ElShamah - Reason & Science: Defending ID and the Christian Worldview
Would you like to react to this message? Create an account in a few clicks or log in to continue.
ElShamah - Reason & Science: Defending ID and the Christian Worldview

Otangelo Grasso: This is my library, where I collect information and present arguments developed by myself that lead, in my view, to the Christian faith, creationism, and Intelligent Design as the best explanation for the origin of the physical world.

You are not connected. Please login or register

Ultrafast Movements in Snapping Shrimp Claws: By saltational evolution, or design?

Go down  Message [Page 1 of 1]



Ultrafast Movements in Snapping Shrimp Claws: By saltational evolution, or design?

The puzzling origin of the snapping claws of pistol shrimps provides a good example of evolutionary storytelling.



Snapping shrimp, also known as pistol shrimp or alpheid shrimp, compete with whales for the title of loudest animal in the ocean. To make noise, snapping shrimp are able to close their claws incredibly fast, which shoots a stream of water so quickly that new water from above doesn’t have time to replace it, creating a vacuum bubble (called a cavitation bubble). The collapse of that bubble causes an audible snap, which sends out shock waves that are powerful enough to kill small fish that the shrimp can then eat.

But how have these shrimp got this remarkable ability? It seems improbable that evolution would even allow this to occur, and yet, the powerful snap has evolved independently in two different shrimp families. All we’ve known until now is the endpoint of these super snapping claws. “What we now know is that a series of small changes in form led to these big functional changes.”

My comment:  The observation of convergence or the same biological feature in different creatures in the phylogenetic tree is evidence against evolution, and evidence for creation. 1

Stephen J. Gould, Wonderful Life: The Burgess Shale and the Nature of History (New York, NY: W.W. Norton & Company, 1989),
“…No finale can be specified at the start, none would ever occur a second time in the same way, because any pathway proceeds through thousands of improbable stages. Alter any early event, ever so slightly, and without apparent importance at the time, and evolution cascades into a radically different channel.

Paleontologist J. William Schopf, one of the world’s leading authorities on early life on Earth, has made this very point in the book Life’s Origin.
Because biochemical systems comprise many intricately interlinked pieces, any particular full-blown system can only arise once…Since any complete biochemical system is far too elaborate to have evolved more than once in the history of life, it is safe to assume that microbes of the primal LCA cell line had the same traits that characterize all its present-day descendants.

Shrimp (infraorder Caridea) are incredibly diverse. There are many families and species of them, including two families of shrimp with the ability to snap. Researchers studied 114 species of shrimp from 19 families located all over the world and looked closely at the claw joints to see how they worked. What they found was that there are only very subtle differences between the claws of snapping and non-snapping shrimp

My comment: It is remarkable, that snapping shrimps are found in the fossil record, and there is no evidence of transitions whatsoever. They appear fully formed with their amazing ability.

Geology page: An adaptation 150 million years in the making January 3, 2018
Just how do snapping shrimp snap? This was the question plaguing scientists who set out to uncover the mysterious mechanisms producing big biology in tiny crustaceans. “All we’ve known until now is the endpoint of these super snapping claws,” said Rich Palmer, biological science professor at the University of Alberta and senior author on a new study on snapping shrimp claws.  “What we now know is that a series of small changes in form led to these big functional changes, which essentially allow these shrimp the ability to break water, or snap.”

My comment: They don't know that. They are putting the horse in front of the cart. Snapping shrimps appear fully formed in the fossil record, with no precursors.

Matúš Hyžný Comprehensive analysis and reinterpretation of Cenozoic mesofossils reveals ancient origin of the snapping claw of alpheid shrimps  22 June 2017
Alpheid snapping shrimps (Decapoda: Caridea: Alpheidae) constitute one of the model groups for inferences aimed at understanding the evolution of complex structural, behavioural, and ecological traits among benthic marine invertebrates. Despite being a super-diverse taxon with a broad geographical distribution, the alpheid fossil record is still poorly known. However, data presented herein show that the strongly calcified fingertips of alpheid snapping claws are not uncommon in the fossil record and should be considered a novel type of mesofossil. The Cenozoic remains analysed here represent a compelling structural match with extant species of Alpheus. Based on the presence of several distinct snapping claw-fingertip morphotypes, the major radiation of Alpheus lineages is estimated to have occurred as early as 18 mya. In addition, the oldest fossil record of alpheids in general can now be confirmed for the Late Oligocene (27–28 mya), thus providing a novel minimum age for the entire group as well as the first reliable calibration point for deep phylogenetic inferences.

