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Sep 5, 1200
The Birth Of Earth
Once upon a time, many, many years ago, the giant planets in our solar system took different paths around the sun than they follow now. Jupiter, Saturn, Uranus, and Neptune were once bunched together and closer to the sun, says an international team of scientists. Under the influence of gravity, the planets broke out of their original orbits and began violently rearranging the outer solar system. A new theory suggests that the four giant planets -
Dec 24, 1519
Mississippi period
mississip period occured like 600 years ago. it starrted back in the early 1500s.that is a long time ago. -
Dec 19, 1529
Cambrian
The Cambrian explosion, a burst of animal diversity in the fossil record about 541 million years ago, preserved ancient animals like these. Credit: Smithsonian Institution, courtesy of Douglas Erwin In your family, it’s easy to figure out whom you’re related to. Siblings share parents, cousins share grandparents and great-grandparents and so on. Go back far enough in time and you’ll discover that you share ancestors with every person on Earth -
Dec 31, 1559
Paleocene
Although the underlying causes are unclear, some authorities associate the PETM with the sudden release of methane hydrates from ocean sediments (see methane burp hypothesis) triggered by a massive volcanic eruption. The onset of the PETM was rapid, occurring within a few thousand years, and the ecological consequences were large, with widespread extinctions in both marine and terrestrial ecosystems. Sea surface and continental air temperatures increased by more than 5 °C (9 °F) during the trans -
Dec 22, 1568
Silurian
a Silurian deposit preserving a marine biota18 in unusual three-dimensional detail. The specimen is reconstructed three-dimensionally through physical–optical tomography19. Phylogenetic analysis indicates that this and many other palaeoloricate chitons are crown-group aplacophorans. -
Ordovician
The Ordovician Period lasted almost 45 million years, beginning 488.3 million years ago and ending 443.7 million years ago.* During this period, the area north of the tropics was almost entirely ocean, and most of the world's land was collected into the southern supercontinent Gondwana. Throughout the Ordovician, Gondwana shifted towards the South Pole and much of it was submerged underwater. -
Devonian
in geologic time, an interval of the Paleozoic Era that follows the Silurian Period and precedes the Carboniferous Period, spanning between about 416 million and 359.2 million years ago. The Devonian Period is sometimes called the “Age of Fishes” because of the diverse, abundant, and, in some cases, bizarre types of these creatures that swam Devonian seas. Forests and the coiled shell-bearing marine organisms known as ammonites first appeared early in the Devonian. Late in the period the first f -
Pensylavania period
The Pennsylvanian Period lasted from 320 to 286 million years ago. During the Pennsylvanian Period, widespread swamps laid down the thick beds of dead plant material that today constitute most of the world's coal -
Permian
both the last stage of the Guadalupian Epoch and throughout the Lopingian Epoch, each apparently more severe than the previous one, extended over about 15 million years. Disruptive ecological changes eventually reduced marine invertebrates to crisis levels (about 5 percent of their Guadalupian maxima)—their lowest diversity since the end of the Ordovician Period. The final extinction episode, sometimes referred to as the terminal Permian crisis, while very real, took 15 million years to material -
Triassic
In many ways, the Triassic was a time of transition. It was at this time that the world-continent of Pangaea existed, altering global climate and ocean circulation. The Triassic also follows the largest extinction event in the history of life, and so is a time when the survivors of that event spread and recolonized -
Jurassic
Land plants abounded in the Jurassic, but floras were different from what we see today. Although Jurassic dinosaurs are sometimes drawn with palm trees, there were no palms or any other flowering plants — at least as we know them today — in the Jurassic. Instead, ferns, ginkgoes, bennettitaleans or "cycadeoids," and true cycads — like the living cycad pictured above, lower left — flourished in the Jurassic. Conifers were also present, including close relatives of living redwoods, cypresses, pine -
Cretaceous
The Cretaceous is usually noted for being the last portion of the "Age of Dinosaurs", but that does not mean that new kinds of dinosaurs did not appear then. It is during the Cretaceous that the first ceratopsian and pachycepalosaurid dinosaurs appeared. Also during this time, we find the first fossils of many insect groups, modern mammal and bird groups, and the first flowering plants. -
Precambrian Time
Precambrian time covers the vast bulk of the Earth's history, starting with the planet's creation about 4.5 billion years ago and ending with the emergence of complex, multicelled life-forms almost four billion years later.The Precambrian is the earliest of the geologic ages, which are marked by different layers of sedimentary rock. Laid down over millions of years, these rock layers contain a permanent record of the Earth's past, including the fossilized remains of plants and animals buried whe -
Eocene
The Eocene is the second of five epochs in the Tertiary Period — the second of three epochs in the Paleogene — and lasted from about 55.8 to 33.9 million years ago.* The oldest known fossils of most of the modern orders of mammals appear in a brief period during the early Eocene and all were small, under 10 kg. Both groups of modern ungulates, Artiodactyla and Perissodactyla, became prevalent mammals at this time, due to a major radiation between Europe and North America -
Oligocene
The Oligocene Epoch, right smack in the middle of the Tertiary Period (and end of the Paleogene), lasted from about 33.9 to 23 million years ago.* Although it lasted a "short" 11 million years, a number of major changes occurred during this time. These changes include the appearance of the first elephants with trunks, early horses, and the appearance of many grasses — plants that would produce extensive grasslands in the following epoch, the Miocene. -
Holocene
Another name for the Holocene that is sometimes used is the Anthropogene, the "Age of Man." This is somewhat misleading: humans of our own subspecies, Homo sapiens, had evolved and dispersed all over the world well before the start of the Holocene. Yet the Holocene has witnessed all of humanity's recorded history and the rise and fall of all its civilizations. Humanity has greatly influenced the Holocene environment; while all organisms influence their environments to some degree, few have ever -
Pilocene
Pliocene, 5.3 to 2.6 million years ago,* was a time of global cooling after the warmer Miocene. The cooling and drying of the global environment may have contributed to the enormous spread of grasslands and savannas during this time. The change in vegetation undoubtedly was a major factor in the rise of long-legged grazers who came to live in these areas. -
Miocene
The Miocene Epoch, 23.03 to 5.3 million years ago,* was a time of warmer global climates than those in the preceeding Oligocene or the following Pliocene and it's notable in that two major ecosystems made their first appearances: kelp forests and grasslands. The expansion of grasslands is correlated to a drying of continental interiors as the global climate first warmed and then cooled. -
Big Bang
This image represents the evolution of the universe over its 13.7 billion years. Time increases from left to right, starting from the period of inflation to the present day. Source: WMAP team/NASA How old is the universe? Ask a cosmologist, and you’ll probably learn that the universe was born with the Big Bang about 13.7 billion years ago. (Cosmologists study the age of the universe.) At the time of the Big Bang, the universe, then smaller than -
Pleistoene
The Pleistocene also saw the evolution and expansion of our own species, Homo sapiens, and by the close of the Pleistocene, humans had spread through most of the world. According to a controversial theory first proposed in the 1960s, human hunting around the close of the Pleistocene caused or contributed to the extinction of many of the Pleistocene large mammals. It is true that the extinction of large animals on different continents appears to correlate with the arrival of humans, but questions
