Question

Zygotic meiosis occurs in
A. Pinus
B. Marchantia
C. Dryopteris
D. Chlamydomonas

Answer 1

Meiosis is a special type of cell division which results in reduction of cells. It generally takes place in growth cells of sexually reproducing organisms to produce gametes such as sperm or egg cells. It involves stages one in which the parental characteristics take place.

Complete answer:
Zygotic meiosis occurs in chlamydomonas. When the zygote divides meiotically or when zygote undergoes reduction division after division of nucleus i.e. after karyogamy it is called as zygotic meiosis. Zygote is a stage that is formed after fertilization. The fusion of male and female gametes is called fertilization. Fertilization is of two types:
(a) Internal fertilization: When the fertilization takes place inside the body of an organism, it is called internal fertilization.
(b) External fertilization: When the fertilization takes place outside the body of an organism it is called as external fertilization. Zygotic meiosis mainly occurs in haploid organisms. When there is a single set of chromosomes, it is restored as a haploid set and when the set of chromosomes, it is restored as a haploid set and when the set of chromosomes is doubled it is called diploid set. Zygotic meiosis occurs in organisms with a single set of chromosomes.
Example: Chlamydomonas, focus.

Therefore, the correct option is (D) Chlamydomonas.

Note: Zygotic meiosis is a characteristic feature of haploid organisms and cannot take place in diploid or haplodiplontic organisms or organisms with alternate life cycle. Dryopteris and pinus show haplodiplontic life cycle and marchantia show alternate haploid diploid generation.