摘要:

The meaning of the terms atomism, epigenesis, preformation and pre‐existence is clarified by a historical analysis. Today, two alternative models of organismic change are opposed to each other. Atomism views the organism as being composed of traits or atoms: it implies the possibility of gradualistic change and a nominalistic species concept, while an increase in complexity is identified as an addition of new parts. Epigenesis, in contrast, implies the possibility of saltational change and an essentialistic species concept, while an increase in complexity is considered to result from an enhanced compartmentalization and differentiation of the originally homogeneous primordium. Schwabe&Warr's (1984) ‘genetic potential hypothesis’ qualifies as pre‐existence at the genotypi

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01762.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A study of the population genetics of the estuarine bivalve Geukensia demissa (Dillwyn) in southern California marshes revealed significant spatial and temporal variation in leucine aminopeptidase‐1 (LAP‐1) gene frequencies which were correlated with environmental salinity. S California populations also generally show a deficit of heterozygotes at the LAP‐1 locus with the degree of this deficit also correlated with environmental salinity. The results of this study are similar to previous studies onMytilus edulisLinné where it has been proposed that antagonistic directional selection in low vs. high salinity environments acts to maintain the LAP‐1 polymorphism. However, a general similarity between the genetic patterns for LAP‐1 and other loci inG. demissain S California makes a strict selectionist interpretation difficult. A similar study of G. demissa in San Francisco Bay failed to detect heterogeneity in allele frequencies or significant heterozygote deficits over gradients in environmenta

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01763.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Carotenoid concentration in model swallowtail butterflies is exceptionally high; it is suggested that they may exert a photo‐protective function in species storing nitrophenanthrenes. Carotenoid concentration in the viceroy is also high. Again, it is suggested that this represents a protective mechanism for Lepidoptera feeding onSalixwhich contains salicin. Such a mechanism would not be required by the monarch storing cardenolide

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01764.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

TheAdh‐1polymorphism ofDrosophila buzzatiiwas studied in terms of the effects of the larval substrate (laboratory food andOpuntia strictatissue inoculated with live yeast species) on larval survival, development time and subsequent adult size, using the three commonAdh‐1genotypes. Studies with laboratory food yielded mixed results, but in general theAdh‐1b/Adh‐1bgenotype was superior toAdh‐1c/Adh‐1cwith the heterozygote intermediate. Studies with the natural substrate (Opuntia stricta tissue) using mono‐ and bicultures of four associated yeast species also showed that theAdh‐1b/Adh‐1bgenotype develops faster and survives better thanAdh‐1c/Adh‐1c.There were no genotype‐by‐yeast interactions which might explain the maintenance of the polymorphism. Drosophila buzzatii larvae develop faster and attain larger adult sizes when raised on bicultures of yeasts as compared with the c

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01765.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The phylogenetically and morphologically diverse patterns ofCharaxescan be reduced to a simple set of pattern elements which can be homologized throughout the genus. At least five types of correspondence (homologies) exist among pattern elements: those between (1) species, (2) forewing and hindwing, (3) dorsal and ventral wing surface, (4) serial wing‐cells, and (5) individual pattern elements within a single wing‐cell. Differences inCharaxescolour patterns result from the distortion, elaboration, enlargement, reduction or loss of individual pattern elements. Further variation is often the result of dislocation of pattern elements from their serial homologues in neighbouring wing‐cells, and fusion of individual pattern elements to create larger areas of colour. The type of analysis presented in this paper should be broadly applicable within the Lepidoptera and may prove useful in studying the systematics of colour patterns and the evolution of the developmental system that gives rise to

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1986.tb01766.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY