Question

1. practice: stru scale

respond to the following based on your reading.
question 1
briefly compare and contrast relative dating and absolute dating methods.
question 2
⁸⁷rb has a half - life of 47 billion years, while ¹⁴c has a half - life of 5,730 years. which isotope would you use to date a fossil from the paleozoic era? briefly explain your choice.

Explanation:

Question 1: Relative dating determines the order of events or fossils in a sequence by their position in rock layers (stratigraphy), giving a relative age. Absolute dating, on the other hand, uses radiometric techniques (like carbon - 14 or potassium - argon) to assign a numerical age to a fossil or rock. Relative dating is useful for establishing a general sequence, while absolute dating provides specific time estimates.
Question 2: The Paleozoic Era lasted from about 541 to 252 million years ago. Since $^{87}$Rb has a very long half - life of 47 billion years, it is more suitable for dating very old materials like those from the Paleozoic Era. $^{14}$C has a short half - life of 5,730 years and is better for dating relatively recent organic materials (up to about 50,000 years old). So, $^{87}$Rb should be used.

Answer:

Question 1: Relative dating orders fossils/ events by position in rock layers; gives relative age. Absolute dating uses radiometric methods for numerical age. Relative for sequence, absolute for specific time.
Question 2: $^{87}$Rb. Its long half - life (47 billion years) makes it suitable for dating old fossils from the Paleozoic Era.