In the long geological history of the Earth, humans first appeared during the Pleistocene Epoch, which dates back 1.6 million years to 10,000 years ago. Humans in modern form arrived during the Pleistocene Epoch, although human-like creatures appeared in the period just before the Pleistocene, called the Pilocene Epoch, which dates back 5 million years ago to 1.6 million years ago.Know More
The Pleistocene Epoch gave rise to many types of plants and animals on Earth in addition to humans. Species emerging during that time include the woolly mammoth, conifers, mosses and many types of insects. Remains of the woolly mammoth trace its origins back to the cold northern regions of Russia. The mammoth survived the Pleistocene Epoch, but ultimately faced extinction. Many plants and trees emerging during that time showed resilience, however.
The Pleistocene Epoch ushered in life forms including large mammals and birds. Saber-toothed tigers, ground sloths, bison, horses and camels arose during this time. Many birds, including raptors and teratorn birds, which boasted wingspans exceeding 25 feet also can be traced to this period.
Many species of plants and animals enjoyed growth during the Pleistocene Epoch. This includes humans, whose populations spanned much of the world by the end of that epoch.Learn more about Geology
Erosion affects the environment by stripping away top soil on agricultural land, damaging delicate coastal areas, causing health problems in humans and contaminating bodies of water with sediment that can harm plant and animal life. Erosion damages farm land by removing nutrient-rich soil needed to grow plants and by exposing lower-quality soil. It also damages crops and causes greater runoff of needed water.Full Answer >
Although the exact cause of ice ages is not known, scientists speculate that they are caused by a combination of the distance of the Earth from the Sun, the position of the continents and solar output. The last ice age happened around 20,000 years ago.Full Answer >
Gabbro, a type of intrusive igneous rock, is formed when magma cools and solidifies inside the crust of the Earth. Because it cools slowly, it is coarsely grained.Full Answer >
A fine-grained igneous rock is a rock that is formed by melted magma cooling so quickly at the surface of the Earth that only tiny crystals form, most too small to be seen with the naked eye. Basalt is an example of such a rock.Full Answer >