Devonian - Marine biota. Sea levels in the Devonian were generally high. Marine faunas continued to be dominated by bryozoa, diverse and abundant brachiopods and corals. Lily-like crinoids were abundant, and trilobites were still fairly common, but less diverse than in earlier periods. The ostracoderms were joined in the mid-Devonian by the first jawed fishes, the great armored placoderms, as well as the first sharks and ray-finned fish. The first shark, the Cladoselache, appeared in the oceans during the Devonion period. They became abundant and diverse. In the late Devonian the lobe-finned fish ap ...

See also:

Devonian, Devonian - Naming, Devonian - Devonian subdivisions, Devonian - Upper most recent, Devonian - Middle, Devonian - Lower oldest, Devonian - Devonian palaeogeography, Devonian - Devonian fauna, Devonian - Marine biota, Devonian - Reefs, Devonian - Terrestrial biota

Read more here: » Devonian: Encyclopedia II - Devonian - Devonian fauna

Although corals first appeared in the Cambrian period, some 570 million years ago, they are extremely rare as fossils until the Ordovician period, when Rugose and Tabulate corals became widespread. Tabulate corals occur in the limestones and calcareous shales of the Ordovician and Silurian periods, and often form low cushions or branching masses alongside Rugose corals. Their numbers began to decline during the middle of the Silurian period and they finally became extinct at the end of the Permian period. The skeletons of Tabulate corals are composed of a ...

See also:

Coral, Coral - Coral types, Coral - Geological history, Coral - Environmental effects on coral, Coral - Uses

Read more here: » Coral: Encyclopedia II - Coral - Geological history

Subclass Labyrinthodontia - extinct Subclass Lepospondyli - extinct Subclass Lissamphibia   Anura   Caudata   Gymnophiona Amphibians (class Amphibia) are a taxon of animals that include all tetrapods (four-legged vertebrates) that do not have amniotic eggs. Amphibians (from Greek αμφις "both" and βιος "life") generally spend part of their time on land, but they do not have the adaptations to an entirely terrestrial existence ...

Including:

• Amphibian - History of amphibians
• Amphibian - Classification
• Amphibian - Reproduction
• Amphibian - External references

Read more here: » Amphibian: Encyclopedia - Amphibian

Ammonites are an extinct group of marine animals (subclass Ammonoidea) in the phylum Mollusca and class Cephalopoda. Their closest living relative is probably not the modern Nautilus, whom they resemble, but rather the Subclass Coleoidea (octopus, squid, and cuttlefish). Their fossil shells take the form of flat spirals (though there are some rarer helically spiraled and non-spiraled forms, called heteromorphs) and are responsible for the animals' name as they somewhat resemble a tightly coiled ram's horn (the god Ammon was com ...

Including:

• Ammonite - Classification
• Ammonite - Life
• Ammonite - Shell anatomy and diversity
• Ammonite - Basic shell anatomy
• Ammonite - Sexual dimorphism
• Ammonite - Variations in shape
• Ammonite - The aptychus
• Ammonite - Size
• Ammonite - Ammonite distribution
• Ammonite - Trivia
• Ammonite - References and further reading

Read more here: » Ammonite: Encyclopedia - Ammonite

An anoxic event occurs when the Earth's oceans become completely depleted of O2 below the surface levels. Anoxic event - Occurrence. Anoxic events occur only during periods of very warm climate characterised by high levels of CO2, usually above 1800 ppmv, and mean surface temperatures of around 22 ° C (Quaternary levels are 280 ppmv and 13 ° C). Thus, anoxic events have been concentrated in the Paleogene, Cretaceous and Jurassic, when numoerous ones have been documented ...

Including:

• Anoxic event - Occurrence
• Anoxic event - Major anoxic events in the Cretaceous
• Anoxic event - Mechanism
• Anoxic event - Consequences

Read more here: » Anoxic event: Encyclopedia - Anoxic event

Apterygota is a subclass of insects that are small agile insects, distinguised from other insects by their lack of wings now and in their evolutionary history. Their first known occurrence in the fossil record is in the Devonian period, 417-354 million years ago. The younger stages (nymphs) go through little or even no metamorphosis, so they reseble the adult specimens. Their skin is thin, making them translucent. There are no current species at conservation risk. Apterygota - Sources. Including:

• Apterygota - Sources

Read more here: » Apterygota: Encyclopedia - Apterygota

Allegany County is a county located in the U.S. state of New York. As of 2000, the population is 49,927. Its name derives from a Delaware Indian word, applied by settlers of Western New York State to a trail that followed the Allegany (Allegheny) River. Its county seat is Belmont. Allegany County New York - History. When counties were established in New York State in 1683, the present Allegany County was part of Albany County. This was an enormous county, including the northern part of New York State as wel ...

