Showing papers by "Jonathan B. Losos published in 1989"
TL;DR: Variation in leg length among Anolis might represent an evolutionary trade-off between maximizing sprint speed and maximizing stability on thin perches.
Abstract: We investigated the mechanistic basis for the observed correlation between leg length and perch size among West Indian Anolis lizards by testing the hypothesis that species use those perches upon which they can move most effectively. We used four Anolis species which differed in leg length and perch use in nature. We measured maximum sprint speed on rods of several sizes. Longer-legged species ran faster on thick rods. The speed of all species declined on thinner rods, but long-legged species were affected to a greater extent in that all species ran at approximately the same speed on the smallest rod. The short-legged A. valencienni experienced much less difficulty moving on thin rods than did the other species. Variation in leg length among Anolis might thus represent an evolutionary trade-off between maximizing sprint speed and maximizing stability on thin perches.
315 citations
TL;DR: The scant natural historical data available for this species suggests that lizards do not use their parachuting capability, and that dorsoventral flattening may have evolved for some other purpose, and Leiolepis might serve as a useful model in understanding the evolution of gliding lizards.
Abstract: Leiolepis belliani, a cursorial, beach-dwelling lizard, moves by running and jumping. The lizards' ability to flatten dorsoventrally, thereby increasing surface area and decreasing wing loading, may also confer parachuting ability. We measured locomotor performance of three ecologically relevant tasks: running, jumping and parachuting. In addition, we investigated whether, with the effect of size removed, locomotor performance capabilities are correlated, and whether they correlate with morphological features. Larger lizards fell and ran faster and jumped further. Lizards that were experimentally prevented from flattening fell faster than control lizards. When the effects of size were removed, limb length was uncorrelated with jumping and running performance; performance measures also were not correlated amongst themselves. The scant natural historical data available for this species suggests that lizards do not use their parachuting capability, and that dorsoventral flattening may have evolved for some other purpose. Leiolepis might serve as a useful model in understanding the evolution of gliding lizards (e.g. Draco).
50 citations
TL;DR: Simberloff and Boecklen (1981) constructed null models to test claims in the literature that species assemblages exhibited either unusual constancy or unusually large minimum ratios, and found that observed size-ratio distributions were indistinguishable from those generated by the null model.
Abstract: Hutchinson's (1959) \"Homage to Santa Rosalia or Why Are There so Many Kinds of Animals?\", coupled with MacArthur and Levins' (1967) theory oflimiting similarity, established the idea that competition prevents coexistence of species that are morphologically too similar (see also Carothers [1986]). Subsequently, numerous authors have reported either that the ratio of sizes of adjacent species in a size-ordered assemblage tends toward constancy or that all ratios exceed some minimum \"limiting similarity.\" Simberloff and Boecklen (1981) constructed null models to test 28 claims in the literature that species assemblages exhibited either unusual constancy or unusually large minimum ratios. In most cases, they found that observed size-ratio distributions were indistinguishable from those generated by the null model. Their paper has been widely cited in support of the position that little evidence exists for such \"Hutchinsonian ra-
21 citations