Question-What is strobilation?
Answer:- Strobilation or transverse fission is a form of asexual reproduction consisting of the spontaneous transverse segmentation of the body. It is observed in certain cnidarians andhelminths. This mode of reproduction is characterized by high offspring output, which, in the case of the parasitic tapeworms, is of great significance.
Strobilation starts with some morphological changes (i.e. reabsorbing of gonads) as well as neck formation. Simultaneously, constrictions occur in the neck formation and the number of constrictions increases, transforming the body into a series of small, equal-sized segments. The cnidarian's segmentation releases new, juvenile polyps called ephyras. Jellyfish, for example, reproduce via strobilation (6 AS). Medusae primarily reproduce sexually by producing gametes (sex cells). A male medusa gamete (sperm cell) fuses with a female medusa gamete (egg cell) to form a zygote. The zygote develops into a larva which then grows to be an adult medusa. Medusae can also reproduce through such asexual mechanisms as budding (10 MB).
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Strobilation in helminths
Regarding presence of aliens :
ReplyDeleteMohit has left a new comment on your post "Ask Me":
Well i'm not the correct person to answer, but as i know something about it i would like to answer.
As earth is a part of solar system, and our sun is a part of Milky Way, there may exist as many no. of such galaxies with great no. of suns(Stars) and there respective planets.
So there must be atleast a few planets in this whole universe which should be having life on it.
so there a cent percent chances of having aliens around us.
and about there nature and classifications, they may be like us or some organism of earth or something very new to presently known science.
No one knows about the surroundings in which they must be surviving so its basically worthless to describe their species or something about which you know almost nothing..............!
Posted by Mohit to Life Science Teacher at 17 July 2012 22:18
Thanks Mr Mohit for very valuable and elaborate response.
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Holandric
DeleteHolo : complete andric : related to male.
(Science: genetics) refers to genes that are transmitted solely through male descent, in humans, holandric genes are located on the y chromosome.