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The Jurassic Portal

Introduction

The Jurassic (/dʒʊˈræsɪk/ juurr-ASS-ik) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era as well as the eighth period of the Phanerozoic Eon and is named after the Jura Mountains, where limestone strata from the period were first identified.

The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province (CAMP). The beginning of the Toarcian Age started around 183 million years ago and is marked by the Toarcian Oceanic Anoxic Event, a global episode of oceanic anoxia, ocean acidification, and elevated global temperatures associated with extinctions, likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear, definitive boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined.

By the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses: Laurasia to the north and Gondwana to the south. The climate of the Jurassic was warmer than the present, and there were no ice caps. Forests grew close to the poles, with large arid expanses in the lower latitudes. (Full article...) (Full article...)

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Bacteria (/bækˈtɪəriə/ ; singular: bacterium) constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in mosthabitats on the planet. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in plants and animals and have flourished in manned space vehicles.

There are approximately 5×10³⁰ bacteria on Earth, forming a biomass that exceeds that of all plants and animals. Bacteria are vital in recycling nutrients, with many steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. In the biological communities surrounding hydrothermal vents and cold seeps, bacteria provide the nutrients needed to sustain life by converting dissolved compounds such as hydrogen sulphide and methane to energy. Most bacteria have not been characterised, and only about half of the phyla of bacteria have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. (see more...)

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Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Cope distinguished himself as a child prodigy, publishing his first scientific paper at the age of nineteen. Cope later married and moved from Philadelphia to Haddonfield, New Jersey, although Cope would maintain a residence and museum in Philadelphia in his later years.

Cope had little formal scientific training, and he eschewed a teaching position for field work. He made regular trips to the American West prospecting in the 1870s and 1880s, often as a member of United States Geological Survey teams. A personal feud between Cope and paleontologist Othniel Charles Marsh led to a period of intense fossil-finding competition now known as the Bone Wars. Cope's financial fortunes soured after failed mining ventures in the 1880s. He experienced a resurgence in his career toward the end of his life before dying in 1897.

Cope's scientific pursuits nearly bankrupted him, but his contributions helped to define the field of American paleontology. He was a prodigious writer, with 1,400 papers published over his lifetime, although his rivals would debate the accuracy of his rapidly published works. He discovered, described, and named more than 1,000 vertebrate species including hundreds of fishes and dozens of dinosaurs. His proposals on the origin of mammalian molars and for the gradual enlargement of mammalian species over geologic time ("Cope's Law") are notable among his theoretical contributions. (see more...)

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A pyritized fossil shell of the amaltheid ammonoid Pleuroceras solare. The shell dates back to the Pliensbachian age (182.7–190.8 million years ago) of the Early Jurassic epoch and is about 3.2 cm in diameter. It was collected near Little Switzerland, Germany.
Photo credit: H. Zell

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Did you know?

Illustration of a fossil Pleurosternon shell

... that, together with Platychelys, Pleurosternon is one of the few fossil genera with characteristics of both modern turtle suborders?
...that Castorocauda lutrasimilis, a recently described mammal relative that looked like an otter with a beaver's tail, evolved a semi-aquatic lifestyle 110 million years earlier than any other mammal-like animal?
... that Xinjiangtitan is a 32 metre sauropod dinosaur from Xinjiang in China?
... that the discovery of the fossil of Shenshou, a squirrel-like early mammal from the Tiaojishan Formation, pushed the origin of mammals back to the Late Triassic, 220 million to 200 million years ago?
... that Calsoyasuchus valleyceps, an extinct crocodile relative from the Early Jurassic, has a deep groove in its skull from which its species name, "valley head", derives?