Search results for "Selective advantage"
showing 4 items of 4 documents
Conditions for the spread of conspicuous warning signals: A numerical model with novel insights
2007
The initial evolution of conspicuous warning signals presents an evolutionary problem because selection against rare conspicuous signals is presumed to be strong, and new signals are rare when they first arise. Several possible solutions have been offered to solve this apparent evolutionary paradox, but disagreement persists over the plausibility of some of the proposed mechanisms. In this paper, we construct a deterministic numerical simulation model that allows us to derive the strength of selection on novel warning signals in a wide range of biologically relevant situations. We study the effects of predator psychology (learning, rate of mistaken attacks, and neophobia) on selection. We a…
The selective advantage of cystic fibrosis heterozygotes tested by aDNA analysis: A preliminary investigation
2000
Recently a heterozygote advantage was suggested to explain the high incidence (1:25 carrier individuals in Europeans) of the cystic fibrosis gene. This selective advantage was speculated to be due to a high resistance to chloride-secreting diarrhea, including cholera. Up to now the major efforts to test directly this hypothesis have been limited to animal models.
Why are wasps so intimidating: field experiments on hunting dragonflies (Odonata: Aeshna grandis)
2003
Abstract The mechanisms of aposematism (unprofitability of prey combined with a conspicuous signal) have mainly been studied with reference to vertebrate predators, especially birds. We investigated whether dragonflies, Aeshna grandis, avoid attacking wasps, Vespula norwegica, which are an unprofitable group of prey for most predators. As a control we used flies that were painted either black or with yellow and black stripes. The dragonflies showed greater aversion to wasps than to flies. Black-and-yellow-striped flies were avoided more than black ones, suggesting that aposematic coloration on a harmless fly provides a selective advantage against invertebrate predators. There was no signifi…
Selektionstheorie und Rassenbildung beim Menschen
1952
So far, the applications of the theory of selection to human race formation have primarily considered the selective quality of individual race characters which are preferred by classification. However only few physiologically important race characters have been found to have an evident selective advantage. It is the climate laws, however, that prompt the assumption that selection will take place according to differences of vitality and fertility under certain climatic conditions and that the visible race characters are but incidental effects of pleiotropic gene. It also appears that, in contrast to selection, mutability must be given more consideration to-day than before. For instance the e…