Cenozoic

Definition

The Cenozoic is the most recent geological era, spanning from about 66 million years ago to the present day. This era is characterized by significant changes in the Earth's climate, biodiversity, and landforms, leading to the dominance of mammals and birds. The Cenozoic is divided into three periods: the Paleogene, Neogene, and Quaternary, which encompass major evolutionary and geological events.

5 Must Know Facts For Your Next Test

1. The Cenozoic began after the mass extinction event that wiped out the dinosaurs and many other species at the end of the Mesozoic era.
2. This era has seen major climatic shifts, including periods of warming and cooling, which have influenced species evolution and migration patterns.
3. Mammals became the dominant terrestrial animals during the Cenozoic, leading to a vast array of species adapted to different environments.
4. The Cenozoic is marked by significant tectonic activity, including the uplift of mountain ranges like the Himalayas and changes in ocean currents that shaped global climate patterns.
5. Human ancestors first appeared during the late stages of the Cenozoic, specifically in the Quaternary period, leading to significant cultural and technological developments.

Review Questions

• How did the end of the Mesozoic era set the stage for the evolutionary developments seen in the Cenozoic?
  • The end of the Mesozoic era was marked by a mass extinction event that eliminated approximately 75% of Earth's species, including all non-avian dinosaurs. This created ecological niches that allowed mammals to diversify and thrive in a world without their former competitors. The changes in climate and habitat during the early Cenozoic facilitated this rapid evolutionary change, setting up conditions for mammals to become the dominant land animals.
• Discuss how tectonic activity during the Cenozoic has influenced both climate and biological diversity on Earth.
  • Tectonic activity during the Cenozoic has played a crucial role in shaping Earth's climate and biological diversity. The uplift of mountain ranges such as the Himalayas affected atmospheric circulation patterns, resulting in climatic changes that have driven evolution. The formation of land bridges also facilitated migrations of species between continents, allowing for increased genetic diversity as species adapted to new environments. These geological processes have significantly impacted biodiversity throughout this era.
• Evaluate how human evolution during the Quaternary period of the Cenozoic has affected our understanding of environmental changes and biodiversity.
  • Human evolution during the Quaternary period has brought a new dimension to our understanding of environmental changes and biodiversity. As humans developed technology and settled in diverse environments, they became a significant force shaping ecosystems through activities like agriculture and urbanization. This impact has led to both habitat destruction and conservation efforts, prompting scientists to study how human actions contribute to biodiversity loss and climate change. Understanding these relationships is essential for addressing current environmental challenges.

Related terms

Paleogene: The first period of the Cenozoic era, lasting from about 66 to 23 million years ago, marked by the diversification of mammals and the development of modern flora.

Neogene: The second period of the Cenozoic era, lasting from about 23 to 2.6 million years ago, characterized by further evolution of mammals and birds as well as significant geological changes.

Quaternary: The most recent period of the Cenozoic era, starting around 2.6 million years ago and continuing to the present, known for its glacial-interglacial cycles and the emergence of humans.