Uncommon Descent Serving The Intelligent Design Community

Three diverse animals independently arrived at maximal fin speed solution

Share
Facebook
Twitter
LinkedIn
Flipboard
Print
Email

From ScienceDaily:

Moving one’s body rapidly through water is a key to existence for many species. The Persian carpet flatworm, the cuttlefish and the black ghost knifefish look nothing like each other — their last common ancestor lived 550 million years ago, before the Cambrian period — a new study uses computer simulations, a robotic fish and video footage of real fish to show that all three aquatic creatures have evolved to swim using the same mechanical motion.

These three animals are part of a very diverse group of aquatic animals — both vertebrate and invertebrate — that independently arrived at the same solution of how to use their fins to maximize speed. And, remarkably, this so-called “convergent” evolution happened at least eight times across three different phyla, or animal groups, supporting the belief that necessity played a larger role than chance in developing this trait. The findings could help scientists better understand evolution as well as help pave the way for highly agile underwater vehicles.

“Chance does play a role in these animals — they don’t all adhere exactly to the optimal number 20 — but there is a point where variability can become deadly, that swimming with the wrong mechanics means you waste energy and won’t survive,” MacIver said. “The ratio of 20 is best.”More.

 

===============================================

Examples of animals evolving similar traits despite the absence of that trait in the last common ancestor, such as the wing and camera-type lens eye in vertebrates and invertebrates, are called cases of convergent evolution. – Rahul Bale et al.

===============================================

Here’s the abstract:

Examples of animals evolving similar traits despite the absence of that trait in the last common ancestor, such as the wing and camera-type lens eye in vertebrates and invertebrates, are called cases of convergent evolution. Instances of convergent evolution of locomotory patterns that quantitatively agree with the mechanically optimal solution are very rare. Here, we show that, with respect to a very diverse group of aquatic animals, a mechanically optimal method of swimming with elongated fins has evolved independently at least eight times in both vertebrate and invertebrate swimmers across three different phyla. Specifically, if we take the length of an undulation along an animal’s fin during swimming and divide it by the mean amplitude of undulations along the fin length, the result is consistently around twenty. We call this value the optimal specific wavelength (OSW). We show that the OSW maximizes the force generated by the body, which also maximizes swimming speed. We hypothesize a mechanical basis for this optimality and suggest reasons for its repeated emergence through evolution. Open access – Rahul Bale, Izaak D. Neveln, Amneet Pal Singh Bhalla, Malcolm A. MacIver, Neelesh A. Patankar. Convergent Evolution of Mechanically Optimal Locomotion in Aquatic Invertebrates and Vertebrates. PLOS Biology, 2015; 13 (4): e1002123 DOI: 10.1371/journal.pbio.1002123

So not only did life forms have to solve a special problem of  rapid locomotion, different ones had to solve it a number of times, with few if any hints from their ancestry. What are the informational probabilities of that? Wouldn’t the odds against this be greater than against it happening just once?

Follow UD News at Twitter!