Daniel Lima First evidence of fossil snapping shrimps (Alpheidae) in the Neotropical region, with a checklist of the fossil caridean shrimps from the Cenozoic 26 July 2020
Dactylar and pollex 34 fingertips of snapping shrimps have been recorded by several authors from numerous 35 Cenozoic deposits, ranging from late Oligocene (Chattian, 27–28 Ma) to late 36 Pleistocene (Tarantian, 117–126 ka)

As with many morphological phylogenetic analyses of this scale, uncertainties remain. Many morphological features of alpheid shrimp exhibit parallel evolution. The causes of parallel preadaptation are presumably similar to those of parallel evolution, although debate continues over what these might be.

Tomonari Kaji Parallel Saltational Evolution of Ultrafast Movements in Snapping Shrimp Claws JANUARY 08, 2018
How do stunning functional innovations evolve from unspecialized progenitors? This puzzle is particularly acute for ultrafast movements of appendages in arthropods as diverse as shrimps, stomatopods, insects, and spiders. For example, the spectacular snapping claws of alpheid shrimps close so fast (∼0.5 ms) that jetted water creates a cavitation bubble and an immensely powerful snap upon bubble collapse. Such extreme movements depend on
(1) an energy-storage mechanism (e.g., some kind of spring) and 
(2) a latching mechanism to release stored energy quickly. 

Clearly, rapid claw closure must have evolved before the ability to snap, but its evolutionary origins are unknown. Unearthing the functional mechanics of transitional stages is therefore essential to understand how such radical novel abilities arise. We reconstructed the evolutionary history of shrimp claw form and function by sampling 114 species from 19 families, including two unrelated families within which snapping evolved independently (Alpheidae and Palaemonidae). Our comparative analyses, using high-speed video revealed a previously unrecognized “slip joint” in non-snapping shrimp claws. This slip joint facilitated the parallel evolution of a novel energy-storage and cocking mechanism—a torque-reversal joint—an apparent precondition for snapping. Remarkably, these key functional transitions between ancestral (simple pinching) and derived (snapping) claws were achieved by minute differences in joint structure. Therefore, subtle changes in form appear to have facilitated wholly novel functional change in a saltational manner.

Ultrafast closure of alpheid shrimp snapping claws is remarkable. Water is jetted so quickly that it “tears apart,” creating a cavitation bubble that releases immense energy upon implosion, including a powerful snap, and momentary extreme heat (>5,000°K) and light. This key innovation facilitated an explosive diversification (>80% of at least 600 alpheid species snap), presumably because snapping has so many functions: defense, predation, excavation, and possibly communication. Although such an extreme ability might seem highly improbable, snapping claws have evolved independently in two unrelated shrimp families (Alpheidae and Palaemonidae) and one amphipod genus.
Snapping claws pose a significant evolutionary puzzle: either a claw closes fast enough to create a cavitation bubble or it does not. Herein lies the fundamental conundrum: what changes in claw form amplified water jetting to speeds high enough to cross the cavitation threshold? Concurrently, we also tested whether stepwise functional change depends on stepwise morphological change.

My comment: The paper goes on with evolutionary storytelling, to conclude with guess work, using the words in their conclusion: most likely, appears to have, suggesting, can yield, could help explain, etc. to conclude that the big hero on the block, evolution, explains it all. Really??!!

Calvin Smith Pistol packing … Shrimp?! Watch out for this little guy! 17 April 2012
Not only are these shrimp armed and dangerous, they are also a rowdy bunch (“ … the shrimps’ snapping is the dominant source of background noise in the shallow ocean”1). They can easily compete with 40 ton heavyweights like whales in terms of ability to create noise. In colonies they can interfere with submarine sonar; “When colonies of the shrimp snap their claws, the cacophony is so intense submarines can take advantage of it to hide from sonar.”2 (This problem was first discovered in WW II because these creatures made it hard to detect hostile submarines!) Not only are the ‘gunshots’ used to attack, they are apparently used for communication as well.

The pistol shrimp’s claw is an extremely specialized construct that needs precision design in order to function. Of the millions of random mutations that might occur that would change the shape of a claw (a bump, indentation or protrusion of some sort?) there would be precious few that would have been ‘on the way’ to becoming a ‘sonic gun’ variant. Granting that evolutionists admit that beneficial mutations are rare, the point is; “What survival benefit would those small shape changes have conferred to the shrimp on the way to becoming a sonic claw?”

 Ultrafast Movements in Snapping Shrimp Claws: By saltational evolution, or design?  Fx1_lrg


1. https://reasonandscience.catsboard.com/t2014-convergence-another-problem-for-evolution


Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum