology
TalkOrigins notes (here (http://talkorigins.org/faqs/comdesc/section2.html#ontogeny)) that the modern version of Haeckel's biogenetic law is, ironically, exactly the opposite of what he argues for, "phylogeny recapitulates ontogeny".
"The modern developmental maxim *is the inverse of Haeckel's 'Biogenetic Law.'* 'Phylogeny recapitulates Ontogeny,' not the opposite. Walter Garstang stated even more correctly that ontogeny creates phylogeny. What this means is that once given knowledge about an organism's ontogeny, we can confidently predict certain aspects of the historical pathway that was involved in this organism's evolution (Gilbert 1997, pp. 912-914). Thus, embryology provides confirmations and predictions about evolution."
For the less technically-fluent among us, that means we can often take information on an organism gleaned from data like the fossil record and predict data that should be found in embryonic development. We can also do the converse, say, analyze embryonic development and predict a specific transitional structure that should have existed at one time in the fossil record.
Because Darwinian evolution often works by modifying existing structures to perform new functions, we can infer the ancestral function of a structure (which *shouldn't exist* if creationism is true!) by comparing how it and similar structures in different species develop in the embryo.
Now with that background in mind, we can take out the shovels and start digging!
"In 1837, a Creationist [Reichert] reported that during a pig's fetal development, *part of the incipient jawbone detaches and becomes the little bones of the middle ear*. After Evolution was invented, it was predicted that there would be a transitional fossil, of a reptile with a spare jaw joint right near its ear.A whole series of such fossils has since been found - the cynodont therapsids." - Don Lindsay (http://www.cs.colorado.edu/~lindsay/creation/evo_science.html)
The appropriately titled article the Gulf Between Mammals and Reptiles (http://www.geocities.com/osarsif/ce06.htm) quotes the Director of the Australian Museum in Sydney, Professor Michael Archer:
"In this regard, *studies of the embryological development of the modern mammal jaw articulation system and middle ear are very interesting.* Palmer (1913) followed their development *in a bandicoot*... When the young are born they are in effect two-week-old embryos. At this stage the young has a functional quadrate-articular jaw joint -- a normal reptilian system -- and uses it to open its tiny mouth very wide to grasp a teat in the pouch (Figure 6.8c). As the embryonic bandicoot develops in the pouch, the embryonic articular and quadrate become the malleus and incus of the middle ear. The angular matures between the articular and the dentary to become the ectotympanic for support of the developing tympanic membrane. The dentary develops posteriorly and the squamosal bone 'overgrows' the small malleus and incus to make contact with the dentary. By the time (less than sixty days later) that the young bandicoot first releases its grip on the teat it has, like all living mammals (Figure 6.8b) and most fossil mammals since the Middle Jurassic, a fully functional dentary-squamosal jaw articulation system and four 'free' bones in its middle ear.
While it is inappropriate to interpret ancestral adult conditions from the embryological conditions of descendants..., this embryological evidence strongly suggests that there is in living mammals *an intimate developmental relationship between the jaw articulation system and the bones of the middle ear.* This developmental relationship [color=purple]is precisely mirrored by what one finds in the fossil record of the reptile-to-mammal transition."
Let's see... we find that pig embryos detach parts of their (would-be) jawbones, jawbones that remain such in modern reptiles, and coopt them into the middle ear. These combined insights indicate an ancestral, reptile-like form of the pig must have used the structure as an actual jawbone.
Then we find a fossil of a reptile-like mammal that possesses pretty much the exact transitional structure we predicted. Yet another coincidence? Nope, chalk another one up for science!
TalkOrigins offers more detail at the same link (http://talkorigins.org/faqs/comdesc/section2.html#ontogeny).
"From embryological studies it is known that two bones of a developing reptile eventually form the quadrate and the articular bones in the hinge of the adult reptilian jaw (first reported in 1837 by the German embryologist Karl Reichert). However, in the marsupial mammalian embryo, the same two structures develop, not into parts of the jaw, but into the anvil and hammer of the mammalian ear. This developmental information, coupled with common descent, indicates that the mammalian middle ear bones were derived and modified from the reptilian jaw bones during evolution (Gilbert 1997, pp. 894-896).