Comments
"Why no green fur in Nature? Plenty of forest dwellers." Because most predators don't see color the way humans do. And many animals' vision is optimized for low light levels which affects the ratio of rods and cones so they don't see color well anyway. http://www.mexicanwolves.org/index.php/news/226/51/Did-You-Know/d,News2 http://www.livescience.com/40460-images-cat-versus-human-vision.htmlJim Smith
May 8, 2015
May
05
May
8
08
2015
07:54 AM
7
07
54
AM
PDT
Querius:
The problem with a label is that one can become dismissive as in “Oh that’s just an example of common convergent evolution.”
The entire Darwinist narrative is like that. It's all crap on the face of it.Mapou
May 2, 2015
May
05
May
2
02
2015
01:52 AM
1
01
52
AM
PDT
Collin @ 56 noted
That seems like what convergent evolution is. It’s just a label, not an explanation.
Well said! The problem with a label is that one can become dismissive as in "Oh that's just an example of common convergent evolution." -QQuerius
May 1, 2015
May
05
May
1
01
2015
11:23 PM
11
11
23
PM
PDT
Green Algae, Green Fish, Green Amphibians, Green Reptiles, Green Birds. But Mammals are different. We're special. Uncommon Descent. Blonde, Brunette, Redhead Going Grey to White is cool too. Santa. Good Design. Wait, who am I kidding - great design.ppolish
May 1, 2015
May
05
May
1
01
2015
07:48 PM
7
07
48
PM
PDT
Aurelio Smith: They have designed the (hair of) the sloth to be their perfect environment. The sloth's hair actually has special grooves which house the algae.Zachriel
May 1, 2015
May
05
May
1
01
2015
06:40 PM
6
06
40
PM
PDT
So the best nature can do is algae on a sloth for the appearance of green fur? Hermit crabs don't need their own hard shell, they formed a symbiosis with discarded shells that fit. ;)Joe
May 1, 2015
May
05
May
1
01
2015
04:06 PM
4
04
06
PM
PDT
I got my degree in psychology. when I took my history of psychology class, I learned that the field of psychology went through a stage where psychologists were calling everything "instincts." Like the mating instinct, the preservation instinct and even the death instinct. Psychologists finally realized that they weren't explaining anything, they were just naming things. Then they set out to explain why these apparent instincts exist rather than just labeling them. That seems like what convergent evolution is. It's just a label, not an explanation.Collin
May 1, 2015
May
05
May
1
01
2015
04:00 PM
4
04
00
PM
PDT
ppolish: Or try to explain why evolution can’t do green fur:) We have provided the scientific studies concerning sloth/algae symbiosis. Reading them is up to you, though.Zachriel
May 1, 2015
May
05
May
1
01
2015
12:41 PM
12
12
41
PM
PDT
58ish = old Darwinist fool. LOLMapou
May 1, 2015
May
05
May
1
01
2015
10:57 AM
10
10
57
AM
PDT
58ishJoe
May 1, 2015
May
05
May
1
01
2015
10:43 AM
10
10
43
AM
PDT
How old are you, Zachriel?Mapou
May 1, 2015
May
05
May
1
01
2015
10:25 AM
10
10
25
AM
PDT
Symbiosis with algae and mutualism with moths? Oh, what a tangled web we weave: When first we practise to deceive! Or try to explain why evolution can't do green fur:)ppolish
May 1, 2015
May
05
May
1
01
2015
10:14 AM
10
10
14
AM
PDT
The mutations in Lenski's experiment were "apparently random" because we have no idea what is really going on inside of a cell. Lenski's is a good example of "built-in responses to environmental cues".Joe
May 1, 2015
May
05
May
1
01
2015
10:08 AM
10
10
08
AM
PDT
ppolish: What is the “symbiotic relationship” We already provided genomic support. Returning to the ground has to do with mutualism with moths. Try this review article, Pauli et al., A syndrome of mutualism reinforces the lifestyle of a sloth, Proceedings B of the Royal Society 2014. Mapou: Lenski has demonstrated nothing other than the pre-designed adaptive ability of E. coli. The mutations involved were apparently random, and even then, some available adaptations weren't found by some lineages. The results are consistent with evolutionary processes. Mapou: One of the obvious fallacies of evolution is that the species that have the most prolific reproduction rate are the least evolved species. Rapid reproduction is just one of many evolutionary strategies. Termites seem to be doing fine with a much slower reproductive rate. Mapou: Adapted E. coli is still E. coli, not some new species. Lack of aerobic citrate usage is generally considered a defining characteristic of E. coli. Lenski's experiment evolved bacteria capable of aerobic citrate usage.Zachriel
May 1, 2015
May
05
May
1
01
2015
09:41 AM
9
09
41
AM
PDT
Evolution is the religion of old fools. LOLMapou
May 1, 2015
May
05
May
1
01
2015
08:58 AM
8
08
58
AM
PDT
AS:
Louis, you dilute the force of the word “lie” by using it incorrectly and frequently. It is not enough to be wrong to be called a liar. The lie must be uttered in the full knowledge that the statement is wrong. In this particular case, I fully believe what I have written. Furthermore, Richard Lenski has demonstrated evolution in progress with his classic E. coli experiment.
