Why would the dolphin evolve on land, then return to the sea?

Question

Why would the dolphin evolve on land, then return to the sea where it would have to re-evolve every feature that it had spent millions of years working on?

Answer 1

The very fact that dolphins live in the sea offers firm proof of evolution. The anatomy and breathing of dolphins is clearly not as advantageous as those of fishes or amphibians, yet, there they are.

Fish can swim faster than dolphins, who have to use a much more advanced brain and close teamwork to catch their prey. Fish don't need to surface every so often to take a breath of air.

Clearly, if dolphins are intelligently designed, God would have designed them to be more like fish.

However, the land-dwelling anscestors of dolphins had only natural selection as their designer, unless you (quite reasonably) consider that God created natural selection. Regardless, evolution bets on the cards that are dealt, and either builds upon it, or lets it go by the wayside.

There are a multitude of cave-dwelling species that clearly came from the same species that lived outside of caves. Why do these cave creatures still have eyes? Why is it that those cave creatures that originated in caves have no eyes at all, and those that migrated to caves not only lost the function of their eyes and their pigment, but still have some of the remnants of eyes? Why is it that those cave dwellers that came from light dwellers have a proportionate number of functional eyeparts as to the recentness that their species moved into lightless caves?

The fact is, eyesight has a metabolic cost attached to it. It goes well beyond atrophism. The genes actually change, and are passed on. For these genes to be passed on, they must have some sort of benefit. Two animals that live in the same environment, one with full vision and one without, both of whom live in an environment where sight has no value due to the darkness, have only a metabolic cost. That cost is sight. A sightless creature has less energy requirement than that of a sighted creature. Evolution explains this perfectly.
-Cave creatures have eyes that don't work because their ancestors had them, and not enough time has passed to allow that functuion to disappear completely.

What is creationism's explaination?
Why does God create a creature with eyes that will never need them?

What is Intelligent Design's explaination?
Why would an Intelligent Designer design a creature with eyes that don't function, for an environment where sight is not only useless, but a detriment (due to the metabolic cost)?

Likewise, a dolphin is far outperformed in the sea by even the fish they hunt. However, the ancestors of dolphins found themselves with certain mutations, and they, as a population, found a way to make it work for them. Dolphins have a definite disadvantage, being air-breathing mammals that live in the water, and lacking the ability to swim as fast as the fish they hunt, but they are much more intelligent than fish, and have techniques that they can use to hunt the faster, more agile, water breathing fish successfully. Who knows why their ancestors developed mutations that exchanged arms and legs for fins, and nostrils near their mouths for an airhole on top of their heads, but they did. If they hadn't had other mutations that allowed them to work with those mutations, they would have went extinct too. There are fossil whales with "blowholes that are exactly midway between the nostrils of land-dwelling mammals and modern whales. This would be expected, and such fossils are appropriately called transitional fossils (OHHHHH!!!! There's that dirty word that is nonexistant to creationists). There are many other transitions between modern whales and porpoises, and their ancestors, but that isn't important. What is important is to understand that evolution bets on the hand it is dealt, which beautifully explains why whales and dolphins and cave creatures still retain certain characteristics that would seemingly make them inept for aquatic life. It worked because if it hadn't worked, they would have died off, like their ancestors.

Of all the life that has ever existed on Planet Earth, 90% or more have gone extinct. The earth is at least 5 billion years old, despite creationist protesting. Hominids first appeared in the fossil record a mere 7 million years ago, and modern humans a mere 200,000 years ago, so it wasn't all our fault.

Why would an intelligent designer deserve respect and admiration for creating beasts that had less than a 10% chance of remaining alive as a species?
Why would a creator God create 90% of life just so it could go extinct?


I don't mean to denigrade anybody who thinks that God created us. However, evolution has many other proofs than this, and clearly, if God did create us and other life on earth, he must have done so by using evolution as a tool.

Is it so wrong to think such a thing?
I think not.

Even when I was a christian, I thought that God used evolution as His tool to make us. I'm an atheist now, and it wasn't evolution that changed my theology.

LESSON:
Don't be threatened by evolution or science. They can be reconciled. One just can't reconcile them if one has a strictly literal interpretation of the bible. In that case, one can only close their eyes to facts, or rule out theology.

I think it's a shame that YEC's force people to make such a choice. I hope you're not one of those.

El Chistoso

Answer 2

Why does anything evolve. As an adaptation to conditions. Think of how many mammalian carnivores there are on land. Were there any other mammals exploiting the niche that cetaceans have? Not likely. So the ancestors of cetaceans moved from the land into the waters, an unexploited niche. As a result over time cetaceans evolved to better exploit that niche. The ones that survived an reproduced being the ones that were better adapted to their environment.

Answer 3

Because there was an ecological niche available to it.


You are putting intelligence where there is none. Evolution does not plan, it does not have a target in place to aim for, it just happens.

Random mutations produce new generations that are better or worse suited to their environment, or better or worse suited to a different environment. If that creature is better suited then it produces more offspring and the mutation gets passed on more strongly to the next generation. And so on and so on. Little changes build up to produce big changes over longer periods.

But evolution does not care where the species came from, or where it might go. It might well make a species better adapted to a shrinking environment (polar bears for example) and the species goes extinct because it it too well adapted to an environment that disappears.

Answer 4

Step 1. Put down the hash pipe.

Step 2. Flush the stuff.

Step 3. Hit yourself in the head with a hammer

Follow steps for enlightenment.

Answer 5

Why would a fish evolve into an amphibian and go onto the land?

Answer 6

What the heck are ya talkin bout?!

You hopped up on goof balls or sumpin?

Answer 7

If only there was a Y!A category for asking biology questions...

Answer 8

Now, how on earth, do you know that?

Answer 9

Why not? If it was advantageous to do so? Use your brain, not your bible.