Posted: May 01, 2012 12:20 pm
asyncritus wrote:Spearthrower. I owe you a debunking, and here it is.
Oh deary me, Async.
You really do think you're capable, don't you?
It's embarrassing.
asyncritus wrote:What do you mean 'get into the genome'? What does that actually mean? It's already in the genome, it's the expression of the genome... it's not magically floating around in potential bird space waiting to be alighted on.
Since it was not present in the UCA, then where is it?
It IS the DNA - how many times do I have to spell this out to you? I explained this via bees 2 years ago, and you still persist in wallowing in ignorance.
I showed you how particular sections of bee DNA could be suppressed and they suddenly lost previously ubiquitously held traits.
Do you find that difficult to process? The traits ARE the DNA - yes, even behavioural ones! Of course, we're all well aware that neural circuitry in animals is also of great import - but then again, how are those neural circuits built? Ohh by DNA.
Did you get it yet, or do you want me to go back over the information yet again? I guess I might be being unfair here, and you're just struggling desperately to learn things that are clearly outside your ken.
But it's the attitude thing that makes me not want to help you and instead laugh at the ineptness that's at the core of all that hubris.
asyncritus wrote:You have a population of birds living across an environment from optimal feeding grounds to non-optimal feeding grounds. As seasons change, as climate changes over millenia, these optimal and sub-optimal grounds shift. Birds would have started moving to wherever the food was or died (actually, numerous, probably the majority of species of birds did just that). That's partially genetically influenced, as in the drive to eat etc, but the actual specifics don't need to be encoded into the gene.
Good so far.
Well thanks, so nice of you to accept observations from reality. We might make a scientist of you yet!
asyncritus wrote:There's not a map written in DNA with an alarm clock saying - move north 2 miles on October 3rd, land, eat, then fly 2 miles further.
That’s curious, and not consistent with the facts. Let me remind you that the swallows arrive at the specific location in Capistrano on the 18th March precisely, every year, and leave on Oct 23rd.
And I've told you before that this is not true. That's the median day they arrive and leave. Repeating falsehoods doesn't make for a very strong case, does it?
Now, let's recall (sigh yet again) the notion of being a biological organism. You need to eat. You need to breed. You need to raise your young.
How does one do that if one isn't a gregarious species, and lives in remote isolation? Well, how about if everyone's timing is the same, and everyone goes to the same location at the same time?
If you imagine a small population that is not very widely segregated, and you recall the notion of seasonal feeding grounds, you might well see how this could arise. You'd also presumably be able to work out how variations in this DNA would be harshly punished - no shagging for you if you arrive late, and consequently no offspring carrying your fashionably late gene.
asyncritus wrote:They must, therefore, have a GPS and a calendar built in somewhere.
Err no... they need neither. As I've taken pains to explain to you before. Now, they may have something akin to that - the existence of biological rhythms is universal in all organisms. Why do you sleep at night? Why do dogs grow a coat before it gets cold? Again, what you're fumbling around for, in the ignorance of the relevant topic, is chronobiology. Yes, people know about this shit. Yes, people have studied it. One of those wondrous things about science is that we don't have to reinvent the wheel - well, just so long as we don't assume we're far too intelligent to deign to look at other people's wheel designs, and set about building our square one.
Try doing some research... it really helps if you want to know what you're talking about - seriously.
asyncritus wrote:So
a. How did it get it wherever it is and
b. What mechanism do you propose for its origin?
Mutations, natural selection.
How many times do you need this repeated? If you aren't going to accept it as an answer, then challenge it. The fact is that you don't actually understand it as an answer - that's the plain truth, if only you'd admit it to yourself. Thus you keep regurgitating the same question but just use a different organism instead.
Wouldn't you like to actually get to the point? Even if you don't believe it, even if you think you've got a good enough case, isn't it time you actually looked into this? What are mutations? What is natural selection? I don't think you have the foggiest, do you?
asyncritus wrote:Instead, there would have been variation in the population. Some birds would have stayed where they were and eked out a living on sub-optimal grounds and consequently gained adaptive traits that improved their survivability, others would have travelled further and further in search of food.
I don’t think anybody disputes this.
