You might suggest an analogy to the way that human technological development has accelerated in recent human history. For example, the Cambrian explosion marks a vast diversification of animal and plant life, and all the other changes we’ve seen in animal species can only have happened after that. The timeline itself offers at least some evidence that evolution has accelerated in more recent times compared to the first four billion years. (1) Students should remember that the events shown on the geological time scale are based on careful study of the fossil record, which means many of the events are tied to the evolution of life.This discussion is intended to make sure students think about the relative lack of detail shown for the first four billion years before you continue on. Overall, which of the two possible reasons do you think is more likely, or do you think it was some combination of them? Defend your opinion.Based on what you have learned about rocks and fossils, identify two reasons why finding fossils from the first four billion years is much more difficult than finding them from more recent times. Now consider the second possible reason.Can you think of any reason why the number of notable events on Earth might have become greater in more recent times? Possible reason 2: A lot happened, but we don’t know very much about it compared to what we know about more recent times.ĭiscuss the following questions about these two possibilities in small groups or as a class.Possible reason 1: Not much happened during the first four billion years.Generally speaking, there are two possible reasons why scientists might have identified less detail for Earth’s first four billion years than for more recent times: Discussion Lack of Detail in Earth’s First Four Billion Years
0 kommentar(er)
