Weird animal forms (Introduction)

by dhw, Wednesday, May 18, 2016, 12:06 (2892 days ago) @ David Turell

DAVID: Since we are discussing how evolution develops lifestyles and oddball results of innovation I've brought up the 8-9 steps to whales, which makes no sense as evolutionary improvements, since in my view all it does is create complexities of how to solve the problems of mammals in water.-As always we can only speculate, but if there is a problem which needs to be solved, the solution is an improvement! Whales started as land mammals, so maybe where their ancestors lived, food was more abundant in the water. Every subsequent stage in their evolution may have resulted from different adjustments to aquatic conditions. Each change would have taken place in existing specimens, and if the changes were useful/advantageous under the conditions that existed at the time, they would have survived, and the earlier form would presumably have died out. Isn't all that a reasonable hypothesis? Problem-solving, useful, advantageous - don't these all suggest improvement? I really can't believe that organisms would decide to become more complex just for the sake of complexity. -DAVID: This article, while looking at the genetics that might have created them, also discusses the many physical adaptations that come with the giraffe:-http://phys.org/news/2016-05-giraffe-neck-clues-revealed-genome.html-QUOTE: Most people assume that giraffes' long necks evolved to help them feed. If you have a long neck, runs the argument, you can eat leaves on tall trees that your rivals can't reach. But there is another possibility. The prodigious necks may have little to do with food, and everything to do with sex.
"The evidence supporting the high-feeding theory is surprisingly weak. Giraffes in South Africa do spend a lot of time browsing for food high up in trees, but elsewhere in Africa they don't seem to bother, even when food is scarce.-Again we can only speculate, but does anyone know precisely what the conditions were when the giraffe first evolved its long neck? Is it not possible that in a particular region at a particular time, food became scarce and it was advantageous to reach higher? Once a structural change has taken place, there is no reason for it to die out unless it proves disadvantageous. There is certainly no point in using current conditions as a yardstick. Organisms will take whatever food is available at the time, high or low. -QUOTE: "Male giraffes fight for females by “necking”. They stand side by side and swing the backs of their heads into each others' ribs and legs. To help with this, their skulls are unusually thick and they have horn-like growths called ossicones on the tops of their heads. Their heads, in short, are battering rams, and are quite capable of breaking their opponents' bones."-I'm afraid I can't take this seriously as a motive for innovation. Their ancestors managed to mate without long necks, and there is no reason to assume the males didn't fight. So why on earth would the males evolve long necks just in order to fight one another? -David's comment: Tell me this developed as a drive for improvement. Rubbish. The physiology of mammals shows us that high blood pressure causes hardening of arteries, damages kidneys, results in stokes, in heart failure, etc. The giraffe has modifications so none of this happens. Also other modifications protect it from poisonous acacia leaves. Its tongue is thicker than shoe leather to protect it from acacia thorns. (I've actually felt a tongue while feeding one in Kenya). There is lots of nutritious vegetation in Africa. Why all this bother. And their thick skulls batter other males, I'm sure without concussions. Not all evolution is obvious improvement, but instead a built in structural inventiveness, which doesn't seem to account for the physical complications as deterrents.-If it's that disadvantageous and dangerous, why do you think the phenotype complexification mechanism bothered to invent it in the first place? As above, does it really make sense that organisms should invent new complexities, or your God should dabble, just for the sake of complexity? Even with your anthropocentric interpretation of evolution, what possible advantage can it be to humans to have pre-giraffes reorganizing themselves so they can have long necks? Doesn't the conventional view make more sense: that at some time in some place conditions were such that a longer neck made it easier for the pre-giraffe to get food (THAT would be the improvement), and the cell communities cooperated under the instructions of the phenotype complexification mechanism aka autonomous inventive mechanism aka intelligence to make all the other adjustments necessary?