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Author Topic:   Darwin Quotes, Corrections and Predictions
RAZD
Member (Idle past 1405 days)
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Joined: 03-14-2004


Message 1 of 3 (483291)
09-21-2008 1:40 PM


On another website a creationist presented this as a "quote" of Darwin. He did not give the source of his "quote" but one that lists this in the same wording is:
CREATION-EVOLUTION ENCYCLOPEDIA: SCIENTISTS SPEAK ABOUT EVOLUTION?
The "quote" is as follows:
quote:
"As by this theory, innumerable transitional forms must have existed. Why do we not find them embedded in the crust of the earth? Why is not all nature in confusion [of halfway species] instead of being, as we see them, well-defined species?"
”Charles Darwin, quoted in H. Enoch, Evolution or Creation (1966), p. 139.
Notice that this is a two-stage quote, a common signal of a quote-mine that misrepresents the actual words. It also demonstrates the lazyness of quoting from such pages and not checking it against the actual work in question.
The quote from Enoch does not tell where the "quote" is taken from, so we need to do a little (very little) searching to find out:
Darwin Online
Where you can read the complete works, see scanned images of the original documents, and most importantly for our purpose, search the complete works for certain phrases.
Searching for the phrases Enoch used one finds they come from two sections of the Origins of Species ("OoS" - in each of the several editions that were published)
quote:
Results 1-6 of 6 for +text:"as by this theory innumerable transitional forms must have existed"
100% F373 (page sequence 190)(page 172)
Book: Darwin, C. R. 1859. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.
London: John Murray. 1st edition, 1st issue.
... Hence, if we look at each species as descended from some other unknown form, both the parent and all the transitional varieties will generally have been exterminated by the very process of formation and perfection of the new form. But, as by this theory innumerable transitional forms must have existed, why do we not find them embedded in countless numbers in the crust of the earth? It will be much more convenient to discuss this question in the chapter on ...
and
quote:
Results 1-7 of 7 for +text:"why is not all nature in confusion"
100% F373 (page sequence 189)(page 171)
Book: Darwin, C. R. 1859. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.
London: John Murray. 1st edition, 1st issue.
... why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in confusion instead of the species being, as we see them, well defined? Secondly, is ...
The astute reader will notice that this comes from the page before the other quote, and that the proper quote would have been:
quote:
"Why is not all nature in confusion instead of the species being, as we see them, well defined? (p171) ... as by this theory innumerable transitional forms must have existed, why do we not find them embedded ... in the crust of the earth? (p172)
Thus we see the actual phrases are moved around and one is reworded and one phrase is inserted that is not part of the original words of Darwin, but an invention of Enoch. Comparing this again to his "quote"
quote:
"As by this theory, innumerable transitional forms must have existed. Why do we not find them embedded in the crust of the earth? Why is not all nature in confusion [of halfway species] instead of being, as we see them, well-defined species?"
”Charles Darwin, quoted in H. Enoch, Evolution or Creation (1966), p. 139.
We see that Enoch's false implication is two-fold: one that there are few transitionals when there should be innumerable, and two that these transitionals should be halfway defined species, incomplete, half-formed creatures, chimera, the common creationist misconception.
Darwin makes no such implication. A fuller quote from OoS page 171 dispels the first implication:
quote:
LONG before having arrived at this part of my work, a crowd of difficulties will have occurred to the reader. Some of them are so grave that to this day I can never reflect on them without being staggered; but, to the best of my judgment, the greater number are only apparent, and those that are real are not, I think, fatal to my theory.
These difficulties and objections may be classed under the following heads:” Firstly, why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in confusion instead of the species being, as we see them, well defined?
So he begins by saying that he expects the reader to wonder "why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms?" and he goes on to say he has an answer. That he has considered the question and provides an answer is contradictory to implying that he claims they should exist.
Likewise a fuller quote from OoS, page 172-176 dispels the second implication:
quote:
On the absence or rarity of transitional varieties.”As natural selection acts solely by the preservation of profitable modifications, each new form will tend in a fully-stocked country to take the place of, and finally to exterminate, its own less improved parent or other less-favoured forms with which it comes into competition. Thus extinction and natural selection will, as we have seen, go hand in hand. Hence, if we look at each species as descended from some other unknown form, both the parent and all the transitional varieties will generally have been exterminated by the very process of formation and perfection of the new form.
But, as by this theory innumerable transitional forms must have existed, why do we not find them embedded in countless numbers in the crust of the earth? It will be much more convenient to discuss this question in the chapter on the Imperfection of the geological record; and I will here only state that I believe the answer mainly lies in the record being incomparably less perfect than is generally supposed; the imperfection of the record being chiefly due to organic beings not inhabiting profound depths of the sea, and to their remains being embedded and preserved to a future age only in masses of sediment sufficiently thick and extensive to withstand an enormous amount of future degradation; and such fossiliferous masses can be accumulated only where much sediment is deposited on the shallow bed of the sea, whilst it slowly subsides. These contingencies will concur only rarely, and after enormously long intervals. Whilst the bed of the sea is stationary or is rising, or when very little sediment is being deposited, there will be blanks in our geological history. The crust of the earth is a vast museum; but the natural collections have been made only at intervals of time immensely remote.