A lie is a lie whether or not you believe it. People believe in lies all the time and you are one of them. And the more stupid people are, the more lies they believe in. It's called superstition. Lenski has demonstrated nothing other than the pre-designed adaptive ability of E. coli. Adapted E. coli is still E. coli, not some new species. One of the obvious fallacies of evolution is that the species that have the most prolific reproduction rate are the least evolved species. This is 100% ass-backwards. I, too, am willing to believe but I am Popperian through and through. Just show me. Don't tell me. Your word is worth less than nothing to me.Mapou
May 1, 2015
May
05
May
1
01
2015
08:56 AM
8
08
56
AM
PDT
Sloths are most often preyed upon when they take potty breaks on the ground. Brown ground. What is the "symbiotic relationship" Zachary? Algae covered sloths taste bad?ppolish
May 1, 2015
May
05
May
1
01
2015
08:50 AM
8
08
50
AM
PDT
I'm calling BS on the "symbiotic relationship" explanation Zachary. It's an infestation in both Polar Bear and Sloth.ppolish
May 1, 2015
May
05
May
1
01
2015
08:28 AM
8
08
28
AM
PDT
ppolish: And Polar Bears? Asked an answered. Polar bear fur doesn’t normally harbor significant algae. That’s more common in zoos in moist climates. Your video is of polar bears in a zoo in Singapore, not exactly their natural environment.Zachriel
May 1, 2015
May
05
May
1
01
2015
08:22 AM
8
08
22
AM
PDT
"Sloths have formed a symbiotic relationship with algae to provide them camouflage" How convenient lol. And Polar Bears? One moist mammal's "symbiotic relationship" is another moist mammal's nuisance.ppolish
May 1, 2015
May
05
May
1
01
2015
08:13 AM
8
08
13
AM
PDT
Aurelio is confused. First there isn't any evidence for its claim that the environment drives evolution and Lenski has demonstrated that evolutionary processes are severely limited. Lenski's experiment supports baraminology, Aurelio.Joe
May 1, 2015
May
05
May
1
01
2015
08:05 AM
8
08
05
AM
PDT
Aurelio and Zachriel are the low-hanging fruit.Joe
May 1, 2015
May
05
May
1
01
2015
08:03 AM
8
08
03
AM
PDT
Zachriel:
Evolution is limited to modifications of existing structures.
Which is why it cannot make eukaryotes from populations of prokaryotes. There isn't anything you can do to a prokaryote to yield a eukaryote. It is close to a total redesign.Joe
May 1, 2015
May
05
May
1
01
2015
08:01 AM
8
08
01
AM
PDT
ppolish: Why can’t Evolution “Go Green” when it comes to fur? Evolution is limited to modifications of existing structures. Otherwise, Iraqi children would have Kevlar skin. Mammals have two types of melanin which are used for fur color; eumelanin and pheomelanin. Mixtures of these two pigments can create camouflage suitable for most environments, especially as most mammals live on the ground, and most mammals have limited color vision. http://www.onekind.org/uploads/a-z/a_zLeopard.jpg Sloths have formed a symbiotic relationship with algae to provide them camouflage. One species, Trichophilus welckeri, is passed from mother to child, is common in all sloth populations, but found in no other environment. See Suutari et al., Molecular evidence for a diverse green algal community growing in the hair of sloths and a specific association with Trichophilus welckeri (Chlorophyta, Ulvophyceae), BMC Evolutionary Biology 2010. The polar bear doesn't normally harbor significant algae. That's more common in zoos in moist climates.Zachriel
May 1, 2015
May
05
May
1
01
2015
07:57 AM
7
07
57
AM
PDT
Why can't Evolution "Go Green" when it comes to fur? http://en.m.wikipedia.org/wiki/Red_fox What is stopping evolution from such an obvious adaptation? Yep, Design. Design Null Hypothesis = Design can eliminate an obviously helpful adaptation.ppolish
May 1, 2015
May
05
May
1
01
2015
07:46 AM
7
07
46
AM
PDT
Same green algae on polar bears. Does the "just so" sloth story apply to Polar Bears? http://io9.com/5959012/the-biggest-myth-about-polar-bear-fur-and-the-weirdest-truthppolish
May 1, 2015
May
05
May
1
01
2015
06:53 AM
6
06
53
AM
PDT
Unguided evolution can't account for sloths nor fur...Joe
May 1, 2015
May
05
May
1
01
2015
03:22 AM
3
03
22
AM
PDT
That's not green fur, AS, that's green algae living in the fur. Sorry, there is a design rule against green fur. No amount of Evo change will give one green fur. Green skin and green feathers are workable, but not fur. Why no green fur? There is a physics/math/design rule that says no. Design usually drives "just so", but this time it prohibits it. Sorry Evo, can't go there.ppolish
May 1, 2015
May
05
May
1
01
2015
01:27 AM
1
01
27
AM
PDT
Environmental change drives evolutionary change.
This is a bold faced lie because it has never been demonstrated and can never be. Besides, there is no need for it. Environmental change simply drives adaptation. Adaptation does not need Darwinism. It needs intelligent, predictive planning, designing and engineering.Mapou
May 1, 2015
May
05
May
1
01
2015
12:15 AM
12
12
15
AM
PDT
The design kit for fur/feather coloration IS very amazing, goodusername. Much more amazing than "dark polar bears get eaten" and only white remain. Although I don't think white is a color artic mammals and birds even see. Why no green fur in Nature? Plenty of forest dwellers.ppolish
April 30, 2015
April
04
Apr
30
30
2015
09:54 PM
9
09
54
PM
PDT
1 2

Leave a Reply