The Neogene period is a geological time frame that lasted from about 23 million to 2.6 million years ago. It is divided into two epochs: the Miocene and the Pliocene. During this time, the Earth's climate became cooler and drier, leading to the expansion of grasslands and the evolution of many modern plant and animal species. This period is significant for the development of mammals and birds, as they diversified and adapted to new environments. Notable events include the rise of early humans and the formation of the Isthmus of Panama, which connected North and South America, impacting ocean currents and climate.