Whale question

[vargo]

Darwinism says there is always a way for the organism to go from A to B to C to D to E etc. without a point where no progress can be made. Why would it a land animal evolve into a whale when there are so many fish that were so better adapted to the water environment? Darwinism never predicts that something could NOT happen. Anything can evolve into anything else at any speed at any time. It does not FORBID anything?

[Darth Yoshi]

Simple. They live on coast, eat fish. Fish move into deeper water, or water gets deeper, or they end up on a tiny island. Regardless, they find themselves in a situation where they spend practically all their time in the water. As such, it becomes advantageous to grow fins.

No it doesn't. But only certain mutations are advantageous for any given environments. So the ones that aren't any good disappear.

[Akhlut]

Most fish aren't big or warm-blooded, either. Early whale ancestors would have greatly resembled seals and sealions. The reason that whale ancestors evolved into the whales and not stayed as seal-like creatures is because very few fish (in the modern era, only a three sharks, if I'm not mistaken: whale sharks, basking sharks, and megamouth sharks) occupied the niche that whales currently occupy (ie, big, open-ocean filter feeders). Some of the whale ancestors evolved toward the niche that dolphins occupy, too, which also happens to be filled only by sharks, really. And, even then, they fill slightly different niches: pack hunters for dolphins, solo hunters for sharks.

Darwinism says there is always a way for the organism to go from A to B to C to D to E etc. without a point where no progress can be made.

No, it doesn't. Evolutionary theory basically states that all organisms are under the pressure of natural selection. Those that succeed pass on their traits, those that fail do not pass on their traits. Organisms thus change and adapt to their environments. In no way does the theory say that organisms can evolve into any form with no restrictions. There are evolutionary dead ends due to lack of genetic diversity (dodos, dinosaurs, cheetahs, Asiatic lions).

Further, no vertebrates, fungi, or plants have colonized deep sea vents, and it is highly doubtful they ever could. So, that shows two whole kingdoms and one whole phylum being unable to exploit a niche and thus being unable to show "progress" toward that goal.

Darwinism never predicts that something could NOT happen. Anything can evolve into anything else at any speed at any time. It does not FORBID anything?

You need to take some college level biology courses. Go to the Talk Origins archive and read anything and everything about evolutionary theory there. You'll come out better for it, I swear.

[Akhlut]

Let me revise the "There are evolutionary dead ends due to lack of genetic diversity (dodos, dinosaurs, cheetahs, Asiatic lions)" statement into: "There are evolutionary dead ends due to lack of genetic diversity (dodos, pteradons, bird-hipped dinosaurs, cheetahs, Asiatic lions)."

[salm]

Let me revise the "There are evolutionary dead ends due to lack of genetic diversity (dodos, dinosaurs, cheetahs, Asiatic lions)" statement into: "There are evolutionary dead ends due to lack of genetic diversity (dodos, pteradons, bird-hipped dinosaurs, cheetahs, Asiatic lions)."

Cheetahs?

[Akhlut]

Yes, cheetahs. They went through a very small genetic bottleneck roughly 10,000 years (I could be off by several thousand years in either direction) and now all living cheetahs are almost clones of each other. There's very little genetic diversity among cheetahs alive today.

[Darth Raptor]

To understand the success of the whales, you need to rewind a few million years. The early Tertiary Period had massive power vacuums in almost every concievable niche. After all, this is the time directly following a disaster that wiped out some three quarters of life on Earth. A good rule of thumb in evolution is: "if you build it, they will come". Essentially, if there's a way to make a viable living out there, give them enough time and an organism will evolve to fill that niche.

So what we have in the Paleocene and Eocene is a marine ecology with huge gaping holes just begging to be filled. The plesiosaurs and mosasaurs are gone, and for reasons I don't completely understand fish and invertebrates are ill-equiped for these lifestyles. Thus, the torch passes to the mammals. So in simplistic terms the whales succeeded because the marine reptiles failed, the presense of large, air-breathing vertebrates in the world's oceans is hardly unprecedented.

I suppose this begs the question though of why fish are so slow to fill these niches that reptiles and mammals beat them to it...

[petesampras]

Whilst breathing air means the obvious disadvantage of having to return to the surface to breath - air contains far higher concentrations of oxygen. I'm not sure that this is such a major disadvantage for whales (at least compared with their advantages of fish), afterall Sperm whales can dive over a mile below the surface and go over an hour without breathing.

[Akhlut]

I suppose this begs the question though of why fish are so slow to fill these niches that reptiles and mammals beat them to it...

If I had to guess, it probably has to do with size. Most fish are fast-living animals and most of them survive and thrive due to a lifestyle of "live fast and die young." I'm not sure of exact proportions, either, but I'm pretty confident that most fish are semelparous (only breed once in a lifetime, but usually have a metric shitload of offspring) as opposed to iteroparous (breed many times in a lifetime, but with small numbers of offspring). The high fecundity that fish generally show is more difficult for larger ones to engage in, I'd think. Such a strategy for survival works well for small fish, but it doesn't make sense for a huge fish to engage in. Why expend so much energy to grow to whale size if your just gonna die after breeding once?