But it may be urged that when several closely-allied species inhabit the same territory we surely ought to find at the present time many transitional forms. Let us take a simple case: in travelling from north to south over a continent, we generally meet at successive intervals with closely allied or representative species, evidently filling nearly the same place in the natural economy of the land. These representative species often meet and interlock; and as the one becomes rarer and rarer, the other becomes more and more frequent, till the one replaces the other. But if we compare these species where they intermingle, they are generally as absolutely distinct from each other in every detail of structure as are specimens taken from the metropolis inhabited by each. By my theory these allied species have descended from a common parent; and during the process of modification, each has become adapted to the conditions of life of its own region, and has supplanted and exterminated its original parent and all the transitional varieties between its past and present states. Hence we ought not to expect at the present time to meet with numerous transitional varieties in each region, though they must have existed there, and may be embedded there in a fossil condition. But in the intermediate region, having intermediate conditions of life, why do we not now find closely-linking intermediate varieties? This difficulty for a long time quite confounded me. But I think it can be in large part explained.
In the first place we should be extremely cautious in inferring, because an area is now continuous, that it has been continuous during a long period. Geology would lead us to believe that almost every continent has been broken up into islands even during the later tertiary periods; and in such islands distinct species might have been separately formed without the possibility of intermediate varieties existing in the intermediate zones. By changes in the form of the land and of climate, marine areas now continuous must often have existed within recent times in a far less continuous and uniform condition than at present. But I will pass over this way of escaping from the difficulty; for I believe that many perfectly defined species have been formed on strictly continuous areas; though I do not doubt that the formerly broken condition of areas now continuous has played an important part in the formation of new species, more especially with freely-crossing and wandering animals.
In looking at species as they are now distributed over a wide area, we generally find them tolerably numerous over a large territory, then becoming somewhat abruptly rarer and rarer on the confines, and finally disappearing. Hence the neutral territory between two representative species is generally narrow in comparison with the territory proper to each. We see the same fact in ascending mountains, and sometimes it is quite remarkable how abruptly, as Alph. De Candolle has observed, a common alpine species disappears. The same fact has been noticed by Forbes in sounding the depths of the sea with the dredge. To those who look at climate and the physical conditions of life as the all-important elements of distribution, these facts ought to cause surprise, as climate and height or depth graduate away insensibly. But when we bear in mind that almost every species, even in its metropolis, would increase immensely in numbers, were it not for other competing species; that nearly all either prey on or serve as prey for others; in short, that each organic being is either directly or indirectly related in the most important manner to other organic beings, we must see that the range of the inhabitants of any country by no means exclusively depends on insensibly changing physical conditions, but in large part on the presence of other species, on which it depends, or by which it is destroyed, or with which it comes into competition; and as these species are already defined objects (however they may have become so), not blending one into another by insensible gradations, the range of any one species, depending as it does on the range of others, will tend to be sharply defined. Moreover, each species on the confines of its range, where it exists in lessened numbers, will, during fluctuations in the number of its enemies or of its prey, or in the seasons, be extremely liable to utter extermination; and thus its geographical range will come to be still more sharply defined.
If I am right in believing that allied or representative species, when inhabiting a continuous area, are generally so distributed that each has a wide range, with a comparatively narrow neutral territory between them, in which they become rather suddenly rarer and rarer; then, as varieties do not essentially differ from species, the same rule will probably apply to both; and if we in imagination adapt a varying species to a very large area, we shall have to adapt two varieties to two large areas, and a third variety to a narrow intermediate zone. The intermediate variety, consequently, will exist in lesser numbers from inhabiting a narrow and lesser area; and practically, as far as I can make out, this rule holds good with varieties in a state of nature. I have met with striking instances of the rule in the case of varieties intermediate between well-marked varieties in the genus Balanus. And it would appear from information given me by Mr. Watson, Dr. Asa Gray, and Mr. Wollaston, that generally when varieties intermediate between two other forms occur, they are much rarer numerically than the forms which they connect. Now, if we may trust these facts and inferences, and therefore conclude that varieties linking two other varieties together have generally existed in lesser numbers than the forms which they connect, then, I think, we can understand why intermediate varieties should not endure for very long periods;”why as a general rule they should be exterminated and disappear, sooner than the forms which they originally linked together.
(yellow color for emPHAsis)
Note that he first discusses reproductively isolated but related species, each with distinct traits and no hybrid forms intermediate between them. Then he discusses the effect of geological isolation on the evolution of sub-populations, such that when reunited after sufficient time has passed that they have evolved differences and do not recognize the other populations as potential mates. Next he hypothesizes how populations can become reproductively isolated while inhabiting large but different areas while still having small hybrid zones with intermediate forms. Finally he notes that this pattern in time would result scarce transitional populations in small areas.
This in effect predicts speciation by geological separation, "punctuated equilibrium" and the population patterns of variations that we actually we see in ring-species.
Enjoy.

