GLOSSARY 



Abdomen. The pHDsterior portion of the main part of the animal body. 



Acid. A chemical compound which contains one or more hydrogen ions 

 that ionize in solution. 



AcdxoMATE. The accElomate animals are those which have no coelom; 

 for example, the Coelenterata. 



Acquired characters. Non-inheritable variations caused by the contact 

 of the organism with its environment. 



Acquired immunity. Immunity to disease, the result of having had the 

 disease. 



Adaptation. The characteristics of the organism which tend to fit it for 

 the environment. 



Adrenalin. The hormone produced by the medullary portion of the 

 adrenal glands. It afFects blood pressure, output of muscle sugar, 

 plain muscle of the reproductive system, and has still other actions. 



Agametic reproduction. The reproductive process that involves a bud, 

 a fragment, or a spore. 



Allelomorphic genes. Genes that are located in different chromosomes 

 but influence the same inheritable character. Thus, the gene for blue 

 eye color and the gene for brown eye color are allelomorphic genes. 



Alternative characters. Differences in the same feature within the 

 species. For example, blue and brown are alternative eye color char- 

 acters in human inheritance. 



Amino-acid. An organic compound containing COOH and NHo; es- 

 sential components of protein. 



Amitosis. Direct cell division involving an unequal distribution of 

 chromatin to the daughter cells. 



Amnion. A membranous sac filled with amnionic fluid which surrounds 

 the developing embryos of birds and marmnals. 



Amphimixis. As employed here the word refers to the fundamentally 

 sexual process among Protozoa whereby two individuals interchange 

 micronuclear materials. 



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