Vegetation and Organism/animals

This post will be completly dedicated to the Vegetation and Animal Life of the Neogene Era. As we explained in our last post, grasses appeared at the beginning of the Miocene and quickly replaced the thinning forests. But grasses are poor fodder: tough, low in nutrients, high in tooth-destroying silicates. They die back to their roots in cold weather. Under the triple hammers of drought, starvation and cold, herbivorous species were smashed or utterly changed. Their predators followed them into extinction or transformation. The later Neogene saw the creation of an entirely new guild of hunters, the pursuit predator, able to follow scarce prey across miles of open country rather than waiting for the easier opportunity which might never come. The pursued developed their own responses: herd behaviors, seasonal migrations, and big bodies, adapted for speed and endurance.

Another line of adaptation led to small-bodied generalists -- rodents, raccoons, rabbits, and possums -- and their predators, the foxes, cats, dogs and snakes. These generalists were mainly unspecialized herbivores or omnivores, with partially fossorial habits, strong territoriality and high reproductive rates. Theirs was the ability to exploit many resources within small, locally or temporarily favorable conditions, excluding competition and using rapid reproduction as a defense to predation, to quickly take new territory, or to recover from local disasters. These organisms often developed seasonal torpor as a method for surviving seasonal extremes.

A few species do not fall neatly into any of these categories. Humans are one. Bears are another. In one sense, these are hyper-generalists, able to use a wide repertoire of behavioral adaptations to compensate for a conspicuous absence of genetically-endowed talents. In another sense, they are throw-backs to a style of life more common in the Paleogene or the Late Mesozoic. The survival of this group is hard to explain, with so many other, robust lineages disappearing. The continental connections gave animals that had evolved in isolation access to new lands. Elephants and apes wandered from Africa to Eurasia. Rabbits, pigs, saber-toothed cats, and rhinos went to Africa. Elephants and rhinos continued across the Bering Strait to North America. Horses went the other way. Ground sloths migrated from South America to North America; raccoons scurried south. Even rodents may have hopped Pacific islands en route to Australia from Southeast Asia.

Horses evolved stronger, enamel-protected teeth and flourished. So too did ruminants such as bison, camels, sheep, and giraffes, whose compartmentalized stomachs are well adapted to digesting grass. Many of the grazers were quick and roamed in herds—new tricks for survival out in the open. Their predators were also forced to adapt.

In the oceans, a new type of large brown algae, called kelp, latched onto rocks and corals in cool shallow waters, establishing a new habitat favored by sea otters and dugongs, a marine mammal related to the elephant. Sharks grew and dominated the seas once again. Megalodon, the biggest shark of all, was nearly 50 feet (15 meters) long.

On land, Asian and African apes diverged and then, several million years later, hominins split from their closest African ape ancestors, the chimpanzees. Adapted to two-footed walking, early hominins dropped out of the trees and started to carry food and tools in their hands. These new species were poised to alter the planet unlike any other in the centuries to come.