Fast Fish Evolved Similar Design Separately

Science - Reuters ^ | 2004-05-05 | Patricia Reaney

[Junior]

LONDON (Reuters) - Great white sharks and tuna have a similar build for speed despite evolving separately for millions of years, scientists said Wednesday.

"Nature does it best in terms of design," said Jeanine Donley of the Scripps Institution of Oceanography in California. "It is amazing that they have developed to be so similar."

Lamnid sharks, which include mako and great whites, have been separated on the evolutionary tree from bony fishes, such as tuna, for over 400 million years. But the muscles and tendons that enable them to swim so fast are remarkably similar.

"Tunas and lamnid sharks have a body form that represents an extreme in biomechanical design for high-performance swimming," Donley said.

Lamnid sharks, which inhabit tropical to cold temperate waters in almost all seas, and tuna diverged from their ancestors in the design of their swimming features millions of years ago.

Their specialized features distinguish them from nearly all other fish and make them more like each other than their closest relatives.

The team, who reported their results in the science journal Nature, used video footage of sharks swimming in a tunnel and a device that measures muscle length during movement.

They believe it was evolutionary selection that allowed them to swim at high speed with a minimum of movement.

"There are body shapes...the roundness, the degree of tapering, even the tail shape, that you can calculate what would be approximately the most efficient for steady, straight swimming or burst swimming," Donley said.

"These two types of fish have this particular type of body shape which is ideal for hydromechanical efficiency."

Commenting on the research, Adam Summers of the University of California, Irvine, said scientists have been speculating on the similarities between tuna and mako sharks for decades.

"Understanding the mechanisms behind their locomotion could lead to high-speed autonomous underwater vehicles," he added.

[Trinity_Tx]

OK, I was confused by your first post.

No, tho... lol

What you say makes sense except that I don't see the conflict with evolution.

If you are not suggesting that each individual toss of any given coin is guided by God, but instead by the laws of physics, then how does this example contradict evolution?

If you were to record for observation and analysis the tosses of a thousand coins, there would be an awesome variation in the per second freeze-frames. You concede that God isn't designing those variations of each, or the influencing variables (wind, etc)... but the laws of physics are.

To me, it seems that in evolution, the variation in species is more parallel to those freeze-framed moments. They are results of the laws of biology combined with outside variables. (mutations/selection)

I think the "heads or tails" result is an artificial limitation and unfitting in the analogy.



Regarding the lack of variation in complex organs such as the eye, I would assume it is a result of common ancestry in those (now) totally species.

(But I'm still learning, so I could be totally wrong.)

[Trinity_Tx]

err.. make the above "totally different species"...

I shouldn't try to post while herding kiddoes to showers & bed. ~8|

[VadeRetro]

Nature does nothing -"nature" does not exist. "Nature" is a word used to describe the material part of all existence. There is no entity we can call "nature" that is supposedly doing anything. And "nothing" can't "design". Design is the product of intelligence, not chance. This statement in nonsense! Typical of scientists with materialistic presuppositions.

If you're asserting Design, the part in the middle makes the argument circular. Try calming down.

The statement "Nature does it best in terms of design" is an instance of anthropomorphic language being used to describe a non-anthropopmorphic process. The process involved is variation and natural selection. If that isn't what you call "design," it isn't what most people call "design." It's a convenient shorthand for the effect, a convergence upon some adaptation to environmental conditions, of variation and natural selection. Your rant, all based on semantics, is irrelevant to actual questions of historical process.

[Southack]

"Lamnid sharks, which include mako and great whites, have been separated on the evolutionary tree from bony fishes, such as tuna, for over 400 million years. But the muscles and tendons that enable them to swim so fast are remarkably similar."

That such "coincidences" are mathematically improbable doesn't trouble Evolutionists in the least.

That such obvious examples of DNA code re-use, in which genetic subroutines skip generations (and species) to be re-used...likewise doesn't bother Evolutionists.

But historians will laugh at such people in less than a century (especially if any laid off techie programmers make a move into the History field).

Code re-use is prima fascia evidence of Intelligent Intervention, by the way. Ask any software engineer.

[PatrickHenry]

The toss of a coin is quite determined, but we don't have the information to make accurate predictions. If we did, then we could. I'm not certain, but I think the results of a precisely designed mechanical coin-tossing machine would be easily determined.

I suspect the mechanisms that cause mutations are also determined (being physical and chemical) but it's all to complicated for us to predict which cell will mutate. In principle, however, if we had enough information, we could make good predictions. Or so it seems to me. Natural selection is also predictable, if you know exactly what's in the environment and what the living creatures are capable of. We can demonstrate this to a limited extent with bacteria in petri dishes. In the wild, of course, there are too many variables for us to handle. But in principle I think determinism rules the whole show, until you get to creatures like us with complex brains and free will.