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AdminNosy
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Message 2 of 3 (483331)
09-21-2008 5:08 PM


Thread moved here from the Proposed New Topics forum.

Replies to this message:
 Message 3 by RAZD, posted 09-21-2008 6:34 PM AdminNosy has not replied

  
RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 3 of 3 (483356)
09-21-2008 6:34 PM
Reply to: Message 2 by AdminNosy
09-21-2008 5:08 PM


Darwin's Predictions: Speciation, Punkeek, and Ring Species
Thank you Ned. I broke this into two parts as they were getting (shock!) too long.
One example that easily sums up Darwin's predictions for speciation by geographical isolation, the development of new species through small intermediate populations (ie - punkeek) and the existence of living populations that exhibit the same pattern of large populations of dominant varieties and small populations of intermediate varieties (ie - hybrids in modern genetic language) is the existence of ring species.
One ring species that shows this pattern vividly, is the Asian Greenish Warblers
quote:
Greenish warblers (Phylloscopus trochiloides) inhabit forests across much of northern and central Asia. In central Siberia, two distinct forms of greenish warbler coexist without interbreeding, and therefore these forms can be considered distinct species. The two forms are connected by a long chain of populations encircling the Tibetan Plateau to the south, and traits change gradually through this ring of populations.
Map of Asia showing the six subspecies of the greenish warbler described by Ticehurst in 1938. The crosshatched blue and red area in central Siberia shows the contact zone between viridanus and plumbeitarsus, which do not interbreed. Colors grade together where Ticehurst described gradual morphological change. The gap in northern China is most likely the result of habitat destruction.
(image mirrored off original website to reduce bandwidth intrusion)
As you can see, there are six areas that are dominated by a specific variety and three hybrid zones where there is overlap between existing varieties. One hybrid zone to the nitidus variety has been lost in time, and another in northern China is due to modern habitat loss.
We also have an area of overlap in northern Tibet, but here, instead of a hybrid zone we have:
quote:
These representative species often meet and interlock; and as the one becomes rarer and rarer, the other becomes more and more frequent, till the one replaces the other. But if we compare these species where they intermingle, they are generally as absolutely distinct from each other in every detail of structure as are specimens taken from the metropolis inhabited by each.
The varieties are reproductively isolated, and neither one sees the other as potential mates.
Thus speciation by geological isolation over time and reproductive isolation when they again come into contact has occurred, just as predicted by Darwin.
We can also look at this map and see it as a history of the spread of the Asian Greenish Warbler around the Tibetan Plateau, likely starting near nitidus (according to the article).
As it moves into new and different ecologies it evolves in stages, all by variations in hereditary traits in the populations from generation to generation and by the natural selection for each of the new ecologies.
But the survival and reproductive success of populations is also related to the size of the populations, where larger populations have an advantage over smaller populations (see Darwin above), thus any new variety that is capable of expanding to fill a larger area than it's cousins will over time fill and replace the lesser variations in those areas and come to dominate a new area with a new variety different from the original, and the existence of the intermediate forms would be limited to small areas (where they may continue to exist as hybrid zones) and a brief amount of time in the areas dominated by the large populations.
How long does it take for a small population to dominate a large area? Not very long, especially for birds: about 60 European Starlings were introduced in 1890 at New York City, and in 60 years they had large flocks covering North America.
Such rapid spread is assisted by a lack of predators for the new species, and a lack of natural diseases from closely related species that are now left behind. The better the new species is adapted to a variety of ecologies, the better it will succeed as well.
Thus "punctuated equilibrium" is predicted by Darwin.
Finally, when Darwin says:
quote:
If I am right in believing that allied or representative species, when inhabiting a continuous area, are generally so distributed that each has a wide range, with a comparatively narrow neutral territory between them, in which they become rather suddenly rarer and rarer; then, as varieties do not essentially differ from species, the same rule will probably apply to both; and if we in imagination adapt a varying species to a very large area, we shall have to adapt two varieties to two large areas, and a third variety to a narrow intermediate zone. The intermediate variety, consequently, will exist in lesser numbers from inhabiting a narrow and lesser area; and practically, as far as I can make out, this rule holds good with varieties in a state of nature.
He is predicting the existence of ring species, and that they will sort into large populations of dominant varieties and small areas of hybrid zones.
We see this pattern with the Asian Greenish Warbler, and we also see it with: Ensatina salamanders of the Pacific coast, and the Herring Gull (although there is some dispute about the Herring Gull not being a ring species: instead it may be a different example of speciation that has overlaps and has preserved the ancient hybrid zone between diverging populations - even better confirmation of Darwin's comments).
Enjoy.
Edited by RAZD, : added link

we are limited in our ability to understand
by our ability to understand
Rebel American Zen Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

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 Message 2 by AdminNosy, posted 09-21-2008 5:08 PM AdminNosy has not replied

  
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