Biology Reference
In-Depth Information
FIGURE 10.5
Allometry of
lever arm lengths and shape.
(A)
Sciurus
jaw with selected
lever arm lengths shown as
dashed lines. 1: anterior molar
output arm; 2: anterior tempora-
lis input arm; 3: anterior deep
masseter input arm; 4: superfi-
cial masseter input arm. (B)
Scatter-plots of contrasts for the
four lever arms for 23 sciurine
species. (C) Deformed grid
showing shape change corre-
lated with size increase inferred
from contrasts (
Figure 10.4
).
produce evolutionary change. Numerous potential constraints on adaptive evolution have
been proposed, from the limited mechanical properties of materials used to build organ-
isms, to correlations of parts that are not congruent with the pattern of correlated changes
favored by selection (
Seilacher, 1979; Gould, 1984; Maynard Smith et al., 1985
). Such
