Try the problems out, then check your answer below. If an element has a half-life of twenty million years, and there is 6.25% of it remaining in a rock, how old is the rock? In a certain rock, there is 1/16th of the original parent element, and 15/16th of the daughter element.
If 1/8 of the parent material remains, that means that the rock is 3 half-lives old. 2 half-lives = 1/4 remaining, and 3 half-lives = 1/8 remaining. D is the only tree that shows that species A is more closely related to species D. True/False: Homo sapiens were the first Homo species to leave Africa. If 1 half-life is 20 million years, then 4 is 80 million years. A scientist is radiometrically dating 3 different rocks. Which of the following is evidence supporting the theory that humans share a common ancestor with apes? Our DNA is over 99% similar to that of chimpanzees b. Which of the following is a true statement about human evolution? Bipedal posture and large brain size evolved at the same time.