(from the Greek palaios
(παλαιός), "old" and zoe
(ζωή), "life", meaning "ancient life") is the earliest of three geologic eras
of the Phanerozoic Eon
, spanning from roughly 541 to 252.17 million years ago
(ICS, 2004). It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods
(from oldest to least old): the Cambrian
, and Permian
. The Paleozoic comes after the Neoproterozoic Era
of the Proterozoic Eon
, and is followed by the Mesozoic Era
The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Fish, arthropods, amphibians and reptiles all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms. Great forests of primitive plants covered the continents, many of which formed the coalbeds of Europe and eastern North America. Towards the end of the era, large, sophisticated reptiles were dominant and the first modern plants (conifers) appeared.
The Paleozoic Era ended with the largest mass extinction in Earth's history, the Permian–Triassic extinction event. The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic to recover.
Selected article on the Paleozoic world and its legacies
are a class
within the arthropod
phylum that have a chitinous exoskeleton
, a three-part body (head
), three pairs of jointed legs
, compound eyes
and one pair of antennae
. They are among the most diverse groups of animals
on the planet, including more than a million described species
and representing more than half of all known living organisms. Insects may be found in nearly all environments
, although only a small number of species reside in the oceans.
The life cycles of insects vary but most insects hatch from eggs. Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts. The immature stages can differ from the adults in structure, habit and habitat. Insects that undergoincomplete metamorphosis lack a pupal stage and adults develop through a series of nymphal stages. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm (22–28 in). The most diverse insect groups appear to have coevolved with flowering plants.
Adult insects typically move about by walking, flying, or sometimes swimming. Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their lives under water, with larval adaptations that include gills, and some adult insects are aquatic and have adaptations for swimming. Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies. (see more...)
Selected article on the Paleozoic in human science, culture and economics
The geologic map of Georgia
(a state within the United States) is a special-purpose map
made to show geological
units or geologic strata
are shown by colors or symbols to indicate where they are exposed at the surface. Structural features such as faults
and shear zones
are also shown. Since the first national geological map, in 1809, there have been numerous maps which included the geology of Georgia. The first Georgia specific geologic map was created in 1825. The most recent state-produced geologic map of Georgia, by the Georgia Department of Natural Resources
is 1:500,000 scale, and was created in 1976 by the department's Georgia Geological Survey. It was generated from a base map produced by the United States Geological Survey
. The state geologist and Director of the Geological Survey of Georgia was Sam M. Pickering, Jr. Since 1976, several geological maps of Georgia, featuring the state's five distinct geologic regions, have been produced by the federal government. (see more...
Current Paleozoic FACs - none currently