Cenozoic Era

Definition

The Cenozoic Era is the most recent geological era, spanning from about 66 million years ago to the present day. It is characterized by the emergence and evolution of mammals and birds, as well as significant changes in the Earth's climate and ecosystems. This era is often referred to as the 'Age of Mammals' due to the dominance of mammals in various habitats following the mass extinction event that marked the end of the Mesozoic Era.

5 Must Know Facts For Your Next Test

1. The Cenozoic Era is divided into three main periods: Paleogene, Neogene, and Quaternary, each reflecting major developments in Earth's biological and climatic history.
2. During this era, mammals evolved into many forms, ranging from small rodents to large whales, filling ecological niches that were vacated after the dinosaurs' extinction.
3. The Cenozoic also witnessed significant tectonic activity, leading to the uplift of mountain ranges such as the Himalayas and changes in ocean currents that impacted global climate.
4. Floral diversity increased during the Cenozoic, with angiosperms (flowering plants) becoming dominant and creating new habitats for animals.
5. The last part of the Cenozoic, the Quaternary Period, has seen the rise of humans and significant impacts on ecosystems due to human activity and climate change.

Review Questions

• How did the extinction event at the end of the Mesozoic Era influence the evolutionary trajectory of mammals during the Cenozoic Era?
  • The extinction event at the end of the Mesozoic Era led to a dramatic reduction in biodiversity, particularly among reptiles. This opened up ecological niches that mammals could exploit, allowing for their rapid diversification and evolution into various forms. As mammals adapted to different environments, they began to dominate terrestrial ecosystems, leading to their prominence throughout the Cenozoic Era.
• Evaluate how tectonic activities during the Cenozoic Era contributed to changes in climate and biodiversity.
  • Tectonic activities during the Cenozoic Era played a crucial role in shaping global climates and biodiversity. The uplift of mountain ranges like the Himalayas affected wind patterns and ocean currents, which in turn influenced temperature and precipitation distributions. These geological changes contributed to habitat diversity and allowed for new species to evolve or migrate, thereby enhancing biodiversity across various ecosystems.
• Synthesize the effects of human activity during the Quaternary Period on ecosystems within the context of the Cenozoic Era.
  • Human activity during the Quaternary Period has significantly impacted ecosystems established during the earlier Cenozoic Era. As humans spread across various continents, they altered landscapes through agriculture, urbanization, and industrialization. These actions have led to habitat destruction, species extinctions, and shifts in ecological dynamics. Understanding these impacts is vital as they illustrate how one species can profoundly affect Earth’s biological legacy within a relatively short geological timeframe.

Related terms

Paleogene Period: The Paleogene Period is the first of three periods in the Cenozoic Era, encompassing the evolution of early mammals and birds and a warming climate.

Neogene Period: The Neogene Period follows the Paleogene and features further diversification of mammals and the formation of modern ecosystems.

Quaternary Period: The Quaternary Period is the most recent period within the Cenozoic, marked by the rise of humans and significant climatic changes, including ice ages.