Article

2006-11-06 Science & Technology

Japanese researchers find dolphin with 'remains of legs'

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Posted by anonymous5089 2006-11-06 06:30|| || Front Page|| [11130 views since 2007-05-07] Top

#1 Here I thought they'd found "remains of legs" in the thing's stomach.

Posted by Rob Crawford">Rob Crawford 2006-11-06 09:15|| http://www.kloognome.com/]">[http://www.kloognome.com/] 2006-11-06 09:15|| Front Page Top

#2 Maybe they're evolving to walk on land again. I welcome our new dolphin overlords.

Posted by Thoth 2006-11-06 10:42|| 2006-11-06 10:42|| Front Page Top

#3 One thing that has always puzzled me about this level of macro-evolution is this.

If a land animal survives on land with legs, what motivated it to move into an acquatic environment? After all, for evolution to make this large a change had to take a looooooong time. Did the animals with legs slowly move into a swamp, then a marsh, then a pond, then a ...... And what kept them in their neither fish nor foul state from being easy prey? At what point did it become advantageous to have fins, and how many generations did it take? Where are the fossil animals with legs that have prototype fins?

This sort of evolution seems to have way too many holes in it. And no, I'm NOT a creationist. I'm just comfortable with the idea that we don't know everything and probably never will.

Posted by AlanC">AlanC 2006-11-06 10:52|| 2006-11-06 10:52|| Front Page Top

#4 Major changes in ecosystems due to long term climate change. Having legs is great if there's a lot of dry land, less good if water levels rise and continents offer smaller habitats.

Add in a die-off of reptilian sea predators and then, a long time later, the rise of mammals. The niche for large sea predators is now open and attractive.

Posted by lotp 2006-11-06 10:58|| 2006-11-06 10:58|| Front Page Top

#5 The niche for large sea predators is now open and attractive.

Whalers?

Posted by Nimble Spemble 2006-11-06 11:21|| 2006-11-06 11:21|| Front Page Top

#6 Wonder about your webbed fingers that a monkey doesn't have?

Think H.Sapians spending a long safe time in the intertidal zone.

Lion comes - head to water
Shark comes - head to land

Hungry - dig a clam

Posted by 3dc 2006-11-06 11:25|| 2006-11-06 11:25|| Front Page Top

#7 One thing that has always puzzled me about this level of macro-evolution is this.

If a land animal survives on land with legs, what motivated it to move into an acquatic environment? After all, for evolution to make this large a change had to take a looooooong time. Did the animals with legs slowly move into a swamp, then a marsh, then a pond, then a ...... And what kept them in their neither fish nor foul state from being easy prey? At what point did it become advantageous to have fins?, and how many generations did it take? Where are the fossil animals with legs that have prototype fins?

This sort of evolution seems to have way too many holes in it. And no, I'm NOT a creationist. I'm just comfortable with the idea that we don't know everything and probably never will.

In the 50s

Posted by RD 2006-11-06 12:28|| 2006-11-06 12:28|| Front Page Top

#8 One thing to keep in mind on this ... on the macro view point you see things change like fins to legs, etc.

However, on the micro scale, a billion evolutions occur between legs and fins.

The key to this interplay of micro and macro, is to understand a change may occur that has no impact in current environment, but drastic changes later.

For example, human hemogloblin, has changes from other hemogloblin that allow less strong bonding of the oxygen in the heme group. This has the effect of allowing the oxygen to be given up to tissue much 'easier' than other hemogloblin.

Thus, our hemo is a bit over-clocked.

When this change occured, it may not have mattered at the outset. Many generations on it mattered drastically as it allows our warm-blooded bi-pedal nature an advantage over others (we can exchange oxygen more efficiently, thus can move faster and for longer, etc).

Anyway, the point is, from the macro scale a change of legs to fins or wahtever is not one single change. It is the accumulation of tons of other changes, some of which may be meaningless when the change occured but coupled with another express a major advantage or dis-advantage.

That is to say, the macro change doesn't just occur - it is the accumulation of hunders/thousands of other changes and they must be viewed together to pin 'that is when it became more advantagous to have legs'. This mapping is very complex and takes a lot of analysis.

Factor in that many genomes hang onto the 'old' stuff or things go dormant and it is verh hard to get a perfect picture.

Posted by bombay">bombay 2006-11-06 13:42|| 2006-11-06 13:42|| Front Page Top

#9 Bombay, lotp,

"When this change occured, it may not have mattered at the outset" hence the question.

