The Discovery of Evolution 31© Dana WalrathAn example of analogy: The wings of birds and butterflies are both used for flight and share similar
appearance due to their common function. However, the course of their development and their
structure differ.Visual Counterpoint© Fritz Polking/Peter Arnold, Inc.
developmental sequence. Only homologies are relevant
for constructing evolutionary relationships.
Through careful comparison and analysis of organ-
isms, Linnaeus and his successors have grouped species
into genera and into even larger groups such as families,
orders, classes, phyla, and kingdoms. Each taxonomic
level is distinguished by characteristics shared by all the
organisms in the group.The Discovery of Evolution
Just as European seafaring and exploration brought about
an awareness of the diversity of life across the earth, con-
struction and mining, which came with the onset of in-
dustrialization in Europe, led to an awareness of change
in life forms through time. As work like cutting railway
lines or quarrying limestone became commonplace, fos-
sils, or preserved remains, of past life forms were brought
into the light.
At first, the fossilized remains of elephants and giant
saber-toothed tigers in Europe were interpreted accord-
ing to religious doctrine. For example, the early 19th-
century theory of catastrophism, championed by French
paleontologist and anatomist Georges Cuvier, invoked
natural events like the supposed Great Flood chronicled
in Genesis to account for the disappearance of these
species in European lands. Another French scientist,
Jean-Baptiste Lamarck, was among the first to suggest a
mechanism to account for diversity among living crea-
tures that did not rely upon scriptures. His theory of the“inheritance of acquired characteristics” proposed that
behavior brought about changes in organisms’ forms.
The famed example was that the first giraffe gained its
long neck by stretching to reach the leaves on the high-
est treetop branches and in turn passed this acquired
long neck onto its offspring. While Lamarck’s theory has
long since been disproved as a mechanism to account for
biological change, his proposal seems likely as a change
mechanism for cultural inheritance, and he is credited
with making the connection between organisms and the
environments they inhabit.
During this same time, British geologist Sir Charles
Lyell championed uniformitarianism—a theory that
accounts for variation in the earth’s surface. According
to Lyell, these variations are the result of gradual changes
over extremely long periods of time; although the changes
are not obvious at the moment, they are caused by the
same natural processes, such as erosion, that are immedi-
ately observable. Because the time span required for uni-
formitarianism is so long, this theory was incompatible
with literal interpretations of the Bible, in which the earth
is believed to be only about 6,000 years old.
With industrialization, however, Europeans became
generally more comfortable with the ideas of change and
progress. In hindsight, it seems inevitable that someone
would hit upon the scientific concept of evolution. So it
was that, by the start of the 19th century, many naturalistsnotochord A rodlike structure of cartilage that, in vertebrates,
is replaced by the vertebral column.