Elements of biology, with special Elements of biology, with special reference to their rôle in the lives of animals elementsofbiolog00buch Year: 1933 ID. DIVISION OF EACH MICRONUCLEUS INTERCHANGE OF MICRONUCLEI FUSION OF MICRO- NUCLEI SEPARATION OF CONJUGANTS a I RISEOFNEW ^ MACRO NUCLEI mal into daughters, each with a portion of both macro- and micro- nucleus. The oral groove now re- appears in each of the daughter paramoecia, which are now in form identical with the original parent. The protoplasm of the animal, which before the division may be regarded as old, has by reason of the chang
Elements of biology, with special Elements of biology, with special reference to their rôle in the lives of animals elementsofbiolog00buch Year: 1933 ID. DIVISION OF EACH MICRONUCLEUS INTERCHANGE OF MICRONUCLEI FUSION OF MICRO- NUCLEI SEPARATION OF CONJUGANTS a I RISEOFNEW ^ MACRO NUCLEI mal into daughters, each with a portion of both macro- and micro- nucleus. The oral groove now re- appears in each of the daughter paramoecia, which are now in form identical with the original parent. The protoplasm of the animal, which before the division may be regarded as old, has by reason of the changes that occur during divi- sion become the protoplasm of young animals. The restoration of the properties of young protoplasm to protoplasm which has become aged is called rejuvenescence. Conjugation. The paramoecium is apparently capable of continuing to divide in this fashion indefinitely so long as the conditions in which it lives are suitable. However, more often the rate of division slows down after a time and is restored after an interchange of nuclear ma- terial between two individuals takes place, a process that is essentially sexual and undoubtedly is compa- rable to the fertilization process in higher animals. This process is called AMPHIMIXIS. It is effected as Fig. 21.—Scheme representing the con- jugation of two paramoecia. Note the dis- appearance of the macronuclei, the repeated divisions of the micronuclei, and the inter- change of micronuclei.
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