Morphogenesis in Protozoa

Abstract

Since not all Protozoa possess kinetosomes it may be wondered whether or not analyses for ciliates has general applicability to Protozoa as a whole. Prob ably yes, for, while many are not equipped with ectoplasmic cortex, and since it is the cortex that differentiates Protozoa, each cortical locus probably possesses specific diagnostic elements on the molecular level. The cortical mechanisms specif ically were among the earliest systems of morphogenesis to evolve. Kinetosomes may be traced back as far as the first protistan unicells which developed flagellary locomotion. From these organisms the infraciliary apparatus presumably passed into the plant kingdom by way of other algae and into the animal kingdom via other Protozoa. Kinetosomes are still present in most algal classes where they are of vital importance in spore dispersal and gamete locomotion, and in all protocoan classes where they reach their fullest development in the ciliates.