Question 1. Table 1 Event Fill out Table 1 using the geologic timescale (Fig. 3): Age Geologic Time Answer 4100 million Oldest known rocks Eon? years ago 540 million Early shelled organisms Period? years ago 430 million Land Plants Period? years ago 416 million First amphibians Coal-forming swamps Period? years ago 318 million Period? years ago 175 million First birds Period? years ago Early humans 3 million years Epoch? ago