During sexual reproduction, a young individual develops as a result of the fusion of two germ cells.
During sexual reproduction, a young individual develops as a result of the fusion of two germ cells. However, in the cells of the offspring, the number of chromosomes does not increase, but remains constant. Explain why the number of chromosomes in cells does not increase with each generation?
1) Sex cells (gametes) are always formed as a result of meiosis (otherwise it is called reduction division). As a result, cells with a single (or haploid) set of chromosomes (n) are formed.
2) During sexual reproduction, gametes merge (this process is called fertilization). Due to this, the restoration of the diploid set (2n) of chromosomes occurs in the zygote. Because of this, the number of chromosomes in each generation remains constant (with the exception of various mutations, in which there is an increase or decrease in the number of chromosomes).