The Evolution of Evolution 119If you had any doubts that you once had ancestors with fish-like gills and a tail,
figure 4.11 shows what you looked like 5 weeks after fertilization. Why did you have
pharyngeal pouches (predecessors of gills) and a tail if you had not descended from
ancestors with those features?
Biogeography
As was pointed out in chapter 3, the great expeditions of discovery in the 1700s and 1800s
soon produced a huge diversity of animals and plants that were unfamiliar to Europeans
and not anticipated by the authors of either the Noah’s ark story or Linnaeus in 1758. Not
only do these animals and plants render any version of the Noah’s ark story impossible, but
they created another problem as well. They are not distributed around the earth in pattern
from Mount Ararat in Turkey (the supposed landing site of the ark) but instead have their
own unique distribution patterns that only make sense in light of evolution.
Darwin got a hint of this on the Galapagos Islands, where each island had a slightly dif-
ferent species of giant tortoise or finch. Instead of populating the islands with the same spe-
cies as occurred on the mainland, apparently God had seen fit to put new, unique species on
each island (and this phenomenon is true of islands in general). Later studies of the unusual
animals of exotic places further confirmed the fact that these far-flung locations were largely
populated with unique animals found nowhere else, and their distribution patterns made
no sense in the context of migration from the ark. For example, Australia is home to its
own unique fauna of native pouched mammals, or marsupials (fig. 4.12). These include not
only the familiar kangaroo and koala, but many other creatures that evolved to fill the same
ecological niches that placental mammals occupy on other continents. There are marsupial
equivalents of placental wolves, cats, flying squirrels, groundhogs, anteaters, moles, and
mice. If the animals had all migrated away from the ark, why had nothing but marsupials
arrived in Australia and then apparently evolved to fill the niches left vacant by the lack of
placentals?
Other patterns are equally persuasive. For example, many of the southern continents
have at least one flightless bird species, all members of the primitive group known as ratites.
FIGURE 4.11. This is what you looked like 5 weeks af-
ter conception. You still had many fishlike features,
such as a well-developed tail and the embryological
precursors of gill slits, both of which are lost in most
human embryos as they develop. (From IMSI Photo
Images, Inc.)