Dorsal Quotes

Arthropods and vertebrates share some broad features of general organization - elongated, bilaterally symmetrical bodies, with sensory organs up front, excretory structures in the back, and some form of segmentation along the major axis. But the geometry of major internal organs could hardly be more different... Arthropods concentrate their nervous system on their ventral (belly) side as two major cords running along the bottom surface of the animal. The mouth also opens on the ventral side, with the esophagus passing between the two nerve cords, and the stomach and remainder of the digestive tube running along the body above the nerve cords. In vertebrates, and with maximal contrast, the central nervous system runs along the dorsal (top) surface as a single tube culminating in a bulbous brain at the front end. The entire digestive system then runs along the body axis below the nerve cord. (Stephen Jay Gould)
Nereus spun and expanded, turning into a killer whale, but I grabbed his dorsal fin as he burst out of the water. A whole bunch of tourists went, "Whoa!" I managed to wave at the crowd. View quote
Rick Riordan
These arguments led Darwin to his denial of progress as a consequence of the "bare bones mechanics” of natural selection-for this process yields only local adaptation, often exquisite to be sure, but not universally advancing. The mammoth is every bit as good as an elephant-and vice versa. Do you prefer a marlin for its excellent spike; a flounder for its superb camouflage; an anglerfish for its peculiar "lure” evolved at the end of its own dorsal fin ray; a seahorse for its wondrous shape, so well adapted for bobbing around its habitat? Could any of these fishes be judged "better” or "more progressive” than any other? The question makes no sense. Natural selection can forge only local adaptation-wondrously intricate in some cases, but always local and not a step in a series of general progress or complexification. View quote
Stephen Jay Gould