A Brief Overview of the Cenozoic Era for Middle School Science Classes

Dec 5, 2024

3 min read

Earth history is a fascinating topic! It is also a massive topic! The reading passage below will teach you all about the Cenozoic Era. If you want to learn more (and why wouldn't you?!), you can check out my Earth History page. I also have all of my passages available at Teachers Pay Teachers. They come with so many extras to get your students thinking about the content! I also recommend scrolling to the bottom of the page to check out my digital picture book on the Cenozoic Era!

The Cenozoic era is the most recent era in Earth’s history. We are currently living in the Cenozoic era.

Cretaceous Extinction Event

The Cenozoic era began after the mass extinction event at the end of the Cretaceous period of the Mesozoic era. During the Mesozoic era, dinosaurs had dominated the Earth’s environments. When a giant meteor struck the Earth, an ash cloud blocked out the Sun for nearly two years. Without sunlight, the plants died. The herbivores that ate the plants died. The carnivores that ate the herbivores died.

Mammals

Mammals had coexisted with the dinosaurs for millions of years as small rodents. These early mammals survived the Cretaceous extinction event because they were small and would eat anything. When the environment recovered from the meteor, mammals no longer had to compete with massive dinosaurs for resources. Birds, reptiles, fish, and insects also thrived in the post-dinosaur world.

Humans

Early humans first evolved during the Pliocene epoch. The earliest humans were Australopithecines. Fossils of Australopithecines found in Africa are over four million years old. Other species of humans evolved throughout the Pliocene and Pleistocene epochs. Homo sapiens, or modern humans, evolved around two hundred thousand years ago.

Humans had an immediate effect on the environment. Scientists believe overhunting was one cause of the extinction of giant mammals such as the wooly mammoth twelve thousand years ago. Humans are still affecting the Earth today. Burning fossil fuels is adding carbon dioxide to the atmosphere. We are also destroying animal habitats. These actions could lead to a Holocene extinction event. Scientists believe up to 30 percent of the plants and animals on Earth will be extinct in the next hundred years. Luckily, humans can also help the environment. If we can learn to conserve Earth’s resources, we may be able to prevent the Holocene extinction.

Continents

Pangaea started breaking apart during the Mesozoic era. The continents have continued to separate throughout the Cenozoic era. Greenland separated from Europe, Australia separated from Antarctica, and Africa separated from India. After separating from Africa, India crashed into Asia, forming the Himalayan Mountains. The Cascade Mountains, the Alps, and the Andes also formed during the Cenozoic era. The continents haven’t stopped moving. The Mid-Atlantic Ridge in the Atlantic Ocean is pushing North America and Europe farther apart. As a result, North America and Asia will collide in about twenty million years. Eventually, a new supercontinent will form. Scientists believe the new continent will be located across the North Pole.

Climate

The climate of the Cenozoic era has been cooler than other times in Earth’s history. The Pleistocene epoch was made up of a series of ice ages. We are currently in a interglaciation period. This is a warm period between two ice ages. However, the amount of carbon dioxide in the atmosphere is raising the average temperature on Earth. A higher temperature means melting ice sheets and higher sea levels. Without human intervention, scientists believe another ice age would come within two thousand years, but this is unlikely if carbon dioxide levels remain as high as they are today.

Cenozoic Era Picture Book

Looking for another way to learn about the Cenozoic Era? Check out this picture book version. The pages are a part of my Earth History bundle on Teachers Pay Teachers.