The Neck of the Giraffe

@wolfgang59 said
No species in the entire history of Life on
this planet has ever given birth to another species.

Something Creationists cannot seem to grasp.

@ghost-of-a-duke said
A friend here recently shared the following thoughts with me which I thought warranted a thread of its own. (He may appear to contribute, but won't name him in case he doesn't).

'The Neck of the Giraffe' (written by Francis Hitching) postulates that evolution of species has not and certainly has not always been a slow, gradual and incremental thing, but rather has ...[text shortened]... s.
It's an interesting theory, at least, and purports to explain huge gaps in the fossil record. '

@kazetnagorra said
There are a number of misconceptions in your post; I apologize if some or all of them have been dealt with elsewhere in the thread as I did not read all of it.

First of all, it is not true that giraffes have long necks to reach high leaves and such. It is an example of sexual selection: male giraffes use their necks in combat to establish dominance and thus access fem ...[text shortened]... ary history of most large mammals pretty well.
Read more: https://en.wikipedia.org/wiki/Samotherium

@kazetnagorra said

First of all, it is not true that giraffes have long necks to reach high leaves and such. It is an example of sexual selection: male giraffes use their necks in combat to establish dominance and thus access females.
Read more: https://en.wikipedia.org/wiki/Giraffe#Necking

@ghost-of-a-duke said
On that point, opinions still differ.

Jean-Baptist Lamarck, in his work Philosophie ZoologiqueIt, commented, 'it is interesting to observe the result of habit in the peculiar shape and size of the giraffe: this animal, the tallest of the mammals, is known to live in the interior of Africa in places where the soil is nearly always arid and barren, so that it is obl ...[text shortened]... d generally have survived...'


Read more at: http://natureinstitute.org/pub/ic/ic10/giraffe.htm

@kellyjay said
I don't believe in a common ancestor for all life, which backs up what you just
said. Even through small changes in DNA I don't believe that it has occurred at
all either moving from one type into a completely other. So the sudden burst of
different lifeforms you disagree with as well?

@kazetnagorra said
First of all, it is not true that giraffes have long necks to reach high leaves and such. It is an example of sexual selection: male giraffes use their necks in combat to establish dominance and thus access females.

@kazetnagorra said
We've learned a lot about evolution and evolutionary history in particular since Darwin's time.

@wolfgang59 said
I'm sure there is evolutionary pressure on males to be better equipped
for fighting by having longer necks but that does not explain long necks
in females. Furthermore before they evolved long necks they probably
kicked each other to death. No initial pressure to develop longer necks.

A classic example of extreme morphological adaptation to the environment is the neck of the giraffe (Giraffa camelopardalis), a trait that most biologists since Darwin have attributed to competition with other mammalian browsers. However, in searching for present-day evidence for the maintenance of the long neck, we find that during the dry season (when feeding competition should be most intense) giraffe generally feed from low shrubs, not tall trees; females spend over 50% of their time feeding with their necks horizontal; both sexes feed faster and most often with their necks bent; and other sympatric browsers show little foraging height partitioning. Each result suggests that long necks did not evolve specifically for feeding at higher levels. Isometric scaling of neck-to-leg ratios from the okapi Okapia johnstoni indicates that giraffe neck length has increased proportionately more than leg length-an unexpected and physiologically costly method of gaining height. We thus find little critical support for the Darwinian feeding competition idea. We suggest a novel alternative: increased neck length has a sexually selected origin. Males fight for dominance and access to females in a unique way: by clubbing opponents with well-armored heads on long necks. Injury and death during intrasexual combat is not uncommon, and larger-necked males are dominant and gain the greatest access to estrous females. Males' necks and skulls are not only larger and more armored than those of females' (which do not fight), but they also continue growing with age. Larger males also exhibit positive allometry, a prediction of sexually selected characters, investing relatively more in massive necks than smaller males. Despite being larger, males also incur higher predation costs than females. We conclude that sexual selection has been overlooked as a possible explanation for the giraffe's long neck, and on present evidence it provides a better explanation than one of natural selection via feeding competition.

@kazetnagorra said
We conclude that sexual selection has been overlooked as a possible explanation for the giraffe's long neck, and on present evidence it provides a better explanation than one of natural selection via feeding competition.[/quote]

@wolfgang59 said
I agree with your article ... it's possible explanation. But the initial selection of longer
necked giraffes would have been due to a feeding advantage THEN (when the necks
became weapons) there would also have been pressure on longer necks for fighting.

@kellyjay said
How do you believe natural selection causes changes in DNA?

Does it just filter out the weak?
Does it create new features for advantages too for no reason?
Does it know all the new features require these changes to enhance the neck length?

Small slow changes over time, building longer necks, because something eats
more with longer necks. DNA would know to do this ho ...[text shortened]... and not that one?

We are not talking video games here, but a blind undirected process supposedly.

@wolfgang59 said
I agree with your article ... it's possible explanation. But the initial selection of longer
necked giraffes would have been due to a feeding advantage THEN (when the necks
became weapons) there would also have been pressure on longer necks for fighting.

I've read both and still the issue is that what you are suggesting. Alterations due
to activities are being pushed into DNA causing specific changes in the code. This
pushing of alterations within the code means genetic mutations are not random
in nature but are taking directions from the activities of the adults.
(reaching for food higher up).

I've written code to accomplish things at work, I know we can write code so that a
machine can mimic movements of a painter, as forklifts get painted on an
assembly line for example. This reduces variation of the job since the machine can
continue repeating the same movements each time; human interaction then gets
eliminated because of cost prohibitions. That must be setup, machines just don’t
naturally mimic painters, the code had to be in place before that skill was acquired.

Translating activities into building instructions into DNA is a very peculiar and
specific ability, it doesn’t just occur. This doesn't explain anything new either, DNA
is a genetic code for building instructions, so it is doing what the code is
supposed to do, take what is already there, pass it on to what is coming in the
next generation. Things like acquiring a neck in the first place isn't addressed by
this, let along having some creatures have a neck of inches long and another
measured by feet.

@wolfgang59 said
I agree with your article ... it's possible explanation. But the initial selection of longer
necked giraffes would have been due to a feeding advantage THEN (when the necks
became weapons) there would also have been pressure on longer necks for fighting.