<span>Humans first appeared during the Quaternary period. <span>The Quaternary or Neozoic period develops in the Cenozoic
era, which extends from 2,588 million years ago to the present. The
Quaternary is divided into two periods. The Pleistocene, the first and
longest period of the period, was characterized by the cycles of glaciations
and the appearance of the first humans (homos habilis); this period
extended from 2,588 million years to 10,000 years BC The Holocene, the second
epoch of the period, was characterized by the end of the glaciation and the
emergence of human civilization; this period extends from 10,000 years BC
to the present.</span></span>