If it did not matter why did it change and why did it prevail over the long term which was needed for the mutation to stabilize and become complete? This seems to be NOT survival of the fittest, but survival of the luckiest. Which, of course, confounds the idea that changes were a rational or logical response to external stimuli.
Climate change works on a MUCH shorter cycle than massive biological mutation, by the time a species mutated to take decreasing land into account, land would have been increasing.

RD roflmao!!!! (I always wanted a '59 Chevy)

Posted by AlanC">AlanC 2006-11-06 14:01|| 2006-11-06 14:01|| Front Page Top

#10 confounds the idea that changes were a rational or logical response to external stimuli.

Species do not make a 'rational' decision to evolve. As for survival of the luckiest, that is essentially what natural selection is. Being adapted to your environment increases your chances.

I'm tempted to say that your grasp of biology lacks opposable thumbs, but that would be an ad ~~hominem~~ hominid attack. heehee.

Posted by SteveS 2006-11-06 14:46|| 2006-11-06 14:46|| Front Page Top

#11 Alan,

A good question and the answer is exactly the interplay between micro and macro.

For example, why does a change progress if it doesn't offer instant advantage or disadvantage?

A change may occur on the micro for pure thermodynamic reasons. For example, a protien may incur a change in strucutre, which while not impacting the function of the protien allows it to assemble easier (i.e. takes a little less energy to build version A vs. B).

Thus a change at the micro level could set us up for a macro expression now or later. Say for example, another micro change for energy sake occurs, but now when the two changes are in play there is an expression at macro level - human hemoglobin can now perform 20% more efficient ... humans can now hunt better, their population grows.

Again, an example, not saying this is exactly what happened with hemoglobin. But your two micro thermodynamic changes resulted in a functional change to the protien which afforded an advantage and we're off to the races.

Again, the answer is the interplay between micro and macro. Steve has it exacly right, this occurs with no logic, it is a iterative trial and error process - hence evolution and not revolution!

Posted by bombay">bombay 2006-11-06 14:56|| 2006-11-06 14:56|| Front Page Top

#12 Oh yes, another thing to keep in mind these changes play out in parallel; not in serial.

It is not a change this, see what happens, make another change.

There are many 'threads' to track at once to chase down what is/has and could change!

Posted by bombay">bombay 2006-11-06 14:58|| 2006-11-06 14:58|| Front Page Top

#13 Japanese researchers find mutated dolphin with ~~'remains of legs'~~ extra fins.

Fixed it.

Posted by mcsegeek1 2006-11-06 15:02|| 2006-11-06 15:02|| Front Page Top

#14 Re: micro vs. macro:

it is a truism among serious breeders of purebred show dogs, horses etc. that many desireable traits at the anatomical level are the result of multiple genes interacting with one another and, we are finding, with the biochemical environment within which they are expressed as the fetus develops.

For instance, a "good front assembly" in a hunting dog -- i.e. one that suits it to working all day at a trot in brush -- can be described in terms of the proportional length of the various bones that make up the front legs, shoulders and chest assembly. Bone density comes into play as well, and the desireable proportions for a trotting breed like the spaniels and setters are quite different from those of the sighthounds, for instance.

Breeding is an art rather than a science in good part because even those individual elements of anatomy are each the product of multiple genes and other factors. Cattle breeders have developed indices of heritability for anatomical parts -- i.e., how easy/hard it is to "fix" a less than optimal front assembly in offspring by breeding to another animal whose front assembly is more desireable. Few traits have heritability of more than 50%, many are quite lower.

To make things more complex, it's not a simple matter of "gene present automatically leads to result in body". Many genes interact with one another in subtle ways, including by partially enabling or suppressing the expression of other genes when present in combinations. These partial interactions have been discovered to play a part in whether some genes actually result in certain inherited diseases showing up in a given animal, for instance. In one of my breeds, a dog that inherits two copies of the gene for a certain gradual blindness often does not in fact go blind despite living to an old age -- but his/her offspring might, if s/he inherits copies of that gene from both parents.

Bottom line up front: what you see (anatomy) is the result of very complex interactions of genes with genes and of genes and environment -- including the environment within the womb for mammals, the mother's nutritional status during gestation etc etc.

Posted by dog breeder 2006-11-06 15:22|| 2006-11-06 15:22|| Front Page Top

#15 "could be the remains of back legs"

Or not.

Coulda, shoulda, woulda, maybe - call me when you've got any actual, you know, FACTS.

Posted by Barbara Skolaut">Barbara Skolaut 2006-11-06 15:29|| http://ariellestjohndesigns.com/page/15bk1/Home_Page.html]">[http://ariellestjohndesigns.com/page/15bk1/Home_Page.html] 2006-11-06 15:29|| Front Page Top

#16 Exactly, and the list of etc, etc, etc is MASSIVE and not totally complete yet.

