(a.) Of or pertaining to the lowest subdivision of the rocks of the Silurian or Molluscan age; -- sometimes described as inferior to the Silurian. It is named from its development in Cambria or Wales. See the Diagram under Geology.
(n.) A native of Cambria or Wales.
(n.) The Cambrian formation.
Example Sentences:
(1) He and colleagues in Germany and the US studied a database of fossil organisms that lived on the sea floor from the Cambrian period, about 500m years ago.
(2) Furthermore, the identification of vertebrate hard tissues in the oral elements of conodonts extends the earliest occurrence of vertebrate hard tissues back by around 40 million years, from the Middle Ordovician (475 million years ago) to the Late Cambrian (515 million years ago).
(3) The Cambrian period, which began more than half a billion years ago, marks the moment when major groups of animals first appeared as fossils in rock strata.
(4) In the past decade the picture has changed dramatically, and now includes invertebrates from the Cambrian formations of half a billion years ago, many species of birds, rats and mice, antelopes, cats, dogs, whales, and primates.
(5) – Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous … 'What will survive of us is love', wrote Philip Larkin.
(6) The present results support the hypothesis that fever was selected as a way of defending against infection only after the period of the emergence of the molluscus, i.e., the early Cambrian period.
(7) Power cables have stopped services between Aberystwyth and Machynlleth, where the train lines had already taken a battering in recent weeks and parts of the Cambrian line had already been declared closed for some months to come.
(8) Paleontological data indicate that the earliest recognizable vertebrate remains, bone fragments of Upper Cambrian and Lower Ordovician heterostracan fishes, were deposited in a marine situation.
(9) This could explain the sudden presence in the fossil record of the early Cambrian of advanced and diversified metazoans, the earlier forms of which were essentially unpreservable.
(10) Therefore, molluscan hemocyanins already existed before the individual molluscan classes diverged in the early Cambrian.
(11) Dentine is present in the stratigraphically oldest (Cambrian) assumed vertebrate fossils, at present some only included as Problematica, and is cladistically primitive, relative to bone.
(12) In contrast, chemical versatility has generally decreased within groups from the pre-Cambrian to the Phanerozoic, partly as the result of apparent changes in the chemical environment and partly as the consequence of selection for efficiency and greater metabolic ease of handling of certain materials.
Paleozoic
Definition:
(a.) Of or pertaining to, or designating, the older division of geological time during which life is known to have existed, including the Silurian, Devonian, and Carboniferous ages, and also to the life or rocks of those ages. See Chart of Geology.
Example Sentences:
(1) The geographic location of leptospirosis presents a pattern which closely parallels the distribution of Paleozoic bedrock.
(2) In general, the small subunit nuclear sequences appear to be best for elucidating Precambrian divergences, the large subunit nuclear sequences for Paleozoic and Mesozoic divergences, and the organellar sequences of both subunits for Cenozoic divergences.
(3) Recent work on Silurian, Devonian and Carboniferous terrestrial assemblages has provided plausible evidence for all major groups of extant fungi in the Paleozoic.
(4) Of the suborders present in the Paleozoic, seven are morphologically relatively simple, slowly evolving, and continued into Mesozoic and Cenozoic times to become the ancestoral lineages from which evolved several additional post-Paleozoic suborders.
(5) Key events in fungal macroevolution thus probably took place in the early Paleozoic or the late Precambrian, and the likelihood of finding definitive fossil evidence for them is small.
(6) The approximately 300 million years that make up Paleozoic time saw the evolution of eight of the fifteen recognized suborders of Foraminifera.
(7) The preliminary implication of these observations is that the mechanism of physiological color change involving MCH and its melanophore receptors evolved near the end of the Paleozoic or during the early Mesozoic, just before or early in the evolution of neopterygian (holostean and teleostean) fishes.
(8) Their early representatives may have given rise to three and eventually four post-Paleozoic suborders.
(9) The widespread late Paleozoic condition of seasonal drought favored progressive developments which, with the attainment of a reptilian stage, had the happy accidental result of the vertebrate conquest of the land, a conquest aided by the emergence of the insects as a basic food supply.
(10) A number of suborders in the Paleozoic have similar, supposedly independent, early evolutionary patterns with the following series of morphological steps: (1) single chambers with or without apertures depending on the amount of wall cement; (2) groups of chambers that appear to be buds or aggregations of individuals rather than true chambers; (3) a proloculus followed by a tubular second chamber that is first erect and gradually evolves into enrolled free-living individuals; (4) development of constrictions in the tubular chamber; and finally (5) evolution of true chambers.
(11) Fusulinines became extinct at the end of the Paleozoic.
(12) In Ontario, bedrock composed of limestone and dolomite formed in the Paleozoic era appears to be a reliable ecological marker for Leptospira pomona infection.
(13) In contrast, an eighth Paleozoic suborder, the Fusulinina, was an abundant, ecologically dominant group that evolved from simple to highly specialized forms and had a history of rapid evolution with diverse lineages.
(14) Antibodies to L. hardjo and L. sejroe occur in many bovine sera from a predominantly Precambrian area where Paleozoic outliers are numerous.
(15) A marked increase in atmospheric oxygen level near the beginning of the Paleozoic would eliminate oxygen-collagen priorities simultaneously and on a world-wide basis in all metazoan stocks providing evolutionary pressure for enlarged musculatures and associated "hard parts."