Portal:Cambrian
The Cambrian Period marked a profound change in life on Earth; prior to the Cambrian, living organisms on the whole were small, unicellular and simple. Complex, multicellular organisms gradually became more common in the millions of years immediately preceding the Cambrian, but it was not until this period that mineralized – hence readily fossilized – organisms became common. The rapid diversification of lifeforms in the Cambrian, known as the Cambrian explosion, produced the first representatives of many modern phyla, representing the evolutionary stems of modern groups of species, such as the arthropods. While diverse life forms prospered in the oceans, the land was comparatively barren – with nothing more complex than a microbial soil crust and a few forms that apparently emerged to browse on the microbial materials. Most of the continents were probably dry and rocky due to a lack of vegetation. Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia. The seas were relatively warm, and polar ice was absent for much of the period. Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Opabinia is an extinct stem-arthropod genus found in Cambrian fossil deposits. The only known species, O. regalis, is known from the Middle Cambrian Burgess Shale Lagerstätte of British Columbia, Canada. Fewer than twenty good specimens have been described. Opabinia was a soft-bodied animal of modest size, and its segmented body had lobes along the sides and a fan-shaped tail. The head shows unusual features: five eyes, a mouth under the head and facing backwards, and a proboscis that probably passed food to the mouth. Opabinia probably lived on the seafloor, using the proboscis to seek out small, soft food.When the first thorough examination of Opabinia in 1975 revealed its unusual features, it was thought to be unrelated to any known phylum, although possibly related to a hypothetical ancestor of arthropods and of annelid worms. However other finds, most notably Anomalocaris, suggested that it belonged to a group of animals that were closely related to the ancestors of arthropods and of which the living animals onychophorans and tardigrades may also be members.(see more...) Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found. Paleontology or palaeontology (/ˌpeɪlɪɒnˈtɒlədʒi/, /ˌpeɪlɪənˈtɒlədʒi/ or /ˌpælɪɒnˈtɒlədʒi/, /ˌpælɪənˈtɒlədʒi/) is the scientific study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments (their paleoecology). As a "historical science" it attempts to explain causes rather than conduct experiments to observe effects. Paleontological observations have been documented as far back as the 5th century BC. The science became established in the 18th century as a result of Georges Cuvier's work on comparative anatomy, and developed rapidly in the 19th century. The term itself originates from Greek: παλαιός (palaios) meaning "old, ancient," ὄν, ὀντ- (on, ont-), meaning "being, creature" and λόγος (logos), meaning "speech, thought, study".Paleontology lies on the border between biology and geology. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, about 3,800 million years ago. As knowledge has increased, paleontology has developed specialized sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates. Body fossils and trace fossils are the principal types of evidence about ancient life, and geochemical evidence has helped to decipher the evolution of life before there were organisms large enough to leave fossils. (see more...) Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found.
Photo credit: User:DanielCD Lua error in package.lua at line 80: module 'Module:Box-header/colours' not found.
Template:/box-header Epochs - Terreneuvian - Cambrian Series 2 - Cambrian Series 3 - Furongian Geography - Pannotia - Baltica - Gondwanaland - Laurentia - Siberia Fossil sites - Walcott Quarry Researchers - Stephen Jay Gould - Simon Conway Morris - Charles Doolittle Walcott Template:/box-header Featured Cambrian articles - None
Current Cambrian FACs - none currently
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