On what period did humans arrive on Earth?

Question

A. Quaternary
B. Teritary
C. Cretaceous
D. Triassic

Answer 1

God created humans on the sixth day.

Answer 2

Well this depends on what we call 'human.' The Triassic was a bit early for even humanoid type ancestors, mammals were just beginning to get a good niche established in the ecology that far back. The earliest primate ancestors date to the Cretaceous but these would be hard to call human by any stretch of the imagination no matter where their lineages led to. If you want to call some of the early bipedal hominids like Australopithecus and their ancestors humans, then we might make a case for the Teritary period. But if you describe 'humans' as the genus Homo only and we're looking at Homo erectus through Homo Sapiens then we must limit the time line to the Quaternary.
So, I'll say A. Quaternary. But, a good case could be made for most or the selections given depending on how far you want to trace back the 'human' linage.

http://news.nationalgeographic.com/news/2005/02/0216_050216_omo.html

http://en.wikipedia.org/wiki/Human_evolution

http://www.uky.edu/KGS/education/tertiary_hominid.htm

http://www.archaeologyinfo.com/homorudolfensis.htm

Answer 3

A.

The Quaternary Period is the geologic time period from the end of the Pliocene Epoch roughly 1.806 million years ago to the present. The Quaternary includes 2 geologic subdivisions — the Pleistocene, including Gelasian that used to belong to Pliocene, and the Holocene Epochs.

There is an ongoing debate of the status of Quaternary – a recent proposal from ICS was to make Quaternary a subperiod under Neogene, but that was retracted at criticism from INQUA, so instead ICS and INQUA agreed to erect Quaternary a subera, above Neogene, and to place the base for Quaternary at 2.588 ± 0.005, the base for Gelasian. However IUGS decided that Quarternary couldn't start within the epoch Pliocene thereby splitting it in two, so the decision is still awaiting settlement.[1]

The genus is estimated to be between 1.5 and 2.5 million years old. All species except Homo sapiens (modern humans) are extinct.

Answer 4

The Mesozoic Era is divided up into three periods: the Triassic, the Jurassic and the Cretaceous. Likewise, the Cenozoic Era is divided up into two periods: the Paleogene and Neogene. Tertiary and Quaternary are outdated terms, although still widely used by stubborn geologists. Humans split from our nearest simian relative (which I believe is the Orangutan) about 5 million years ago, which is clearly in the Neogene Period.

Answer 5

Humans didn't arrive here, they were born here! Either way, it's definately not C or D.

Answer 6

a

Answer 7

A.