Evolution__3rd_Edition

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Summary
1 A number of lines of evidence suggest that species
have evolved from a common ancestor, rather than
being fixed in form and created separately.
2 On a small scale, evolution can be seen taking place
in nature, such as in the color patterns of moths, and in
artificial selection experiments, such as those used in
breeding agricultural varieties.
3 Natural variation can cross the species border, for
example in the ring species of salamanders, and new
species can be made artificially, as in the process of
hybridization and polyploidy by which many agricultural
and horticultural varieties have been created.
4 Observation of evolution on the small scale, combined
with the extrapolative principle of uniformitarianism,
suggests that all life could could have evolved
from a single common ancestor.
Further reading
CHAPTER 3 / The Evidence for Evolution 69
5 Homologous similarities between species (understood
as similarities that do not have to exist for any
pressing functional reason), suggest that species
descended from a common ancestor. Universal
homologies a such as the genetic code a found in all
living things suggest that all species are descended
from a single common ancestor.
6 The fossil record provides some direct evidence of
the origin of new species.
7 The order of succession of major groups in the fossil
record is predicted by evolution, and contradicts the
separate origin of the groups.
8 The independent creation of species does not
explain adaptation; evolution, by the theory of natural
selection, offers a valid explanation.
Eldredge (2000), Futuyma (1997), and Moore (2002) have written books about creationism
and the case for evolution. The latest version of creationism is “intellgent
design” creationism, which does not challenge evolution in the sense of this chapter: on
it see Chapter 10 in this book, and Pennock (2000, 2001). Chapters 10–14 of On the
Origin of Species (Darwin 1859) are the classic account of the evidence for evolution.
Jones (1999) remakes Darwin’s case, using modern examples, including drug resistance
in HIV.
Palumbi (2001a, 2001b) describes many examples of evolution in response to environmental
changes that humans have caused, including HIV evolution; he also does
some interesting sums on the economic cost of that evolution. Reznick et al. (1997)
describe another good example of evolution in action: changes to the life histories of
guppies in Trinidad. See Ford (1975), Endler (1986), and the references in Hendry &
Kinnison (1999) for further examples. Huey et al. (2000) discuss another example of
rapid evolution of a cline within a species, like the house sparrow example in the text
but with the addition that the newly formed cline in North America parallels one in
Europe.
Irwin et al. (2001b) review ring species, including the Californian salamander. On
polyploidy in plants, see the references in Chapter 14. On the genetic code, see Osawa
(1995). Zimmer (1998) describes fossil whales and tetrapods. Ahlberg (2001) includes