*Accordingly, there is a very complete series of fossil intermediates in which these structures are clearly modified from the reptilian jaw to the mammalian ear* (compare the intermediates discussed in prediction 1.4 (http://talkorigins.org/faqs/comdesc/section1.html#morphological_intermediates_ex2)..."
http://talkorigins.org/faqs/comdesc/images/reptile_ear.gif" width="90" height="90 (http://talkorigins.org/faqs/comdesc/images/reptile_ear.gif" width="90" height="90) http://talkorigins.org/faqs/comdesc/images/human_ear.gif" width="90" height="90 (http://talkorigins.org/faqs/comdesc/images/human_ear.gif" width="90" height="90)
A comparison of the ears of reptiles and mammals. The reptile ear is shown on the left, the mammal ear on the right... the quadrate (mammalian anvil or incus) is in turquoise and the articular (mammalian hammer or malleus) is in yellow. The stapes is shown in brown. Note how the relative arrangement of these bones is similar in both taxa, in the order of inner ear-stapes-quadrate-articular.
The other diagram, which shows the transition from reptile jaw to mammalian middle ear in linear order, is too obnoxiously large to post, but anyone who wants to can go there (http://talkorigins.org/faqs/comdesc/section1.html#morphological_intermediates_ex2) and see for themselves.
The fact that these two independent lines of evidence are correlated is a startling example of the predictive power evolution has. Think about it for a moment.
If organisms don't have vestiges of an evolutionary history hidden in their genome, how could we gain any insights into what ancient life looked like merely by comparing extant organisms and embryos...?
Without common descent, you have no more reason to expect bones in an ancient mammal's skull to be *in an intermediate state between reptile jaw and ear bone* than you have expecting them to be in an intermediate state between beak and ear bone, the same arrangement as modern mammals, or a state totally unexpected and incongruent with phylogenetic predictions.
There are literally an infinite number of possibilities that could falsify evolution in this area, and (by chance?) ancient mammals just happen to magically possess the exact same hypothetical structure we confidently predicted they would based only on common descent coupled with a few modern observations.
To reiterate, how could creationism, which claims organisms have no evolutionary history, ever tell you the fossil history of an organism merely from the ways modern embryos develop and comparison of extant organisms?
Simple--it can't. Much as the suspect who accidentally reveals secret details about a murder only the police knew incriminates himself, so do embryos yield insights into the past history of their species and in so doing reveal themselves as the product of descent with modification.
If anything, this counts as a bona-fide falsification of the hypothesis that common descent isn't true. Creationism predicts we can gain no insights into evolutionary history from comparative anatomy and embryology, because it just isn't there (all organisms were specially created, not built by modifying existing ones). We can gain insights into evolutionary history by comparative anatomy, embryology, and other lines of evidence--thus, creationism is falsified.
There's also the additional matter of embryonic vestiges, like the human lanugo (fine hair) and tail, whale hind limb buds etc. I won't go into those here, yet, though.
Summary:
<LI>Ernst Haeckel's embryonic drawings are, in some aspects, fudged and embellished to the point where more accurate drawings or preferably photos should be used.
<LI>His biogenetic law has been, on the whole, known to be false since before it was authored. It was never particularly well-accepted among biologists even in its heyday.
<LI>Haeckel's ideas were primarily Lamarckian, not Darwinian.
<LI>Textbooks that teach such outdated concepts, assuming any exist outside of creationist imaginations, have a general problem with lack of peer review and/or funding, not just evolution.
<LI>The fact that textbooks are often error-laden in areas other than biology, such as history and physics, *but there's an inordinate amount of focus whenever a biology textbook is in error*, reveals some curious double standards...
<LI>Regardless of early misconceptions, comparative embryology provides overwhelming support for common descent that corroborates that drawn from totally independent lines of evidence like the genome and fossil record.
<LI>It's also *totally at odds with what creationism would predict*, namely, that we be unable to reconstruct any insights into archaic organisms from their modern counterparts, as they purportedly share no common ancestry.
[This message has been edited by WinAce (edited 09-12-2003).]