Bottom line though, a million things occur at micro long before expression at macro.

Posted by bombay">bombay 2006-11-06 15:29|| 2006-11-06 15:29|| Front Page Top

#17 I still think dolphins are enchanted humans.

Posted by Seafarious">Seafarious 2006-11-06 15:33|| 2006-11-06 15:33|| Front Page Top

#18 Steve S, I'm glad you believe in adding such brilliance to a discussion. Of course you may be offering yourself up as an example of this intermediate state, but I won't say that.

The logic about which I was speaking is cause vs effect. To use one of Darwin's examples, the bird with the bigger beak, did that come about because of the type of food available; or did was that a random mutation that happened to be good for that type of food?

I've never claimed to be a biologist, however, some of the evolution "facts" seem to be kind of short on a few steps in the process. Micro evolutionary mutations are one thing, having the entire sequence occuring sufficient to the macro level changes e.g. losing legs and gaining fins, needs to have some serious statistical study done based on time and random changes.

Despite the old saw, a thousand monkeys typing aren't going to produce Hamlet.

Posted by AlanC">AlanC 2006-11-06 15:43|| 2006-11-06 15:43|| Front Page Top

#19 providing further evidence ocean-dwelling mammals once lived on land.

I just saw this on The Simpsons.

Posted by tu3031 2006-11-06 15:51|| 2006-11-06 15:51|| Front Page Top

#20 Alan,

You are close :

'The bird with the big beak, did that come about because of food or a mutation'

Here's the problem, you are looking at this as a binary state. It was either the environment OR a mutation which confered big beaks.

In reality, it is BOTH that come into play.

The food that requires a big beak may not have been in play in the past. For example, there was little in the way of competition for food so enough to go around. Populations increase, food becomes more rare.

Some members of the population have a mutation which allows them to consume other sources. Only those with longer beaks can reach the other source.

In the past, there was no selective pressure on this, however due to population increases and some environmental changes there is now selective pressure.

Members which express longer beaks due to the mutation are now afforded an advantage and will likley move on; while members of the other line fade away.

Another example along same lines, a mutation occurs which allows the birds to digest (although not fully to potential) another type of plant. Currently food is plentiful so this mutation is not in play.

Enviromental conditions or population pressures begin to have their toll. Members that can partially digest the alternate food source can survive long enough to get past the 'dry spell' and pass the code along. The others fade away.

Thus, the two in play have both had impact.

Anyway, point is the equation is more like

past mutations + current mutations + gene interplay + current conditions + a whole lot more = story.

vs.

big beaks = because food was out of reach of small beaks

or

big beaks = because mutation occured.

The debate which you allude to occurs in the transition from micro to macro.

Posted by bombay">bombay 2006-11-06 16:22|| 2006-11-06 16:22|| Front Page Top

#21 God gave this dude the sport package. Thats all.

Posted by BrerRabbit 2006-11-06 16:48|| 2006-11-06 16:48|| Front Page Top

#22 AlanC: it might be instructive to look at other aquatic mammals, such as seals, otters, and beavers, as well as aquatic reptiles such as iquanas, crocodiles, and alligators. Alligators switch back and forth between land and water, but they're remarkably well adapted.

(I started to say "amphibious" but I was worried about confusion happening).

Anyway, I'll see y'all tomorrow; I'm heading home.

Posted by Abdominal Snowman 2006-11-06 17:10|| 2006-11-06 17:10|| Front Page Top

#23 ... and it was delicious.

Posted by DMFD 2006-11-06 17:45|| 2006-11-06 17:45|| Front Page Top

#24 RD roflmao!!!! (I always wanted a '59 Chevy)

Had one, a Biscayne (Cheap model, six Cylinder) the fins were supposed to be for high speed stability, pure horseshit, it wallowed like a round-bottomed steamer in a gale.

Posted by Redneck Jim 2006-11-06 19:51|| 2006-11-06 19:51|| Front Page Top

#25 One other factor no one has mentioned: sex appeal. First example is peacock tails: the males have them only because the females respond to bigger, fancier tails, which otherwise make the peacock less likely to survive. The second example is large breasts and buttocks, and a comparatively small waist, on the homo sapian female, which conveys no survival characteristic except that it makes her more desirable to the male of the species.

Posted by trailing wife 2006-11-06 19:54|| 2006-11-06 19:54|| Front Page Top

#26 Seafarious: (a Merman I Should Turn To Be) Hendrix

Posted by 3dc 2006-11-06 20:49|| 2006-11-06 20:49|| Front Page Top

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