The Dolphin With Leftover Legs

ectotherm writes "Japanese scientists have captured a dolphin with vestigial legs. Evidence, it would seem, of a land-dwelling past and observable evolution." From the article: "Fishermen captured the four-finned dolphin alive off the coast of Wakayama prefecture (state) in western Japan on Oct. 28, and alerted the nearby Taiji Whaling Museum, according to museum director Katsuki Hayashi. Fossil remains show dolphins and whales were four-footed land animals about 50 million years ago and share the same common ancestor as hippos and deer. Scientists believe they later transitioned to an aquatic lifestyle and their hind limbs disappeared. Whale and dolphin fetuses also show signs of hind protrusions but these generally disappear before birth."

Another thing about Taiji, Japan

[Wills]

Taiji, Japan, is the site of the annual ritual dolphin massacre [earthisland.org] in which fishermen drive pods of dolphins into shallow coves and stab them with spears. You should see it. It is quite a sight. The sea water turns red with blood, and the air is filled with the extraordinary sounds of screaming dolphins (they literally seem to scream).

Re:I urge you to be insightful

[misanthrope101]

If natural selection were purely random, there would be no speciation. I've read several books by Dawkins, and Darwin's Origin of Species and randomness, though present, is not the driving factor. There is a random variation in the gene pool of any population, but the selection process, which favors or disfavors certain traits, is far from random, and drives change in the population by predisposing individuals with certain characteristics to be more likely to leave offspring than their competitors. Yes, the randomness is a component, in that if there were no variation there would be no foothold for the selection process, and thus no evolution. But randomness with no selection does not drive speciation, just as variation with no selection would also fail to drive it.

Re:Another thing about Taiji, Japan

[ettlz]

How do you know the grandparent poster was white, and what the hell does it have to do with the point raised?!

Re:Catholics believe in evolution, fossil record,

[mrand]

How is the world do fossils prove evolution? Where are the intermediate forms? What?! What do you mean there aren't any?

Of course there are - you just choose to put your head in the sand to ignore them. In fact, they are being discovered all the time... here's one just last week:
http://www.sciencedaily.com/upi/index.php?feed=Sci ence&article=UPI-1-20061102-12453000-bc-us-missing link.xml [sciencedaily.com]

Read on, if you dare to actually learn something:
http://www.skepticwiki.org/wiki/index.php/Intermed iate_Forms/ [skepticwiki.org]
http://en.wikipedia.org/wiki/List_of_transitional_ fossils/ [wikipedia.org]

Then stop saying the fossil record "proves" evolution because it doesn't. It proves there were dinosaurs. It doesn't prove evolution at all.

Actually, it doesn't even prove there were dinosaurs. All we know is that we find bones in the ground. The evidence indicates that there were dinosaurs. "Proof" in science is a misnomer.
http://www.newton.dep.anl.gov/newton/askasci/1993/ biology/bio039.htm/ [anl.gov]

It's really about evidence:
http://www.space.com/searchforlife/seti_devore_the ory_050303.html/ [space.com]

Note that I carefully avoided talk.origin's to keep you from claiming that that everyone refers you to the same source. The vast majority of the scientific community is in agreement about the vast majority of the conclusions drawn from the vast evidence that has been discovered thus far: evolution is a fact.

Re:You are the FIRST STUPID person i saw on slashd

[Jack9]

It's important to note that holding something sacred does not mean you do not kill and eat it. Native Americans held the buffalo sacred AND thought they were tasty.

Re:I urge you to be insightful

[Alsee]

But then you have dolfin A and human B but no in-between combinations (dolfin with stubbly legs)

The first and most important point is that the "dolphin with stubbly legs" *did* exist. We have the transitional fossils.

If you look back 10 or 15 million years, dolphins merge with whales. If you look back... if I recall correctly... about 50 million years, you find fossils of proto-whales with stubby legs. We have tons and tons of transitional fossils... such as whales with stubby legs... all over the entire fossil record.

Now, why doen't this particular in-between form still exist? Well thing about it. With stubby legs, it wouldn't be able to walk on land very well. And with stubby legs, it wouldn't be able to swim as well either. Dolphins are perfectly streamlined super fast swimmers. Having legs hanging off the sides would just be a drag in the water. They wouldn't be able to swim as fast to catch prey, and they would have to work harder and get more tired faster with the extra drag.

The "in-between" can simply die out. In some cases the "in-between" gets wiped out exactly because both "opposite ends" totally out-compete it.

Having wings and light bones makes you a great flier. Having four legs and strong bones makes you great on the ground. The two in-betweens aren't so good. Having 4 legs and light bones makes you fragile and vulnerable - regular ground animals have you totally beat. Having wings and heavy bones makes you a lousy flier that can't go very far or very fast and you get tired real fast - regular birds have you totally beat.

But notice that in both the dolphin example and the bird example while the in-between is "bad", it can still be better than one end if the other end does not exist. An "in-between" animal with wings and heavy bones may be a crappy flier, but it is still a better animal if if is the ONLY animal that can fly. If there are no good fliers around to out-compete you, then being a crappy flier is great. After you start flying, then you make other changes (light lighter bones) one step at a time to become more and more specialized to flight, and each improement out-competes and wipes out the previos "in-between" that was less specialized to flight. And the same goes with the initial development of dolphins. Being an "in-between" poor swimming mammal poorly adapated to living in the water is an advantage if there's lots of food available living in the water and it keeps you safe from non-swimming land predators and there's no good swimmer mammals to compete with you. And then over time the better swimmers (and ultimately the legless swimmers) out-compete and wipe out the "in-between" lousy swimmers.

When you branch off in a new direction, the leaders in that direction will often beat out and wipe out the less specialized "in-betweens", an on going competition to run and specialize in a single direction. An on going series of modifications to better specialize for life in the water or a life of flight or whatnot.

Of course not all kinds of "in-between" get actively eliminated like that. Sometimes you start with the "in-between" form, and then you simply have the population divided in two for some reason, and the two halves of the population simply drift apart over time. At some point they get so far apart that they simply cannot interbreed anymore, and then teher's no longer any way to create an "in-between" that has one new trait that first appeared in population and another new trait that first appeared in the other population.

One of the simplest and most common causes of this is when a species population gets split on two different land masses or split on opposite sides of a river or split by a mountain range or split on opposite sides of a desert ot anything else. I think you'll agree that humans living in different places drifted apart. The Japanese are different than the Irish are different than Eskimos are different than South Africans are different than Native Americans. You'll notice that those differen