Homologous 



Refers to structures of organisms that possess the same 

 phylogenetic origin, e.g., wings of bats and forelimbs of 

 a rabbit. 



Homologous Chromosomes 



The two Chromosomes (q. v.) occurring in each pair in 

 Diploids, each derived from a separate parent. 



Homologue 



A pair of Homologous chromosomes, (q. v.). 



Homoplastic 



Refers to organisms which have organs resembling each 

 other because of the evolution along similar paths, but the 

 organs are not Homologous, e.g., Lagomorphs and Rodents. 



Homoteneity (Homotony) 



The Homogeneity (q. v.) of a Vegetation type in contrast 

 to that of a Stand. 



Homozygous 



Refers to an organism resulting from the fusion of 

 Gametes carrying the same genes, cf. Heterozygous. 



Hook Order 



A social order or rank in horned animals determined by 

 the aggressive use of horns. 



Hopkins Bioclimatic law 



See Bioclimatic law. 



Horizon (Soil) 



A layer of soil approximately parallel to the soil surface, 

 with distinct characteristics produced by soil-forming proc- 

 esses. See A horizon, B horizon, C horizon. 



Hormone 



A chemical substance produced in one part of an organ- 



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