Spain butted France , and the Pyrenees rose. The high mountains altered air circulation and weather patterns, contributing to the drier and cooler climate. The Arctic ice cap grew and thickened. Snow and ice fell on the high mountains, locking up water far from the oceans. Sea levels plummeted, exposing land bridges between Africa and Eurasia and between Eurasia and North America. 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.
As the climate changed, many of the great forests that carpeted the continents from shore to shore and from Pole to Pole slowly gave way to grasslands , a habitat more suited to the cooler and drier weather. But that hardiness came with less nutrition. Plant-eating animals had to adapt in order to survive. 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.
The somewhat confusing terminology and disagreement amongst geologists on where to draw what hierarchical boundaries, is due to the comparatively fine divisibility of time units as time approaches the present, and due to geological preservation that causes the youngest sedimentary geological record to be preserved over a much larger area and to reflect many more environments, than the older geological record.
By dividing the Cenozoic Era into three arguably two periods Paleogene, Neogene, Quaternary instead of 7 epochs, the periods are more closely comparable to the duration of periods in the Mesozoic and Paleozoic eras.
The ICS once proposed that the Quaternary be considered a sub-era sub-erathem of the Neogene, with a beginning date of 2. Thus the Neogene Period ends bounding the succeeding Quaternary Period at 2. Note : The above story is based on materials provided by Wikipedia.
Friday, November 12, Sign in. Forgot your password? Get help. Password recovery. Geology Page. Home Latest News Video. Debris Flow Dynamics. Sampling Hot Molten Lava. It was followed by a long cool, dry period.
The current global warming event has been set off primarily by human activity. Each segment of the Cenozoic experienced different climates. The Neogene period saw a drastic cooling, which continued into the Pleistocene epoch of the Quaternary period. As for the changing landscape, the continents drifted apart during the Paleogene period, creating vast stretches of oceans. This had a significant impact on the climate and marine life surrounding each continent.
During the Pleistocene epoch, glaciers covered central North America, extending as far east as New York, south to Kansas and Nebraska and west to the northern West Coast.
The Great Lakes were formed as the glaciers receded. The Cenozoic era is also known as the Age of Mammals because the extinction of many groups of giant mammals, allowing smaller species to thrive and diversify because their predators no longer existed. They are called ruminants. They were efficient at getting nutrients from the grasses. This new type of animal, the artiodactyl, developed into many familiar species: camels, bison, sheep and giraffes, to name a few.
New predators evolved for the grassland environments of the Neogene Period. The grazing animals could run fast. Predators had to adapt or go hungry. The sleek bodies of the dog and cat carnivores were able to run fast and use their powerful jaws and teeth to take down their prey. They became the dominant predators in the Miocene grasslands.
There was new plant growth in the oceans, too. Kelp is a form of large brown algae. Kelp forests grew in cool waters where the plant could attach to rocks and coral. Otters and other animals evolved to live in this unique ecosystem. The dugong, a marine mammal related to the elephant and modern manatees, lived in large numbers in the Miocene kelp forests.
Modern versions of these animals still feed on the plants in the Great Barrier Reef off the Australian coast. Sharks developed new species. One of these new sharks was Charcharodon Megalodon.
It appeared first in the Miocene Epoch about 16 million years ago. Megalodon was the largest of all the sharks. It grew to be nearly 50 feet long! To feed its huge body Megalodon dined on whales and dugongs.
Megalodon became extinct about 1. The cooling climate of the Paleogene Period continued into the Neogene Period. By the end of the Pliocene Epoch the earth was locked in an Ice Age. There were many reasons that this happened. The lower sea levels, new mountains and shifting ocean currents all contributed.
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