Paleogene (66 - 23 million years ago):
* Mammals: This was a time of incredible diversification for mammals, filling ecological niches previously occupied by dinosaurs. Key groups include:
* Primates: Early ancestors of monkeys, apes, and humans emerged.
* Whales: Adapted to marine life.
* Hoofed mammals: Horses, rhinoceroses, and other herbivores diversified.
* Carnivores: Cats, dogs, and bears began to evolve.
* Birds: Continued to evolve and diversify, with some groups like the extinct giant flightless birds (e.g., Diatryma) being quite prominent.
* Marine Life: Sharks, rays, and bony fish were abundant.
Neogene (23 - 2.6 million years ago):
* Mammals: Continued diversification and evolution.
* Hominins: Early human ancestors emerged and evolved.
* Grazing mammals: Horses, elephants, and others became prominent due to the spread of grasslands.
* Large predators: Saber-toothed cats, giant bears, and other large carnivores roamed the land.
* Birds: More modern bird groups began to emerge.
* Marine Life: Continued similar to the Paleogene, but with some new species evolving.
Important Note: The Tertiary period is not officially used in modern geological classification. It has been replaced by the Paleogene and Neogene periods, which are considered more accurate representations of the Earth's history.
To summarize:
The Tertiary period was a time of explosive evolution for mammals, with various groups diversifying and filling ecological niches. Birds continued to evolve, and marine life remained abundant. This period saw the rise of many iconic creatures that have shaped our understanding of life on Earth.
