From: eastside.erik@gmail.com   
      
   On 7/9/25 6:14 AM, RonO wrote:   
   > On 7/9/2025 3:25 AM, jillery wrote:   
   >> On Tue, 08 Jul 2025 15:03:35 -0700, Bob Casanova    
   >> wrote:   
   >>   
   >>> On Tue, 8 Jul 2025 07:22:01 -0500, the following appeared in   
   >>> talk.origins, posted by RonO :   
   >>>   
   >>>> On 7/8/2025 4:36 AM, jillery wrote:   
   >>>>> On Mon, 07 Jul 2025 08:00:09 -0700, Bob Casanova    
   >>>>> wrote:   
   >>>>>   
   >>>>>> On Mon, 7 Jul 2025 07:01:51 -0500, the following appeared in   
   >>>>>> talk.origins, posted by RonO :   
   >>>>>>   
   >>>>>>> On 7/6/2025 10:09 PM, Pro Plyd wrote:   
   >>>>>>>>   
   >>>>>>>> https://indiandefencereview.com/its-official-dolphins-and-orcas-have-   
   >>>>>>>> now-crossed-the-point-of-no-return-in-their-evolution-of-returning-to-   
   >>>>>>>> land-again/   
   >>>>>>>>   
   >>>>>>>> Dolphins and orcas, revered for their intelligence   
   >>>>>>>> and agility, have reached a pivotal point in their   
   >>>>>>>> evolutionary journey. New research has revealed   
   >>>>>>>> that these marine mammals, once land-dwellers, have   
   >>>>>>>> evolved to a stage where returning to life on land   
   >>>>>>>> is biologically impossible. A breakthrough study   
   >>>>>>>> underscores that after millions of years of   
   >>>>>>>> evolutionary change, dolphins and orcas are now   
   >>>>>>>> forever bound to the ocean.   
   >>>>>>>>   
   >>>>>>>> Published in Proceedings of the Royal Society B,   
   >>>>>>>> the study scrutinized over 5,600 mammal species   
   >>>>>>>> to understand how dolphins and orcas evolved from   
   >>>>>>>> semi-aquatic ancestors to fully marine life forms.   
   >>>>>>>> The research, led by Bruna Farina, a PhD candidate   
   >>>>>>>> at the University of Fribourg in Switzerland,   
   >>>>>>>> concludes that the transition from semi-aquatic to   
   >>>>>>>> fully aquatic is a one-way path. Once a species   
   >>>>>>>> makes this leap, its evolutionary direction becomes   
   >>>>>>>> irreversible.   
   >>>>>>>>   
   >>>>>>>> Farina’s team found that this transition occurred   
   >>>>>>>> millions of years ago when mammals returned to the   
   >>>>>>>> sea. Unlike their terrestrial predecessors, dolphins   
   >>>>>>>> and orcas cannot evolve back to a land-based   
   >>>>>>>> lifestyle. Their adaptations—such as specialized   
   >>>>>>>> limbs, unique diets, and reproductive systems—have   
   >>>>>>>> become so ingrained that reversing these traits is   
   >>>>>>>> no longer possible.   
   >>>>>>>> ...   
   >>>>>>>>   
   >>>>>>>> The paper is here   
   >>>>>>>>   
   >>>>>>>> https://royalsocietypublishing.org/doi/10.1098/rspb.2023.1099   
   >>>>>>>> Dollo meets Bergmann: morphological evolution in   
   >>>>>>>> secondary aquatic mammals   
   >>>>>>>>   
   >>>>>>> Never say never.  How did fish adapt to terrestrial life styles?   
   >>>>>>> Dolphins already have lungs.   
   >>>>>>>   
   >>>>>> The whole thing sounds to me like "We can't imagine how this   
   >>>>>> could be accomplished, so it can't; simply too many   
   >>>>>> simultaneous changes are required", an assertion more   
   >>>>>> familiar from evolution denialists than from (supposed)   
   >>>>>> scientists. I wonder if they think that cetaceans became   
   >>>>>> semiaquatic (not fully; they still can't breathe underwater)   
   >>>>>> in one fell swoop? And if not, why the same gradual process   
   >>>>>> won't work in reverse?   
   >>>>>   
   >>>>>   
   >>>>> It's a matter of probability.  Between random genetic events and   
   >>>>> random environmental events, it's almost impossible for any *exact*   
   >>>>> evolutionary pathway to be repeated.  It would be like a broken glass   
   >>>>> reassembling itself.   
   >>>>>   
   >>>>   
   >>>> What is stupid about the claim is that they do not acknowledge the   
   >>>> possiblity of a new path to terrestrial adaptation.  There is no reason   
   >>>> to limit how they might adapt to life on land.  They have a new   
   >>>> starting   
   >>>> point and have broken a lot of bridges to get to where they are, but   
   >>>> there are likely multiple paths back to living on land, especially,   
   >>>> just   
   >>>> back to an amphibian type life style.   
   >>   
   >>   
   >> It depends on which claim you mean.  A new path would not be a   
   >> violation of Dollo's Law:   
   >>   
   >>    
   >>   
   >> As I pointed out, it is practically impossible for aquatic mammals to   
   >> reverse the traits which make them aquatic and restore their ancestral   
   >> land forms.  However, as I also pointed out elsepost, tortoises became   
   >> secondarily land animals from ancestral aquatic forms.  So the claim   
   >> that aquatic mammals could not evolve back to a completely different   
   >> terrestrial form is also incorrect.  Just as with tortoises, these   
   >> newly evolved terrestrial forms would necessarily retain traits of   
   >> their aquatic past.  That's the point of Dollo's Law.   
   >   
   > My take is that they would not have to take the reverse path.  It is   
   > much more likely that they would evolve into a seal like terrestrial   
   > animal if we drove pinnipeds to extinction and left that niche open.   
   > They would not go back to a lunging croc like animal like ambulocetus.   
   > Further terrestrial evolution would depend on what niche was open that   
   > they could exploit.   
   >   
   >>   
      
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