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Preadaptations
- Thread starter Phronesis
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cyghost
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which preadaptions do you want me to respond to? those planned and incorporated by God when he spoke Life into existence or those that exists because a previous unused function suddenly becomes viable?
please specify in all honesty
please specify in all honesty
rwenzori
Honorary Master
This thread is not about preadaptations. Well, maybe a little bit, but only insofar as they demonstrate ( or you think they demonstrate ) the guiding hand of god in the processes of evolution. So lets call a farking spade a farking spade, stop the dissimulations, and move the thread out of Science into PD. We can recognize evangelism by "Intelligent Design" a mile off.
rwenzori
Honorary Master
So who then front-loaded evolution then? The FSM? He's a god, I suppose, but a bit of a feeble one, and he doesn't need to use evolution.
All your "mmmm"s and "something more"s - I cannot guess who you might be hinting at LOL!
See, there you go again... Going to stop anytime soon?
rwenzori
Honorary Master
I'll stop when you admit to your intentional design ( LOL ) to push your religious notions, and when this thread gets moved to the PD. What sort of idiots do you take us for? Mmmmmm?
Preadaptations are religious notions? I don't see you posting examples of them? Why not? That is the purpose of the thread...
I believe you guys are stuck symantically. Just because the terms is called "Preadaptation" doesn't mean there has been any planning or deliberate effort behind it from a higher being. Get back on track here...
Perhaps you should use the word "Exaptation"?
Perhaps you should use the word "Exaptation"?
Fair enough. However, I believe there is a subtle difference (even though Dennett might believe there is not).
Take the example of a feather. It can be argued that before it was used for flight (perhaps for keeping the animal warm) it was a preadaptation with regards to flight. Later on through co-option, it can be incorporated to be used in flight. Then it can be referred to as an exaptation.
Thus, it can be argued that preadaptations can be co-opted into exaptations. This thread focuses on preadaptations. Like in the example of the PAX6 gene that codes for the development of eyes, but was present way before the emergence of eyes. With regards to eyes then, Pax6 would be a preadaptation if it exists in an organism at the base of the eukaryotic tree without eyes before eyes existed. It was thus co-opted into signaling for the development of eyes (becoming an exaptation), even though it was present before the emergence of eyes.
Hence, the term preadaptation and not exaptation. I guess discussing how and why preadaptations become exaptations can also be discussed. However this does not detract from the examples of preadaptations given. However, if people feel there is not a difference between exaptations and preadaptations, that is fine, then there should be no objection in using the term "preadaptation".
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You are completely correct but some words lean themselves to misunderstandings or preconceptions, which in turn could disolve the purpose of meaningful discussion.
With regards to the religious snapper traps when discussing anything remotely to do with evolution let me give a different route for people wanting to discuss it who do believe in God as creator. The scientific research into evolution should be seen as a car. You can tinker with the car, turn the steering wheel, start the engine, take it apart and learn how it works without worrying who made the car. That is not so important yet, especially if there is no proof of an owner. Maybe the car was abandoned.
If you don't believe in evolution, there is no car for you there, just an empry parking space. Nothing to discuss. I don't think evolutions discounts the existence of a higher being, but this section is not for those discussions unless you have scientific proof that God exists or doesn't exist.
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cyghost
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You need to post more. That was beautifully said.
And we can apply this to "intentionality" "bio molecular machines" "agency" "front loaded" "message theory" "id"
etc etc etc
who wants to dissolve meaningful discussions? and certainly not on the science sub forum. We'll leave that for PD don't we? sad as that is.
hence my strenuous objection about continuing this in the science section. such obvious bias is redundant to any form of discourse, civilised or not.
You are right, I agree. The terms were discussed in the OP, thus any misunderstandings can only come from those who did not take the time to read the OP.
Back to business:
Tool kits for multicellularity before the emergence of multicellularity.
It is only until a few years ago that it was thought protein families involved in multicellularity were only present within the multicellular lineages. This old view is consistent with the view that evolution works by the slow accumulation of genes through chance and selection. This view is now a bit outdated.
