By the late Devonian, the land had been colonized by plants and insects. In the oceans, massive reefs were built. Euramerica and Gondwana were beginning to converge into what would become Pangaea.
Tectonic and volcanic activity was high. A series of extinction events occurred towards the end of the Devonian, including a major event at the Frasnian-Famennian boundary in the Late Devonian, about 364 mya.
A major extinction occurred at the start of the last phase of the Devonian period, the Frasnian-Famennian boundary, about 372.2 mya. Almost all the fossil agnathan fishes suddenly disappeared. A second strong extinction closed the Devonian period. The late Devonian extinction was one of five major extinction events in the history of the Earth. The cause or causes are not known.
Proterozoic
The Proterozoic eon comes before the Phanerozoic. It was a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life". The Proterozoic Eon extended from 2500 million years ago (mya) to 541 mya. It is the most recent part of the former Precambrian.
The Proterozoic consists of 3 geologic eras, from oldest to youngest:
The well-identified events were:
Study of these rocks shows that the eon featured massive, rapid continental accretion (unique to the Proterozoic), supercontinent cycles, and mountain building.
Cainozoic
The Cainozoic (Cenozoic) is the current geological era. It began 66 million years ago and continues today. Before it was the Mesozoic.
During the Cainozoic the continents moved into their present positions. The climate started warm, but cooling continued steadily. Finally ice ages occurred.
The word Cainozoic is derived from Greek "kainos" = "new", and "zoe" = "life". 'Cainozoic' may be spelled 'Cenozoic'. It has three periods, and the periods are split into stages.
Previously, what is now the Cainozoic was divided into two periods, the Tertiary and the Quaternary. The Tertiary corresponded to the Palaeogene+Neogene. Now, the term 'Tertiary' is not used. Officially, it is 'deprecated'.
On land, the Cainozoic is the era of mammals, and of birds and flowering plants. Grassland became a major habitat. Aquatic mammals took over the roles of predatory reptiles like the mosasaurs and plesiosaurs. As a result, the ecological landscape of the Cainozoic has become quite different from the Mesozoic.
Bill Elliott
William Clyde Elliott (born October 8, 1955) is an American racecar driver. He drove in the Sprint Cup Series He won the 1988 Sprint Cup, and was inducted into the Motorsports Hall of Fame of America in 2007. In 2014, Elliot was voted into the NASCAR Hall of Fame. He was inducted into the Hall of Fame in January of 2015.
Dolhasca
Dolhasca is a town in southeastern Bukovina, in Suceava County, Romania. 11,000 people were living in Dolhasca as of 2002. It became a town in 2004.
Siret
Siret is a town of Suceava County in northeast Romania. The town is found on the right bank of the Siret River. Ukraine borders Siret to the north. 9,358 people were living in Siret as of 2002.
Default gateway
A default gateway is the IP address used to get out of your network.
Token passing
Token passing is a communication protocol used in telecommunications. The system uses a signal called a "token" to limit when a device can transmit on the network. Only the device with the token can transmit. When that device is done, the token is sent to the next device. With large transmissions, the token may move to the next station before the transmission is finished. The device has to wait until it gets the token back before it can continue to send data. The most well known examples of token passing are token ring and ARCNET.
The rules of the system say how long a device may keep the token, how long it can transmit for and how to create a new token if there is not one in use.
Carrier sense multiple access
Carrier Sense Multiple Access (CSMA) is a Media Access Control (MAC) protocol. When transmitting on a medium that is shared by many transmitters, the transmitter first checks to see that nothing else is already transmitting. Examples of shared transmission medium include an electrical bus, or part of the electromagnetic spectrum.
"Carrier Sense" means that a transmitter uses feedback from a receiver to know if the medium is already in use before trying to send. That is, it tries to find a signal from another station before trying to transmit. If a signal is found, the station waits for that transmission to end before starting its own transmission.
"Multiple Access" means that many stations send and receive on the medium. Transmissions are usually received by all other stations using the medium.
Archaean
The Archaean (or Archean) eon is the geological period after the Hadean and before the Proterozoic. It is one of the four main time periods (eons) of Earth history. The Archaean lasted from 4,000 million years ago (mya) to 2,500 mya. It contains the first sedimentary rocks, and the first fossil life forms, which were cyanobacteria, and acritarchs.
Most of the rocks which survive are volcanic (igneous) and metamorphic in origin. Volcanic activity was everywhere. When the Archaean began, the Earth's heat flow was nearly three times higher than it is today. It was still twice the current level when the Archaean ended, 2,500 mya. This high level of heat flow may have made plate tectonics more vigorous than today. The question of when plate tectonics began is a major research area. The large supercontinent Vaalbara formed in the Archaean. There were oceans already, before the Archaean.
The atmosphere almost entirely lacked free oxygen, and instead, it was mostly methane and CO.
Fossil bacterial mats, called stromatolites, are found throughout the Archaean after about 3,500mya. These were formed by cyanobacteria, which used photosynthesis and gave off oxygen as a by-product. Initially, this oxygen was absorbed by combining with iron ions in solution. Not until much later did oxygen build up in the atmosphere.
Fossil raindrop marks have been found in the later Archaean, 2,700 mya. The rocks were discovered in Ventersdorp in the North West Province of South Africa in the 1980s.
Barcelona Metro line 1
Line 1, shortened to L1 and known as "Hospital de Bellvitge - Fondo", coloured red and often simply called "Línia vermella" ("Red Line"), is the second oldest metro line in Barcelona, after L3. It is operated by Transports Metropolitans de Barcelona (TMB).
Stations or lines shown in italics are under construction.
Hadean
The Hadean is the geological eon before the Archaean. It began at the Earth's formation about 4.6 billion years ago, and ended 4 billion years ago. The name "Hadean" comes from Hades, Greek for "Underworld", due to the conditions on the Earth at the time. The geologist Preston Cloud first used the term in 1972. Meteorite bombardment, volcanism and high temperatures were very widespread on the early Earth.
There are no sedimentary rocks from the Hadean at all. The earliest geological objects on Earth are some zircons, dated to about 4,400 million years ago (mya). Oceans would probably have formed as soon as the temperature allowed. It is thought that constant bombardment kept the Earth in a molten state until about the end of the eon.
Early in Earth history, the Moon was torn out by a massive collision with a proto-planet. The evidence for this giant impact hypothesis is: