Loren I. Petrich Sep2993 10:14AM Puzzler for Creationists: Dolphins and Whales All you net

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Loren I. Petrich Sep-29-93 10:14AM Puzzler for Creationists: Dolphins and Whales Organization: Lawrence Livermore National Labs, Livermore CA From: lip@s1.gov (Loren I. Petrich) Message-ID: <28cj9b$p08@s1.gov> Newsgroups: talk.origins All you net.creationists out there, how do you explain the fact that cetaceans (dolphins and whales) need to come up to the surface to breathe. These animals are fish-shaped and are excellent swimmers, yet they have this one serious deficiency. Why did this supposedly perfect creator create them that way??? And if that tickles your fancy, here is a rather short list of similar features, which are only the more apparent such features I have in a rather long list of such features. Aquatic-tetrapod air breathing and breeding on land ("tetrapod" includes all the land vertebrates). Aquatic animals like sea turtles, Galapagos iguanas, sea snakes, crocodilians, water birds (penguins, for example), pinnipeds (seals, sea lions, and walruses), sirenians (manatees and dugongs), and cetaceans (dolphins and whales) all have to come up to the surface to breathe, which is a serious limitation for an aquatic animal. And of these, only the sea snakes, sirenians, and cetaceans are completely aquatic, giving birth in the water; the rest either lay eggs or give birth on land. Needing to breathe air is perhaps most striking for cetaceans, which are otherwise very well-adapted for life in water, with their being fish-shaped and excellent swimmers. Stumpy tails and other such features of some domestic animals bred to have none. Snakes with vestigial limbs. Boa constrictors have small vestigial hind legs; these may aid in copulating. However, most other species of snakes lack this feature, and seem to do fine without them. Tadpoles. Immature frogs go through this phase, in which they look and act much like fish. Tails of human embryos. Though tails are a nearly universal vertebrate feature, and are present in all the embryos, they are lost in later growth in our species and the most closely related ones (the apes), leaving only a tiny bone on the pelvis, the coccyx. Jaw origins from gill bars. In jawed-vertebrate embryos, the jaws are formed from the gill bars closest to the mouth. In jawless fish (lampreys and hagfish), these gill bars stay gill bars. This circumstance indicates an origin of jaws from gill bars. Gill bars of tetrapod (land-vertebrate and descendant) embryos. The cartilage gill bars appear, only to disappear or be reworked with later growth. Of these animals, only amphibians have gills, and that only in the larval (tadpole) stage. Most adult amphibians and all the rest are air breathers; even the aquatic ones do not grow gills to use underwater. The mammalian amniotic sac. This is a vestigial eggshell that surrounds the fetus. Live birth evolved out of retaining an egg inside. Fused bones. These are bones that start out separate and become knitted together for added strength. Human examples are the skull and the pelvis (the latter fusion seems to be widespread in land vertebrates); birds have several bones in their front limbs (wings) fused. Some dinosaurs apparently had fused lower vertebrae, complete with tendons turned to bone, for supporting their tails. Fused teeth are sometimes in evidence; in our species (and probably most other mammal ones), the back teeth look something like two front teeth with their crowns fused. This is apparent from their greater size and their double roots. Bird alula or "bastard wing". A much-reduced digit on the front limb. The two others are retained, though they are fused into one piece. The wings of flightless birds. For most flightless birds, the wings are non-functional, aside from possible display functions. The only major exceptions are diving birds, like penguins, whose "wings" serve as control surfaces. In some cases, the wings are _very_ small, as for kiwis. The effect is to reduce the number of usable limbs from 4 to 2, which can hardly be called an improvement. Flounder eyes. On sea floors, there live these fish that lie on their sides. They have two eyes -- on one side of their heads. But they start off life with eyes on both sides of their heads, and one eye moves to the other side. Why two eyes instead of one? And why originally on both sides of the head? Original embryonic eye positions. In human and dog embryos, as in most other vertebrate embryos, the eyes are originally on the sides of the head. However, the eyes move forward as human and dog embryos grow, to make possible binocular vision. One human birth defect is for this process to be incomplete, making the eyes too far apart. Among the vast majority of the animals with backbones, the eyes are at the sides of the head; the main exceptions I know of are the bats, the primates, the carnivores, the owls, and possibly some of the more cerebrally endowed small carnivorous dinosaurs. In their family trees, they are surrounded with eyes-on-the-side animals, suggesting that binocular vision evolved several times. Giraffe neck lengths. Baby giraffes start out with necks whose relative length is similar to those of other ungulates; it is as they grow that they acquire the relatively long necks that the species is noted for. Human toes. Our feet have toes, one of which is big and slightly separated from the others. For walking, there is no special need of having a split front end of the foot; it should not be surprising that the toes are small. But they are there, and in most primate species they are much more prominent. In some species at least, the big toe points outward, just like a thumb. Interestingly, in some early hominid species, the toe bones were relatively longer than in our species. Wisdom teeth. Our jaws are a bit small for these late-erupting teeth; some people have them, while others do not. And some people, like myself have two upper wisdom teeth but no lower wisdom teeth. Solid-color equids having genes for making stripes. The living equids are the domestic horse, its wild progenitors, the donkeys, and the zebras and quaggas. Matings of different breeds of solid-color equids (horses and donkeys) sometimes produce offspring with zebra-like stripes. It is as if the genes for making stripes, which are expressed in zebras, are switched off in the solid-color equids, only to re-emerge in certain circumstances. Outsized hind legs of some four-legged dinosaurs. _Stegosaurus_, especially, had hind legs much bigger than its front legs. This is probably a byproduct of being descended from a two-legged ancestor that went back to walking on all fours. Many of the dinosaurs walked on their hind limbs only, with the front limbs remining at various levels of development. In _Tyrannosaurus_, they are _very_ small, though still there, which has led to the suggestion that they are vestigial. The earliest dinosaurs known, like _Herrerasaurus_, were like this. Transitional cases? Possibly! _Iguanodon_ or some other such dinosaur apparently walked on two legs when juvenile, and on all fours when adult (and a lot heavier). Flowers of self-pollinators. Some flowering plants, like dandelions, are self-pollinating, and thus have no need of flowers to attract pollen carriers. -- /Loren Petrich, the Master Blaster /lip@s1.gov


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