Final answer:
Cells lose their totipotent ability in the first few days of embryonic development as they become precursors to specific lineages. They then transition to pluripotent and later multipotent states, and eventually may become terminally differentiated with a finite lifespan.
Step-by-step explanation:
Cells lose their totipotent ability at a very early stage of embryonic development. The first embryonic cells that arise from the division of the zygote are described as totipotent because they can differentiate into any type of cell required for the organism to grow and develop. However, this totipotency is short-lived. After a few days, these cells become precursors to specific lineages of cells, which means they start to lose their totipotency and become committed to developing into more specialized cell types.
Subsequently, these cells transition to a pluripotent state, where they are capable of differentiating into any type of human tissue but cannot support the full, independent development of an organism. As the cells continue to specialize, they become multipotent, with a more restricted potential. Ultimately, they may become terminally differentiated, where they usually cease to divide and have a finite life span, needing stem cells to replenish them.