Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 20, 2025
The last of this long series of researches is that of Hamann , who investigates the similar structures which occur in the oral region of the Rhizostome jelly-fishes. While agreeing with Cienkowski as to the parasitic nature of the yellow cells of Radiolarians, he holds strongly that those of anemones and jelly-fishes are unicellular glands.
All living organisms consist, then simply of cells. Those consisting of but one cell are termed unicellular; those comprising more than one cell are called pluricellular. The unicellular organism is the unit of life on this earth. Yet tiny and ultimate as it is, every unicellular organism is possessed of an independent and "free living" existence.
In all animals and plants above the lowest the germ is a nucleated cell, using that term in its broadest sense; and the first step in the process of the evolution of the individual is the division of this cell into two or more portions. The process of division is repeated, until the organism, from being unicellular, becomes multicellular.
But in any case, as we contemplate the length of time during which such well marked diseases as diphtheria, leprosy, or the plague have been known, we must acknowledge that these unicellular forms seem to breed true during a most astonishingly long period. How can we deny that this "persistence" of these unicellular forms constitutes a very strong argument in favor of the "fixity" of these forms?
Multitudinous and varied as are the creatures which compose this immense organic world, they nevertheless exhibit a very remarkable uniformity of composition in their essential structure. Every living creature from a man to a mushroom, or even to the smallest animalcule or unicellular plant is always partly fluid, but never entirely so.
We must emphasize that these little animals correspond in all essential respects to the cells of our bodies; they are unicellular animals. And the cell once developed remains essentially the same structure, modified only in details, throughout higher animals. And these unicellular animals have the rudiments of all our functions.
At the commencement of it the oldest and simplest organisms were formed by spontaneous generation the Monera, with which the history of life on our planet opened. During this period the whole of the invertebrate ancestors of the human race were evolved from the unicellular organisms.
While by the second "the germ-cells are no longer looked upon as the product of the parent's body, at least as far as their essential part the specific germ-plasm is concerned; they are rather considered as something which is to be placed in contrast with the tout ensemble of the cells which make up the parent's body, and the germ-cells of succeeding generations stand in a similar relation to one another as a series of generations of unicellular organisms arising by a continued process of cell-division."
Those who accept evolution insist on unbroken physical continuity between the earliest known life and ourselves, so that we both are and are not personally identical with the unicellular organism from which we have descended in the course of many millions of years, exactly in the same ways as an octogenarian both is and is not personally identical with the microscopic impregnate ovum from which he grew up.
We do not mean, of course, that the egg existed from the first as a bird's egg, but as an indifferent amoeboid cell of the simplest character. The egg lived for thousands of years as an independent unicellular organism, the Amoeba.
Word Of The Day
Others Looking