324 I The Process of Evolution 



Heritability the genetic variance divided by the phenotypic variance; 

 an estimator of the degree of resemblance between offspring and parent. 



Hermaphroditic possessing the phenotype of both sexes in organisms 

 with male-female sex differentiation. 



Meter ochromatic describing entire chromosomes or portions of the chro- 

 mosomes that do not manifest the usual prophase-telophase transforma- 

 tions and appear to lack genes with major phenotypic effect. 



Heterogametic producing gametes with differing chromosome com- 

 plements. 



Heterokaryotic containing within one cell or coenocyte nuclei of dif- 

 ferent genotype. 



Heterotrophic requiring organic carbon for nutrition. 



Higher categories taxonomic categories above the level of genus in the 

 established hierarchy. 



Holometabolous having a pattern of development that includes distinctly 

 different egg, larval, pupal, and adult stages. 



Homologue one of the set of two or more chromosomes which are identi- 

 cal with respect to their constituent loci. 



Horotelic evolution rates of evolution falling within the distribution 

 (asymmetrical with a mode nearer the upper than the lower end) most 

 commonly found when evolutionary rates are plotted in a frequency 

 distribution. 



Hybridization gene flow between populations; usually restricted to popu- 

 lations recognized as distinct by taxonomists. 



Hydrated protein a protein molecule about which water molecules are 

 held. 



Imprinting the imposition of a stable behavior pattern by exposure, dur- 

 ing a particular period in development, to one of a restricted set of 

 stimuli. 



Induction determination of the developmental fate of one cell mass by 

 another. 



Interstitial segment that portion of a chromosome between a trans- 

 located segment and the centromere. 



Introgression incorporation of genetic material from one population into 

 that of another by repeated backcrossings; usually restricted to popu- 

 lations regarded as distinct by taxonomists. 



Inversion reversal of the sequence of a portion of a chromosome. 



Kappa particles particles of DNA within the cytoplasm of certain indi- 

 viduals of some species of Paramecium that result in the death of other 

 individuals with certain genotypes. 



Karyotype the characteristic phenotype of the chromosomes of an or- 

 ganism; usually used with respect to the chromosomes at mitotic meta- 

 phase. 



L chromosomes see limited chromosomes. 



Limited chromosomes heterochromatic chromosomes restricted to the 

 germ line in some species of the fungus gnat Sciura. 



