Biology Reference
In-Depth Information
1300
2
2
1040
2
2
780
2
2
2
520
2
2
2
260
2
2
2
2
2
2
2
2
2
0
2
2
0
7
14
21
GENERATION
Fig. 8.1
Population growth over 21 generations (including the founding generation = generation
0) given the initial trial input conditions described in the text (the basic input fi le output = points
marked “2”). Basically, the species is an annual and the population is initiated with 20 founders
in two lines starting at the lower left corner of the preserve. After 20 bouts of reproduction,
the number of individuals approaches 1300. Each data point here, and in following graphs on
edge effects, represents the mean of 30 runs. The symbol “2” is used here to indicate output
values for this particular trial, which was one of several conducted simultaneously.
0,0
-a,-a
-b,-b
Fig. 8.2
Investigating population genetics edge effects with NEWGARDEN. In the initial
basic input trial, 20 founders in two rows are placed at the lower left (starting at 0,0) of a
virtual “preserve” of grid points, indicated here by the upper right square. In this initial trial,
NEWGARDEN generates statistics for a population that develops within this preserve over
several generations. In a subsequent series of trials, everything is held constant, except that the
border incrementally recedes from the stationary two lines of founders (the lower left corner of
the preserve being designated -a, -a in one trial, -b,-b in another trial, and so on). By comparing
population statistics across these trials, we can examine the intensity of genetic diversity
retention edge effects, if any. For a species with a given set of life history characteristics, the
shortest border-distance-from-founders at which no edge effects are fi rst detectable compared
to an extremely large preserve where founders are placed at a great distance from any border
would indicate the minimum distance from a border at which founders could be introduced
to avoid population genetics edge effects, under the given conditions.
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