Short answers, pulled from the story.
The word Neogene was coined in 1853 by the Austrian palaeontologist Moritz Hörnes. Hörnes lived from 1815 to 1868 and introduced this new vocabulary to describe rocks deposited during the era. The term eventually replaced the older label Tertiary Period in formal geological classification.
The Neogene period ended 2.58 million years ago at the boundary of the Quaternary Period. The International Commission on Stratigraphy reached a compromise in 2009 to set this base date, effectively ending the Neogene at that precise moment. This decision resolved decades of disagreement between marine and terrestrial geologists regarding the timeline.
The formation of the Isthmus of Panama connected North and South America late in the Pliocene epoch. This massive land bridge fundamentally altered global ocean circulation by cutting off warm currents from the Pacific Ocean to the Atlantic Ocean. The event also caused sea levels to fall and created land bridges between Africa and Eurasia as well as Eurasia and North America.
The Middle Miocene brought a warm phase known as the Middle Miocene Climatic Optimum driven by the emplacement of the Columbia River Basalt Group. Around 11 million years ago this warm interval gave way to the much cooler Late Miocene, marking the beginning of a long-term cooling trend. Between 7 and 5.3 million years ago a decrease in global temperatures termed the Late Miocene Cooling ensued due to decreases in carbon dioxide concentrations.
The oceans of the Neogene were dominated by large carnivores like megalodons and livyatans. About 19 million years ago approximately 70% of all pelagic shark species disappeared in a catastrophic event that reshaped the marine ecosystem. Despite these losses marine and continental flora and fauna developed a modern appearance signaling a transition toward the ecosystems we recognize today.
The first hominins appeared near the end of the Neogene period in Africa. Homo habilis emerged as the period drew to a close while ice age mammals like the mammoths and woolly rhinoceros were common in the Pliocene. This appearance occurred in Africa where the first humans emerged as the period drew to a close.