Take a look at cadherins. Multicellular organisms require protein systems and molecules with adhesive properties in order to build multicellular systems. Cadherins is one such system. Another system for coordinating the multicellularity signaling system is protein tyrosine kinases.
In both these cases, the diversity of the these tool kits are greater in unicellular organisms (e.g. Monosiga Brevicollis) that their multicellular counterparts. In the case of tyrosine signaling, tyrosine kinase
signaling machinery in choanoflagellates (e.g. Monosiga Brevicollis) are even more diverse than those in the human counterparts and contain domains in combinations never before observed in the proteins from the multicellular lineage. This means that these shared protein domains that signal and control for multicellularity were present in the last common ancestor between mutlicellilar and unicellular organisms. Divergence from this group resulted in the independent use of the signaling machinery for multicellularity. These tool kits were then used for different purposes. E.g., while the TK signaling machinery is important for multicellularity in multicellular organisms, they appear to be important for bacterial prey capture in unicellular organisms.
Another interesting example is KNOX and BELL hox genes families that regulate stem formation in plants. In unicelllar alga, Chlamydomonas, their function is associated with regulation of gamete differentiation.
This data only further demonstrates that the old view of slow accumulation of genetic diversity through chance and selection is outdated, and shows that the genetic material necessary for multicellular transitions were present way before multicellularity emerged. And increase atmospheric oxygen pressure just unlocked the signaling capabilities of one of these tool kits.
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cyghost
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orly?
can we then please have your version of how and why the genetic diversity and a brief extract of your Nobel prize acceptance speech?And how do you think that happened hmmm?
Yes, it is just a plain fact that tool kits necessary for body plans, multi cullularity, eyes etc. were present before they emerged. Heck read about it if you don't believe me. It is not like body plans emerged as a result of a slow accumulation of genetic data to code for it. The data was there before it emerged. Where did it come from? Gee, is that part of the discussion now? Inevitable emergence and development through time sounds plausible after looking at the data don't you agree?
It was probably inevitable? If you replay time, I think it should happen again
. You?
rwenzori
Honorary Master
One assumes the red bit is sarcasm, given the blue bit.
Let us just verify what we are on about:
I fail to see how the slow accumulation of genetic material is incompatible with that definition. If, of course, you have an alternative explanation let's hear it. If it involves god, then at least you will be bringing your true purpose ( dare I say "intention" ) into the open, and we can move this into the PD section.
Purpose of the thread:
The genomes of various ancient organisms have been sequenced and it is interesting to view the presence of several preadaptations in the genomes of these creatures. The purpose of this thread is to highlight several of these interesting findings. If anyone come across any interesting findings, post it here.
Examples include:
Genes for nervous system cells before nervous systems emerged
Tool kits for multi cellularity before multicellularity emerged
Genes for the development of eyes before the emergence of eyes. This also resulted in the repeated emergence of eyes in various phyla.
Tool kits for body plans before the emergence of body plans. This resulted in the repeated emergence of various types of body plans.
How these tool kits and genes emerged before being repeatedly co-opted into various functions is irrelevant to the discussion. What is important is that these preadaptations happened and provide crucial knowledge in how they shaped future evolutionary trajectories. They may have emerged through chance, selection, self-organization, etc. Your repeated intention to drag this thread into PD is obvious. If you are unable to contribute, rather keep quite
.
rwenzori
Honorary Master
Hardly irrelevant - their origin is implied in the prefix "pre-" and is of course of interest and relevance. I am glad that you in any event do not mention anything supernatural or imaginary in your list of alternatives.
Only if people do not read the OP. Did you? Does not look like it since you felt the need to post the exact link that was posted in the OP to describe preadaptations. Be honest, did you read the OP before you posted this?
rwenzori
Honorary Master
Not that your bleating is particularly relevant, but, while you might have linked, you did not quote the bit about "inherited from an ancestor" in your OP. Since you are such an ace at quote-mining, I must assume the omission was "intentional". I wonder why? mmmmmmm??