- The ratites are a very old clade of flightless birds
that include the ostriches in Africa, rheas in South
America, emu and cassowaries in Australia, and
kiwis and recently extinguished moas in new
Zealand. South American tinamous, which are
capable of flight, are closely related to the rat-
ites. The “Gondwanan distribution” of these
birds has often been attributed to vicariance, but
some researchers have questioned this phylog-
eny and distributional history. Read several phy-
logenetic studies of the ratites and discuss how
best to explain their distribution: A. Cooper et
al., 2001, Nature 409: 704–707; o. Haddrath and
A. J. Baker, 2001, Proc. Royal Soc. Lond. B 268:
939–945; S. J. Hackett et al., 2008, Science 320:
1763–1768; and A. J. Baker et al., 2014, Mol. Biol.
Evol 31: 1686–1696. - in Chapters 4 and 6 you saw that many charac-
teristics of most species have the genetic varia-
tion that is required for those characteristics
to evolve, and that many examples of rapid
adaptation to human-altered environments
have been documented. Discuss whether or
not this observation is inconsistent with the fact
that many organisms display phylogenetic niche
conservatism. - in some cases, it can be shown that species are
physiologically incapable of surviving tempera-
tures that prevail beyond the borders of their
range. Do such observations prove that cold
regions have low species diversity because of
their harsh physical conditions?- By far the most effective way of saving endan-
gered species is to preserve large areas that
include their habitat. for social, political, and
economic reasons, the number and distribution
of areas that can be allocated as preserves are
highly limited. it might be easier to save more
species if areas of endemism were correlated
among different taxa, such as plants, birds, and
mammals. Are they correlated? (See, for exam-
ple, n. Myers et al., 2000, Nature 403: 853–858;
J. R. Prendergast et al., 1993, Nature 365: 335–
337; and A. P. Dobson et al., 1993, Science 275:
550–553.) - Would you expect large numbers of species
in a region to have had similar histories of geo-
graphic distribution? Why or why not? How
could you use phylogeographic analyses, such
as illustrated in figure 18.14, to address this
question? - in what ways have human activities influenced
the biogeographic distribution of animals? How
have humans caused animal ranges to expand or
contract?
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