This is wholly speculation, though.

[Admiral Valdemar]

So whether you're an R- or K-species dictates whether you rule the waves or land or air? Hmm, seems somewhat applicable, though there are plenty of anomalies such as insects on land and so on.

[Akhlut]

So whether you're an R- or K-species dictates whether you rule the waves or land or air? Hmm, seems somewhat applicable, though there are plenty of anomalies such as insects on land and so on.

I'd say it determines how large you are. Whales might eat tons of krill per mouthful, but I'm pretty certain krill have a superior amount of biomass compared to whales. Same with ants: humans might have superior intelligence and enormous control over the environment, but, we have essentially equal biomass compared to ants. So, all in all, both r-species and k-species are about equal, if I'm not mistaken. K-species might be larger, but they are far less numerous; r-species are small, but far more numerous.

[Admiral Valdemar]

That leaves and interesting question of how much, in terms of biomass, mammals have over, say, insects. I'm actually thinking bacteria and other prokaryotes would be good contenders too. The local sewage processing plant has anaerobic cylinders for filtering waste and breaking it down that have 80 tons of bacteria each.

[Plekhanov]

Darwinism says there is always a way for the organism to go from A to B to C to D to E etc. without a point where no progress can be made. Why would it a land animal evolve into a whale when there are so many fish that were so better adapted to the water environment? Darwinism never predicts that something could NOT happen. Anything can evolve into anything else at any speed at any time. It does not FORBID anything?

Look around the world there are many aquatic and semi aquatic mammals, some like otters and hippos seem at home on land or in water, others like the duck billed platypus & sealion are fairly competent on land but are really built for the water then you have seals which are extremely clumsy on the land but still need to leave the water on occasion even if it’s for little other than to give birth and then at the other extreme cetaceans that spend their entire lives in the water.So you can actually still sea around us some of the intermediary stages that whatever it was that evolved into whales might well have gone through.

I suppose this begs the question though of why fish are so slow to fill these niches that reptiles and mammals beat them to it...

Maybe intelligence has something to do with it, cetaceans exhibit extremely complex hunting behaviours, such as bubble netting and other advanced co-operative tactics which as far as I’m aware are beyond fish. Perhaps mammalian intelligence gives them an edge over fish by allowing them to quickly change their behaviours to exploit new food sources and so forth.

[Akhlut]

That leaves and interesting question of how much, in terms of biomass, mammals have over, say, insects. I'm actually thinking bacteria and other prokaryotes would be good contenders too. The local sewage processing plant has anaerobic cylinders for filtering waste and breaking it down that have 80 tons of bacteria each.

That's a very difficult question to answer, especially with things that are difficult to classify as r-species or k-species. A grasshopper is certainly an r-species and a tortoise is certainly a k-species, but what about a rabbit?

And various unicellular organisms almost certainly outweigh everything else. A single drop of water from any non-treated source is literally swimming with little critters.

Plus, something I just considered: what about parasites? They outnumber free-living organisms by some absurd ratio (4:1, if I'm not mistaken). How would we accurately measure their biomass, especially in relation that we'd often include their biomass with the biomass of other creatures. And are they r-species or k-species? They often tend to be long-lived, but they're small and produce huge numbers of offspring and are controlled mainly by density independent factors (their hosts).

[Omega18]

Something that might be useful information wise is the following article talking about a transitional species between land animals and the whales of today. Check out the following article about an alligator like animal that was a mamalian ancestor to whales.

Gingerich said the legs and feet of the primitive whales were not designed for walking long distances.

"It's clear that these animals could hitch their way out of water and back in, like sea lions do today, but they were more aquatic than I realized," Gingerich said. The size and shape of their bones suggest that they had webbed hands and feet and probably also used their tails to propel themselves through the water.

http://news.nationalgeographic.com/news ... whale.html

Once later species headed out to sea over time they had a couple of advantages over fish. First of all, their ancestors had started with decent sized brains giving them a fair amount of intelligence, and this gave them a huge advantage over fish in the ocean. Secondly, taking in an oxygen supply in the air allows them to burn the oxygen aquired in this way much more rapidly, giving aquatic mammals much more speed than fish that need to take in their oxygen just through the water at a much slower rate. Extra speed is often a vital atribute in the water that gives many aquatic mammal species enough of an advantage to outweight needing to come up for air.[/quote]

[wolveraptor]

Whales also evolved in more sheltered inland lakes and rivers, only later moving out to the ocean. River-dwelling fish are no composition for even a semi-competent amphibious mammal. It was when they adapted wholely for the water that they began moving out into the big-league ocean.