Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 27, 2025
But in Volvox a division of labor has been effected of such a nature that most of the components discharge the tasks of individual value, and with the performance of these they die. Only the reproductive members are immortal in the sense that Amoeba is, for they only have a place in the chain of consecutive generations of Volvox colonies.
This embryo, resembling a hollow rubber ball filled with fluid, is called a blastosphere. It corresponds in structure with the fully developed volvox, except, of course, in lacking reproductive cells. If the rubber ball has a hole in it so that I can squeeze out the water, I can thrust the one-half into the other, and change the ball into a double-walled cup.
The caterpillar larva devotes all of its energies to feeding and growing, unconcerned with the final duties of the moth with which it is connected just as the indifferent unit of a young Volvox colony is related to a reproducing member of the full-grown organism.
The methods of fissive multiplication and of conjugation observed in the monads of this locomotive globe are essentially similar to those observed in Chlamydomonas; and, though a hard battle has been fought over it, Volvox is now finally surrendered to the Botanists.
The germ of a higher animal a mammifer, for instance is the representative of a lower animal full-grown, like the volvox globator; the latter remaining in this initial stage, as an animalcule, through its whole existence; while the former is developed out of it, by successive stages, into a quadruped, or even into a man.
In explaining the facts of reproduction, I would therefore suggest that you should begin with the lowest rung of the ladder, the simplest organisms, such as the amoeba or the volvox. I should show how these multiply by fission, the creature dividing into two, when it is impossible to tell which is the father and which is the mother.
Insects impregnated for six generations. Polypus branches like buds. Creeping roots. Viviparous flowers. Tænia, volvox. Eve from Adam's rib. Semen not a stimulus to the egg. Embryons not originally created within other embryons. Organized matter is not so minute. 2. All the parts of the embryon are not formed in the male parent. Crabs produce their legs, worms produce their heads and tails.
Volvox may be compared to a hollow sphere, the wall of which is made up of coherent Chlamydomonads; and which progresses with a rotating motion effected by the paddling of the multitudinous pairs of cilia which project from its surface. Each Volvox-monad, moreover, possesses a red pigment spot, like the simplest form of eye known among animals.
And, in fact, there are some green organisms, in every respect characteristically plants, such as Chlamydomonas, and the common Volvox, or so-called "Globe animalcule," which run through a cycle of forms of just the same simple character as those of Heteromita.
And plants and animals are here so near together, and travelling by roads so nearly parallel, that, even if volvox never was an animal, it might still serve very well to illustrate a stage through which animals must have passed. The cells of volvox do not form a solid mass, but have arranged themselves in a single layer on the outer surface of the sphere.
Word Of The Day
Others Looking