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