Its due to the Whales vs Sharks ancestry. Whales, being descended from land dwelling mammals, have a vertebrate that moves more efficiently up and down vs left and right. Though the closest living ancestor is a not very mobile Hippo, if you look at something like a cheetah running you'll get an idea of how the mammal spine moves which explains the tail's shape.
Also important is the tail is formed from two separate feet, which would morph with more ease into a horizontal plane then a vertical one.
well, I wished to write about the legs at first, but then I realised, that they have some artifacts of legs (sorry, can't find up the correct word rigt now) more in front of the body, don't they? So, the tail comes from the actuall tail of vertebrates, doesn't it?
Cis or trans? That's what matters.
The fish and whales while both vertebrates, evolved to swim at different times and via different evolutionary pathways - the evolution of their tails has solved the same problem in slightly different ways. In the same way that insects, bats and birds have evolved wings - they are all adapted to fly but the structure of the wings shows significant differences.
Last edited by Dougalbod on Thu Oct 29, 2009 11:36 am, edited 1 time in total.
Actually thinking about it your right... the front limbs (if that's an appropriate term) contains the ancestral bones, but the rear tail (Is it called a fluke?) does not and is an extension from the spine and therefore not derived from rear limbs... Still, I'm almost certain the spine movement is why it favored a horizontal to vertical plane.
From the little I know about whales, this sounds correct. All whales are believed to have evolved from Ambulocetus, a land dwelling mammal in the Eocene period. Whales today still have remnants of their hind legs which, don't quote me on this, I have heared are now only used during mating.
Don't mind me, just your average Biology student =)
Whales aren't just a different species. They are a different PHYLUM - which is an altogether different kettle of fish (ha ha!).
A shark is a genuine fish, a cartilaginous fish to be a little more exact. That means that it's skeleton is composed mainly of guess what? Cartilage.
That's distinct from other fishes which have bony skeletons, or don't have jaws.
Go here if you want more detail:
http://en.wikipedia.org/wiki/Template:B ... h_taxonomy
A whale, on the other hand, is NOT a fish. Don't feel bad about this, the greatest taxonomist of them all, Linnaeus, made the mistake of classifying whales with fish. It was an easy mistake to make, and he fell for it.
A whale is a MAMMAL. Like us.
However, the whales present major evolutionary problems. Their tails, like the dolphins', move up and down instead of from side to side. That requires ABSOLUTELY MAJOR changes in the musculature. How did that happen? Dunno.
But that's not all.
If the whales descend from a land animal (as Babinski says) like Pakicetus, you can begin to see the difficulties if you look at this reconstruction of Pakicetus:
which looks like a large fox.
How that could possibly become this:
is absolutely beyond me.
But it's not only size.
Whales, like all other mammals, are warm-blooded (which means their body temperatures remain constant), unlike fishes whose body temperatures vary with the water temperature.
Mammals produce young alive, and feed them on milk.
Now think about that for a moment.
Imagine a cow, which is warm blooded, having a calf, and then suckling it underwater! The moment the new-born calf opens it's mouth, it swallows a huge mouthful of seawater. How long do you think it will survive? Zero.
So what happens? Well, get this: the mother whale has a SPECIALLY DESIGNED nipple, which allows the calf to suckle underwater!!!! That didn't evolve - the species would have died out, while it was 'evolving'!
I can't find a picture of this special nipple, or I'd put it up for you. If anybody has ever seen one, please let me know.
But not only that.
Whales have been found nearly 2 MILES down - and came back alive. Have you any idea of the pressure their bodies withstand? Well, in the old foot/pound/second system, the pressure at any given point in a liquid is given by the formula
Pressure = depth in inches x density (of water) x 32
That works out to be
2(miles) X 5280 (feet) x 12 (inches) x 1 (density of water) x 32 pounds per square inch
= 405,504 lbs/sq inch.
That calculation is bound to be wrong - because it's been a long time since I did physics, but assuming it's 100 times too big, it's still 4,050 lb/sq inch.
Now how in heaven's name did the descendant of something like a fox become able to withstand that kind of pressure? A Los Angeles Class nuclear submarine can do it, because it has been designed to do so - but a fox???? You gotta be kidding me.
To my mind, one of the miracles of nature is how whales, dolphins and bats find their prey. (I have an article on the subject here:http://belligerentdesign-asyncritus.blogspot.com/2009/10/bats-flight-and-echolocation.html).
They use an echolocation system - which, get this, the US military is still trying to copy, so far is it superior to anything they've got, and you know how advanced they are!
I can't go into it here but do have a look at my article.
Hope all this helps.
Last edited by canalon on Thu Nov 19, 2009 11:07 pm, edited 1 time in total.
Reason: Remove self promoting useless link at the end...
So your main argument against evolution is that you cannot understand how it can have worked. I must admit that I have lots of problem following the math involved in relativity, but that is not a reason to ditch it altogether.
This is one of the most stupid and self centered argument I have ever seen. But admitting your stupidity that way takes balls, congrats Mister.
As for your answer it is correct up to
after that it is self admittedly stupid ramblings.
Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
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