Including:

• Allegany County New York - History
• Allegany County New York - Geography
• Allegany County New York - Demographics
• Allegany County New York - Towns and Villages
• Allegany County New York - Indian reservations
• Allegany County New York - Information about Allegany County
• Allegany County New York - Educational institutions
• Allegany County New York - Adjacent Counties and areas

Read more here: » Allegany County New York: Encyclopedia - Allegany County New York

The Archaeognatha are known as the bristletails, so named because of their three-pronged tails. An alternate name is the Microcoryphia from micro, small and coryphia, head. They are among the least evolutionarily changed insects, appearing in the Devonian period along with the Arachnids. The name Archaeognatha is derived from Greek. Archaeos meaning ancient is combined with gnatha meaning jaw. There are approximately 350 species in the two families. They are distributed worldwide, and unusual in the ...

Including:

• Archaeognatha - Sources

Read more here: » Archaeognatha: Encyclopedia - Archaeognatha

Adam Sedgwick (March 22, 1785 – January 27, 1873) was one of the founders of modern geology. He proposed the Devonian period of the geological timescale and later the Cambrian period. The latter proposal was based on work which he did on Welsh rock strata. Sedgwick was born in Dent, at that time in Yorkshire, the third child of an Anglican vicar. He was educated at Sedbergh School and Trinity College, Cambridge. Adam Sedgwick - Introduction. In 1817 he took holy orders, and in 1818 he became Woodwa ...

Including:

• Adam Sedgwick - Introduction
• Adam Sedgwick - Early work
• Adam Sedgwick - Disagreement with Darwin
• Adam Sedgwick - Flawed opinions
• Adam Sedgwick - External link

Read more here: » Adam Sedgwick: Encyclopedia - Adam Sedgwick

The mammals are the class of vertebrate animals characterized by the presence of mammary glands, which in females produce milk for the nourishment of young; the presence of hair or fur; and which have endothermic or "warm-blooded" bodies. The brain regulates endothermic and circulatory systems, including a four-chambered heart. Mammals encompass some 5500 species, distributed in about 1200 genera, 152 families and up to 46 orders, though this varies depending on the classification scheme adopted. Phylogenetically, MammaliaIncluding:

• Mammal - Characteristics
• Mammal - Origins
• Mammal - In the Mesozoic
• Mammal - In the Paleocene
• Mammal - Classification
• Mammal - Standardized textbook classification
• Mammal - McKenna/Bell classification
• Mammal - Molecular classification of placentals
• Mammal - Classification system used in related articles

Read more here: » Mammal: Encyclopedia - Mammal

Insects are invertebrate animals of the Class Insecta, the largest and (on land) most widely distributed taxon within the Phylum Arthropoda. Insects comprise the most diverse group of animals on the earth, with over 800,000 species described—more than all other animal groups combined: "Indeed, in no one of her works has Nature more fully displayed her exhaustless ingenuity," Pliny exclaimed. Insects may be found in nearly all environments on the planet, although only a small number of species have adapted to life in the ocean ...

Including:

• Insect - Relationship to other arthropods
• Insect - Morphology and development
• Insect - Behavior
• Insect - Roles in the environment and human society
• Insect - Fossils and evolution
• Insect - Quotes

Read more here: » Insect: Encyclopedia - Insect

Climatiiformes Ischnacanthiformes Acanthodiformes Acanthodii (sometimes called spiny sharks) is a class of extinct fishes, having features of both bony fish ( Osteichthyes) and cartilaginous fish (Chondrichthyes). They appeared in the early Silurian (430 mya) and lasted until the late Permian (250 mya). The earliest ancanthodians were marine, but during the Devonian, freshwater species became predominant. They are distinguished in two respects: they were the first known jawed vertebrates, and they had stout spines supporting their fins, fixed in p ...

Read more here: » Acanthodii: Encyclopedia - Acanthodii

Acritarchs are small organic structures found as fossils. In general, any small, non-acid soluble (i.e. non carbonate, non-silicate) organic structure that can not otherwise be accounted for is an acritarch. Most acritarchs are surely remains of single celled lifeforms. They are found in sedimentary rocks from the present back into the Precambrian. They are easily isolated from limestones with hydrochloric acid, and can also be isolated from silica rich rocks using hydrofluoric acid. They are excellent candidates for index fossils to ...

Read more here: » Acritarch: Encyclopedia - Acritarch

Archaeopteris is an extinct genus of tree-like ferns that many scientists believe to be the first tree. A useful index fossil, this tree is found in strata dating from the Upper Devonian to Lower Carboniferous. Fossils are found in Europe, North America, and Morocco in North Africa. Some specimines have also been reported from Australia. Many scientists consider Archaeopteris to be the earliest known modern tree, with buds, reinforced branch joints, and branched trunks similar to today's timber. The genus Archa ...

