Chapter 14, Problem 13A

Summary Introduction

To calculate:

The percentage of Earth’s existence occupied by the Cenozoic Era.

Introduction:

Fossils are the evidences for the organisms that once existed on this planet. The fossils contain clues about the organism, like feces, bone, teeth, or wood. From fossils, scientists can determine the structure and lifestyle of that organism.

Answer to Problem 13A

The percentage of Earth’s existence occupied by Cenozoic era is 1.4%.

Explanation of Solution

The most recent subdivisions of animal history are the Mesozoic era, Paleozoic era, and the Cenozoic era. The Cenozoic era is of around 65 million years.

The span of Cenozoic era is 65 million years

The age of the Erath is 4 billion years.

  $\begin{array}{c}\text{The percentage of Earth's existence occupied by Cenozoic era = }\frac{65,000,000}{4,000,000,000}\times 100\\ =1.4\%\end{array}$