Eyes all seem to rely on photo-sensitivity, but there is a great variety in such structures. Some simple creatures have only photosensitive spots. Complexity goes from there, all the way to us. And our eyes aren't that great. We're quite blind to most of the electro-magnetic spectrum. And we can't see at the micro-scopic level. Our eyes are just good enough to allow us to gather food, find mates, and survive. To do more we need to build instruments.

[Agamemnon]

I'll replace it with the word 'time'. It is available in infinite abundance.

Oh really? I challenge you to prove that.

[Trinity_Tx]

Thank you. : )

That's what I was thinking... the processes of both evolution and coin tosses are determined by laws of biology, chemistry and physics... While each can be purposefully influenced, whether by a coin-toss machine or genetic engineering, neither requires an intelligence to guide them.

Just trying to answer the "in the rush to divest God of any role in our affairs we have adopted a paradigm where action and purpose are ascribed to "chance" argument supported by a coin toss analogy.

[Doctor Stochastic]

If a coin is tossed high enough and is bounced on an elastic surface (so that the bounce is inelastic), it is impossible to compute the outcome from initial conditions that have any amount of uncertainty in measurement. Within any tiny but finite region of initial conditions, there are equally as many outcomes of heads as of tails.

Of course, I'm extrapolating the above from rigorous compuations for dice. I assume that coins are not less subject to the laws of physics than dice are.

[Dimensio]

That such obvious examples of DNA code re-use, in which genetic subroutines skip generations (and species) to be re-used...likewise doesn't bother Evolutionists.

You are confusing "similar structures" with "identical DNA". I understand your confusion. You're imagining that reality is how you want it to be, rather than how it is.

[Southack]

"You are confusing "similar structures" with "identical DNA". I understand your confusion. You're imagining that reality is how you want it to be, rather than how it is."

Is that so?! Are you claiming that Sharks and Tuna have no identical genetic routines in their DNA?

[Virginia-American]

Is that so?! Are you claiming that Sharks and Tuna have no identical genetic routines in their DNA?

Since shark and tuna diverged before either was as streamlined as they now are, standard biology predicts that the mutations responsible for the convergent evolution are different.

Some of the genes for things like cellular metabolism, histones, etc, (ie, things that they inherited from a common ancestor) may be quite similar.

[Southack]

"Since shark and tuna diverged before either was as streamlined as they now are, standard biology predicts that the mutations responsible for the convergent evolution are different."

Aye. That's the prediction. Now, what do their respective genomes say in reality?!

[Virginia-American]

Aye. That's the prediction. Now, what do their respective genomes say in reality?!

I don't know. Based on the record, I'd bet that this one is also true.

[TN4Liberty]

If we did, then we could. I'm not certain, but I think the results of a precisely designed mechanical coin-tossing machine would be easily determined.

Actually, chaos theory was developed in part to understand why this is not true. It goes back to sensitivity to initial conditions that is so great that unmeasureable differences in those initial conditions can produce widely divergent results.

I rarely post to these threads, but I read them often. While convergent evolution as described here is an interesting idea, how does one reconcile that convergence with the entire concept of divergence that most say is the engine that drives evolution? It seems conflicting to have a model that says that similar species "want" to become dissimilar, but dissimilar species "want" to become similar. (let's not argue the word "want" in this context).

[tm22721]

Design is the product of intelligence, not chance.

What if I deign to be wealthy and win the lottery ?

Yes I said 'deign' not 'design'.

BUMP

[Junior]

The dissimilar species are only converging with regard to body shape and muscle attachments in this case. This, of course, makes them move faster through the water to allow them to catch food (the shark) or escape being caught (the tuna).

We see remarkably similar processes in the morphology of the now extinct icthyosaurs and the modern dolphin.

[laredo44]

common Designer?

H2O?

[PatrickHenry]

While convergent evolution as described here is an interesting idea, how does one reconcile that convergence with the entire concept of divergence that most say is the engine that drives evolution?

Consider the pyramid. Here's one by the Aztecs, and then one by the Egyptians. Same general shape, right? Square bottom, 4 triangular sides, etc. Details vary, but you can recognize a pyramid when you see one:

Now then ... human cultures diverge. Yet architectural structures that have to overcome certain challenges (stones are heavy, building tall requires a wide base, etc.) all seem to converge. Why? You may: (1) assume it's because the laws of physics constrained the possibilities for any successful solution; or (2) you can stretch a bit and conjecture about ancient visitors from Uranus. It's up to you. For me, the simplest explanation is usually best.

[Doctor Stochastic]

Mutations cause divergence. Selection may cause convergence.

[Allen In Texas Hill Country]

I'll replace it with the word 'time'. It is available in infinite abundance.

---

Oh really? I challenge you to prove that.

---

Sorry 'bout that. Make that 'near infinite abundance'.

But the point is the same. Time created everything including all the Gods in the universe.