Who knows what you accept and don't - it's beyond my capacity to guess what perfectly normal fact you are suddenly going to reject, so I'd best spell it all out!
asyncritus wrote:Over the generations, those birds whose genetic traits encouraged this behaviour would be retained, as they'd be passed onto their surviving offspring. Over the generations, these traits would have become more stringent with respect to the changing environment. They tied themselves into a survival strategy, and consequently there would be a strong selection pressure on their ability to traverse the world in this way as it's precisely how they survive.
But I see no explanation of
a. how a specific geographical location 7,800 miles away becomes programmed into the genome and
b. how a specific date becomes programmed in at the same time.
a) Because it was (at least the general location) held by numerous generations, thereby fixing it ever more solidly into the genome. Other behaviours and adaptations dovetailed onto this, if you'll excuse the pun, making it ever-increasingly of import to that particular species.
b) There's not a specific date. There are specific seasonal variations. Arrive late, miss the food or don't get laid. Thereby, your tardy gene doesn't survive in the population.
There are reams of papers on this... really hundreds, possibly thousands on evolutionary stable strategies. Again, considering the time and effort you put into 'debunking' this on the net, why is it you seem so blithely unaware of... well, just about everything relevant?
asyncritus wrote:If you said ‘specific season’, I might agree with you, but a specific date? No chance.
The specific date you keep touting is some kind of urban myth in your head. The date is a median.
asyncritus wrote:The return journey also presents a difficulty. How do the birds acquire the information needed to return, since the geographical and astronomical features are now in reverse order?
I fail to see how this is problematic if you accept the first. We can even ignore all geographical and astronomical features and reconsider the eel - the type of directive its working to is not a map like you're thinking. It's following senses in temperature, salinity, currents etc that match the genetically controlled drives, or whatever preferred word you'd use. So with the birds, they are following seasonally available food sources, they are assessing air temperatures, wind currents, sunlight duration, humidity, etc etc - the whole world is a clock if you know the signs to look for - even people can learn them. In fact, you don't even need to learn them, as I already said - why is it that people sleep at night and wake in the day? There's no difference in this whatsoever.
asyncritus wrote:And then they pass down the ACQUIRED information to their offspring. Not allowed.
Woahhh there! Where did that 'acquired' suddenly spring into the equasion? There's no justification for that? Even if there was, it doesn't gel with your Sky Daddy explanation, does it?
Fundamentally, it's not acquired, as explained numerous times. Certainly, in animals with more cerebral processing matter, there may well be elements of adaptive learning formed as experiences that aid them in later repetitions, and in other organisms you might even see this passed down culturally, just as we teach our children, but the primary explanation is that it's genetic. You do realise that IS an adequate answer? If you don't accept that as an answer, your entire screed is problematic as that's what everyone will provide as an answer. Instead, you'd need to actually talk substantively about what DNA does and how it does it. Otherwise, you're just tilting at windmills.
asyncritus wrote:Further, it must be obvious to you that a journey of 7,800 miles poses an enormous threat to their survival.
Errr no. It's obvious to me that NOT doing the journey of 7800 miles poses a far more significant threat to its survival, because I am not interested in a single bird, but the population, the remainder of which are all eating their full and shagging with abandon in the targeted destination... unlike your platonic bird which decided it was all just too much bother.
asyncritus wrote:Whether the swallows fly entirely over water is not clear to me, but the godwit flies 7000 miles, and the plover flies 2,800 miles entirely over water, with no stopping points possible.
Explained to you in the past. Continental Drift. Ignoring it in 3...2...1.... BAM it's gone! Ahhh potentially-thought provoking challenge solved!
asyncritus wrote:Therefore those migrations at least were not undertaken bit by bit.
Continental Drift. Ignoring it in 3...2...1.... BAM it's gone! Ahhh potentially-thought provoking challenge solved!
asyncritus wrote: There were simply no places to stop.
Continental Drift. Ignoring it in 3...2...1.... BAM it's gone! Ahhh potentially-thought provoking challenge solved!
Birds nesting on clouds again, Async?
Async. I explained all this to you 2 or 3 years ago on RDF. Why is it you refuse to learn? Do you think God will be angry with you?
Morton's Demon writ large.