Biology Reference
In-Depth Information
1.
Alien Species and
Accelerated Evolution
“A growing appreciation that organic evolution, like mountain building, is an
ongoing rather than simply historical process has stimulated an infusion of
evolutionary thinking into mainstream ecology. Foremost among the factors
that have fostered this development are reports of remarkable adaptive evolu-
tion known to have taken place in recent decades. . . . ”
—C
ARROLL ET AL
. (2001)
Potato late blight (
Phytophthora infestans
) is a fungal disease of the Irish
potato (
Solanum tuberosum
) and its relatives. The potato itself was domes-
ticated in the Andean region of South America, whereas the blight fun-
gus is believed to be native to the TolucaValley of Mexico.The potato was
introduced to Europe in the 1500s, and became a major food plant in Ire-
land and many other countries. A strain of the blight fungus somehow
reached western Europe in the mid-1840s, where, coupled with weather
conditions favorable to its development, it decimated potato crops. In Ire-
land, the almost total loss of the potato crop led to famine, in which 1.5
million people died and many more were forced to emigrate. Closely
related strains of the fungus have since invaded all major potato-growing
areas of the world. In the twentieth century, these strains have been more
or less controlled by a combination of resistant potato varieties, fungicidal
treatments, and sanitation.
Prior to the 1980s, strains of the blight fungus affecting potato and
tomato (
Lycopersicon esculentum
) crops were of a single mating type, which
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