Moritz9Notes - Biology 1BEvolution Lecture 9 (March 15,...

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Moritz Lecture 9 Notes - 1 Biology 1B—Evolution Lecture 9 (March 15, 2010), Speciation Processes Ensatina eschscholtzii Salamanders mimic newts with yellow stripes over their eyes (in the Bay Area) Their geographic range covers much of California, excluding the Central Valley: The ancestral range was in the redwood forests of the north, but they have migrated independently along the west coast and the Sierra Nevadas There are gradual transitions along the coasts: on the west, the salamanders are plain and cryptic; on the east, they are disrupted (disruptive against leaf litter background), blotched, and highly colored In the foothills of the Sierra Nevada, there is a hybrid zone where the coastal form and Sierra form have come back together In some mountains behind San Diego, the plain and blotched overlap. Yet, just to the north at Palomar, they overlap and form hybrids. Could be considered a “ring species” because they make a loop of gradual transitions with RI at the terminus Current taxonomy is that there is one species with 7 sub-species, but they could
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This note was uploaded on 07/31/2010 for the course BIO 1B taught by Professor Carlson,mischel,power during the Spring '07 term at University of California, Berkeley.

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Moritz9Notes - Biology 1BEvolution Lecture 9 (March 15,...

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