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.

[Allen In Texas Hill Country]

definition of life itself

---

Too easy. First, we take the sun. Its nothing more than a chemical engine. Extrapolating,,, life is the same thing except a little more elaborate (although not so grandiose) so one might call it a chemical computer that has sentient capabilities. But we have to be careful because we are applying our pitiful standards that may inadequately define sentient.

[Southack]

"Why do you make this claim? It's not in the original paper. If you wish to argue with yourself, feel free to do so."

You've failed to grasp the significance of what has been suggested by the article for this thread.

The article notes that two widely separated species have remarkably similar, perhaps even identical, muscles and tendons.

Further scientific examination of the shark and tuna genomes will reveal just how similar those muscles and tendons are (in their genetic instruction set).

This examination of shark and tuna genomes will then tell us, scientifically, if we have genetic code skipping or not (a potentially monumental scientific discovery).

[Michael_Michaelangelo]

First, we take the sun. Its nothing more than a chemical engine. Extrapolating,,, life is the same thing except a little more elaborate (although not so grandiose)

A little more elaborate?

I'd say so

[TN4Liberty]

Mutations cause divergence. Selection may cause convergence.

But selection also causes divergence doesn't it? Comparing the shark to the flounder yields an entirely different model.

[TN4Liberty]

Interesting that all these arguments assume no reality exists outside of the bounds of time. I imagine some felt at one time that all light was visible, too. I wonder if we we ever learn differently?

[Condorman]

Behold a Model A Ford pickup and a new Ford F150. The DESIGN has evolved but both had a DESIGNER! It would be foolish to assume that the pickup truck changed due to natural selection over 75 years.

Of course. Few people hold careers in vehicle husbandry. Yet there are selection processes at work. The most useful parts, the steering wheel comes to mind, are carried on into the next generation of vehicles. Unsafe construction and aesthetical abomination (the Gremlin notwithstanding) never makes it on the open market, or is quickly recalled. Some parts start out pretty well and then get improved--like drum to disk brakes.

It just so happens that in the case of automobiles, humans are substituting for the natural processes that 1) create variation and 2) select the features that survive.

One cannot conclude, however, that all processes creating change through successive generations is a product of directed intervention simply because you have identified one that is.

[Doctor Stochastic]

The shark and flounder come from different selection filters. Mutation acts like a general drift process. Selection acts as a filter.

[longshadow]

fishy placemarker

[arasina]

oh...I just realized the headline says FAST fish. I thought it said FAT fish. Now that would be interesting. :o)

[Doctor Stochastic]

I could have said FLAT fish, but I'm just floundering around.

[null and void]

You just said that for the halibut...

[Doctor Stochastic]

I did it on porpoise.

[Right Wing Professor]

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.

Actually it would, a great deal. But since you just made it up, I'm not so worried,

[Right Wing Professor]

This examination of shark and tuna genomes will then tell us, scientifically, if we have genetic code skipping or not (a potentially monumental scientific discovery).

Unfortunately, you're a bit late. The mitochondrial genomes of cartiliginous fishes have been done for some time, and they're just what we evil evos thought they would be. Sorry.

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=10051614

[Southack]

"Unfortunately, you're a bit late. The mitochondrial genomes of cartiliginous fishes have been done for some time, and they're just what we evil evos thought they would be. Sorry."

No, not late. Brand new, as in, so new that the article for this thread is crowing about the new conclusion.

What hasn't been examined yet, keyword: "yet", is whether the tuna and shark, which we now know share remarkably similar (perhaps even identical) tendons and muscles, likewise share identical DNA instruction set subroutines at any significant level.

If such identical programming code subroutines exist in tuna and sharks but do not exist in intermediate species in between, then we would have evidence of genetic code skipping that would falsify Evolutionary Theory.

We aren't there yet (that keyword again), but the article for this thread certainly shows that we are on a collision course for that potential scientific destination.

No doubt that open potential frightens you. You should therefore post some messages ridiculing the whole concept of examining literal base-pair sequences, and otherwise attempt to derail this quest. Who knows, it might even make you feel better; at least until the truth finally comes out...

[Right Wing Professor]

What hasn't been examined yet, keyword: "yet", is whether the tuna and shark, which we now know share remarkably similar (perhaps even identical) tendons and muscles, likewise share identical DNA instruction set subroutines at any significant level.

What part of 'mitochondrial DNA sequence' don't you understand?

[Condorman]

tuna is best eaten raw.

Preach on, my friend!

[Virginia-American]

My question was whether the scientific record of the genomes agreed with that faith.

I don't think the relevant DNA has been sequenced yet.

PS Although "faith" is a correct word to describe my thoughts here, I generally avoid using it because its other definition (religious faith) makes it easy to engage in the fallacy of equivocation.

What we're talking about here is a scientific prediction similar to thousands that have been made previously and were then later confirmed.

Since this has happened thousands of times, and the opposite (falsifying standard biology) has never happened, it seems like a pretty sure thing to bet on...

This is non-trivial. What we have here is a potential opportunity to examine the falsifiability of Evolutionary Theory.

True enough.

One such "falsifiability" would be direct evidence of specific DNA code completely skipping generations/species.

True. In fact there are a great many potential falsifications, some of which I listed here. The ones having to do with a pseudogene, transposon, etc being present in one species if it's present in two others are the same general idea.

PPS Sorry to take so long to reply, I could't FReep yesterday.

[Southack]

"PPS Sorry to take so long to reply, I could't FReep yesterday."

No problem. It's always pleasant to see reasoned debate, even it it takes time.