How did scientist use changes in organisms living on the planet to create the geologic time scale

The scientists have used the common historical and functional basis of living organisms to create the geological time period.

Explanation:

All the living things present on earth have gone through the evolutionary process. According to the researches, the oldest fossil found on the earth can be traced 3.5 to 3.7 billion years back, and life today on earth has been evolved from a common ancestor through natural selection or adaptions.

The geological time period shows all the changes in living organisms in different eras eons,  eras, periods, epochs.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.