Project for eras and evolutionary.. Please answer!?

Question

We have to answer the following questions:

What era has the most new life forms?

Which era is the longest? Why is this era so much longer than the others?

How many times longer is the Precambian than the Paleozoic?

Does it make sense to divide the Precambian era into 2 eras? If so, where would you draw the divison line?


I think I know the answers but I'd just like some other responses to get different ideas about it. Thanks so much if you answer!

Answer 1

What era had the most new life forms? Probably the Paleozoic Era. Of the three eras in the Phanerozoic, the Paleozoic is the longest. I don't know much about the eras before the Phanerozoic, so I can't answer outside the Phanerozoic. The Paleozoic lasted from 570 to 230 million years ago, making it 340 million years long. The Paleozoic started when the Earth was 3900 million years ago. 3900/340=11.47, so Precambrian time was over eleven times longer than Paleozoic time. No, it does not make sense to divide the Precambrian into 2 eras. In fact, the Precambrian is an outdated term, although it is still in widespread use among geologists. The most fundamental division of Earth time is the Eon, and there are four of them: The Hadian Eon-0.0 to 0.6 Ga (Giga-annum or billion years), the Archeozoic Eon-0.6 to 2.5 Ga, the Proterozoic Eon, 2.5 to 3.9 Ga, and the Phanerozoic Eon, 3.9 to 4.5. Some of the dates might be off, but they are essentially correct. There are periodic revisions that refine these dates. Also, I am putting down this information for my memory, not from a book or web site.