The human have first appeared during the Quaternary period that covers the time from about 2.6 million years to the present. It is comprised of the Pleistocene and the Holocene epoch.
The species 'Homo erectus' first appeared in Africa in the beginning of this period, and they gradually have undergone evolution, thereby forming bigger brains and also enhanced in terms of intelligence. The very first modern humans have evolved in Africa some 190,000 years ago and they scattered to the various regions of Europe as well as Asia. They further migrated to Australia and America.
During this course of evolution, life has drastically changed in both terrestrial and aquatic ecosystems. This period also provided the required factors for a better existence of living organisms.
