Search results
Results from the WOW.Com Content Network
Blastoids (class Blastoidea) are an extinct type of stemmed echinoderm, often referred to as sea buds. [1] They first appear, along with many other echinoderm classes, in the Ordovician period, and reached their greatest diversity in the Mississippian subperiod of the Carboniferous period.
Deep-water anoxia and euxinia would impact deep-water benthic fauna, as expected for the first pulse of extinction. Chemical cycle disturbances would also steepen the chemocline, restricting the habitable zone of planktonic fauna which also go extinct in the first pulse. This scenario is congruent with both organic carbon isotope excursions and ...
About 1,900 species of starfish live on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at 6,000 m (20,000 ft) below the surface. Starfish are marine invertebrates. They typically have a central disc and usually five arms, though some ...
Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction , [ 9 ] often comprising an accumulation of smaller extinction events over ...
Trilobites are an extinct group of ancient marine Arthropods that lived from the early Cambrian period (roughly 541 mya) to the great Permian extinction (252 mya). The name trilobite refers to the three lobes every trilobite body has: the axial lobe, running down the center of the animal, and the pleural lobes, located on either side of the ...
Eight of the extinct bird species were found in Hawaii, including the Po`ouli, which was last seen in 2004. The Po`ouli is the most recently seen species of all 21 animals on the list.
However, pinpointing the extinction of these different land reptile groups is difficult, as the last stage of the Triassic, the Rhaetian, and the first stage of the Jurassic, the Hettangian, each have few records of large land animals; some paleontologists have considered only phytosaurs and procolophonids to have become extinct at the Triassic ...
The seed plants underwent their first major evolutionary radiation in the Famennian era. [103] This seed model is shared by basically all gymnosperms (literally: "naked seeds"), most of which encase their seeds in a woody cone or fleshy aril (the yew, for example), but none of which fully enclose their seeds. The angiosperms ("vessel seeds ...