Final answer:
Primordial germ cells evolve from a dormant state at birth to active cells during puberty, under the influence of gonadotropic hormones. In males, they undergo spermatogenesis to create sperm, whereas in females, they become oogonia, leading to the production of eggs during the menstrual cycle.
Step-by-step explanation:
Primordial germ cells undergo significant changes over time. Initially, these cells are deposited during gestation and remain in an inactive state until adolescence. With the onset of puberty, gonadotropic hormones from the anterior pituitary gland activate them. In males, this triggers the process of spermatogenesis, where the primordial germ cells, known as spermatogonia, divide to produce primary and secondary spermatocytes, spermatids, and eventually mature sperm. This process continues well into old age.
In the context of female development, the absence of the SRY gene causes the primordial germ cells in the bipotential gonads to differentiate into oogonia, which are precursor cells to ova. These cells begin the process before birth, which halts during meiosis until puberty. When this process resumes, one egg is produced at each menstrual cycle, accompanied by polar bodies that are later reabsorbed by the body.
Whether leading to sperm or egg production, these primordial cells are crucial to human development and the continuation of our species, enabling the progression from a single-celled zygote to a complex organism made of trillions of cells organized into tissues and organ systems.