From: 69jpil69@gmail.com
On Wed, 9 Jul 2025 08:19:55 -0700, erik simpson
wrote:
>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-
f-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.
>>
>>>
>>>> That was pretty much my thought; while an exact "replay in
>>>> reverse" would be essentially impossible, as you say there
>>>> are multiple paths. All that would be required would be a
>>>> re-creation of function, not an exact "reboot".
>>>>
>>>> As has been pointed out several times, a re-start at the
>>>> original point would almost certainly (probability as close
>>>> to zero as can be imagined) *not* follow the identical path
>>>> resulting in the current species, but the same challenges
>>>> should result in something similar.
>>>
>>>
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