Including:

• Archaeopteris - Anatomy
• Archaeopteris - Other modern adaptations
• Archaeopteris - Habitat
• Archaeopteris - Relationship to conifers
• Archaeopteris - Discovery and classification

Read more here: » Archaeopteris: Encyclopedia - Archaeopteris

Conservation status: Endangered Latimeria chalumnae Latimeria menadoensis Coelacanth (meaning "hollow spine" in Greek; IPA: /ˈsiːləˌkænθ/) is a species of fish and represents the oldest lineage of living fish known to date. The coelacanth was believed to have been extinct since the end of the Cretaceous period — until a live specimen turned up off the east coast of South Africa off the Chalumna River in 1938. Since the ...

Including:

• Coelacanth - Biological characteristics
• Coelacanth - Fossil Record
• Coelacanth - Morphology of the coelacanth skeleton
• Coelacanth - Discovery
• Coelacanth - First find in South Africa
• Coelacanth - Comoros
• Coelacanth - Second species in Indonesia
• Coelacanth - St. Lucia Marine Protected Area in South Africa
• Coelacanth - Taxonomic notes

Read more here: » Coelacanth: Encyclopedia - Coelacanth

To help compare orders of magnitude of different times this page lists times between 1016 seconds (320 million years) and 1017 seconds (3200 million years). See also times of other orders of magnitude. Shorter times 340 million years -- time since beginning of Carboniferous Period 340 million years -- time since end of Devonian Period 400 million years -- time since beginning of Devonian Period 400 million years -- time since end of Silurian Period 420 mil ...

Read more here: » 1 E16 s: Encyclopedia - 1 E16 s

Baltica is the craton beneath northwestern Eurasia. Occasionally, Baltica was an independent continent. This is a brief history of Baltica: Baltica - Partial history of Baltica in chronological order. ~2 billion years ago, Baltica formed. ~1.8 billion years ago, Baltica was part of the major supercontinent Columbia. ~1.5 billion years ago, Baltica along with Arctica and Eastern Antarctica were part of the minor supercontinent Nena. ~1.1 billion years ago, Baltica was ...

Including:

• Baltica - Partial history of Baltica in chronological order

Read more here: » Baltica: Encyclopedia - Baltica

Yosemite National Park (pronounced "Yo-SEM-it-tee", IPA [joʊˈsɛməti]) is a national park largely in Mariposa County, and Tuolumne County, California, United States. The park covers an area of 1,189 mi² (3,081 km²) and stretches across the western slopes of the Sierra Nevada mountain range. Over 3 million people visit Yosemite each year, with most only seeing Yosemite Valley. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its spectacular g ...

Including:

• Yosemite National Park - Geography
• Yosemite National Park - Rocks and erosion
• Yosemite National Park - Popular features
• Yosemite National Park - Water and ice
• Yosemite National Park - Climate
• Yosemite National Park - History
• Yosemite National Park - The Ahwahnechee and the Mariposa Wars
• Yosemite National Park - Early tourists
• Yosemite National Park - The Yosemite Grant
• Yosemite National Park - Increased protection efforts
• Yosemite National Park - Later history
• Yosemite National Park - Geology
• Yosemite National Park - Tectonic and volcanic activity
• Yosemite National Park - Uplift and erosion
• Yosemite National Park - Sculpting by glaciers
• Yosemite National Park - Biology
• Yosemite National Park - Habitats
• Yosemite National Park - Management issues
• Yosemite National Park - Activities
• Yosemite National Park - Hiking
• Yosemite National Park - Climbing
• Yosemite National Park - Summer activities
• Yosemite National Park - Winter activities

Read more here: » Yosemite National Park: Encyclopedia - Yosemite National Park

The Carboniferous is a major division of the geologic timescale that extends from the end of the Devonian period, about 359.2 Ma (million years ago), to the beginning of the Permian period, about 299.0 Ma (ICS 2004). As with most older geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by 5–10 million years. The Carboniferous is named for the extensive coal beds of that age found in Great Britain and Western Europe. The first third of the Carboniferous is cal ...

Including:

• Carboniferous - Subdivisions
• Carboniferous - Gzhelian most recent
• Carboniferous - Kasimovian
• Carboniferous - Moscovian
• Carboniferous - Bashkirian/Morrowan
• Carboniferous - Serpukhovian
• Carboniferous - Visean
• Carboniferous - Tournaisian oldest
• Carboniferous - Paleogeography
• Carboniferous - Rocks and coal
• Carboniferous - Life

Read more here: » Carboniferous: Encyclopedia - Carboniferous

Chert is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils. It varies greatly in color from white to black, but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements present in the rock, and both red and green are most often related to traces of iron (in its oxidized and reduced forms respectively). Jasper is basically chert which ...

Including:

• Chert - Chert and Precambrian fossils
• Chert - Chert and flint: archaeological and historical uses

Read more here: » Chert: Encyclopedia - Chert