Jaina Biology

Author(s): J C Sikdar
Publisher: L D Indology Ahmedabad

Page 250

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Aesxual and Sexual Reproduction
celled embryo indicating that the egg cell splits or divides. This division called mitosis in modern Biology is “accompanied by a complicated series of processes within the nucleus and cytoplasm of the cells. 7
Blastula Formation :
As the cells undergo further division, a spherical mass) Kalalam, abbuyam pesi, ghanam, palam, etc.) is formed; in the centre of it a cavity appears as it is suggested by the reference to the additional cleavages until finally the embryo consists of several hundred cells, arranged in the form of a hollow ball (arbuda or pinda)8/a from which differnt organs develop. At this stage the embryo is called a blastula by Modern Biology. 9
Gastrulation :
It is suggestive from the mention of the successive stages of development of parts of the body of the embryo“Kalalam, abbuyam, pesi, ghaṇaḥ, palam, pimda, pāņi, pāyam, siram, pitta, soņita, sirā, pesisayaim, navadhamani, romakupa, kesa, maṁsu.10” etc. that almost as soon as the single-layered blastula is formed, it begins to change into a double-layer gastrula. “In simple, isolecithal eggs gastrulation occurs by the pushing (invagination) of a section of one wall of the blastula.11 “The pushed-in wall eventually meets the opposite wall so that the original blastocoele is obliterated. The new cavity of the gastrula is known as the archentteron (meaning primitive gut), because it forms the rudiment of what is to become the digestive system. This opens to the outside by the blastopore, which marks the place where the indentation for gastrulation began. The formation of the two-layered embryo is accompanied by rapid growth and division of the cells, and the resulting gastrula has about the same diameter and shape as the blastula from wbich it came. The outer of the two walls of the gastrula is called the ectoderm (outer skin); it eventually gives rise to the skin and nervous system. The inner wall, lining the archenteron, is known as the entoderm (inner skin); it finally becomes the digestive tract and its outgrowths-the liver, lungs and pancreas."12 6. Tandula Veyaliya 2, p. 6. 7. Biology, p. 431. 8. Tandula Veyaliya 2. p. 6 8/a Ibid, 7, p. 6.
Pamcame māse pamca pimdiyão pāņain payam siram ceva nivvattei" 9. Modern Biology, p. 431, 10. Tandula Veyaliya, 2, p. 6. 11. Biology, p. 431-432. 12. Biology p. 431-432