Click on the button below to see evidence relevant to the question of whether or not the LDG is old.
Don't forget that a genus (plural = genera) is just a group of closely related species!
Notice that each graph shows species or genera data for a different group of organisms at a different time period. And, again, notice that data for both hemispheres is not usually available. Nevertheless, these patterns can tell us something important about the LDG over the course of Earth's history.
A. Based on the evidence presented above, do you think that the LDG is a recent phenomenon or an old one? Explain how the data above support your thinking.
B. What sort of evidence would it take for you to change your mind about this?