What's the difference between ordovician and period?

Ordovician


Definition:

  • (a.) Of or pertaining to a division of the Silurian formation, corresponding in general to the Lower Silurian of most authors, exclusive of the Cambrian.
  • (n.) The Ordovician formation.

Example Sentences:

  • (1) 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).
  • (2) His message remains blunt today: “Show me a scientist who claims there is no population problem and I’ll show you an idiot.” Earth’s five previous mass extinctions End-Ordovician, 443 million years ago A severe ice age led to sea level falling by 100m, wiping out 60-70% of all species which were prominently ocean dwellers at the time.
  • (3) – Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous … 'What will survive of us is love', wrote Philip Larkin.
  • (4) It begins with a discussion of the origins of the craniofacial tissues in the dentine and bone of the dermal denticles of the Ordovician jawless vertebrates, followed by a brief discussion of the mechanisms responsible for the evolution of the jaws and the origin of vertebrate dentition.
  • (5) In each of the following, more than half the Earth’s species disappeared: 1 End-Ordovician, 443 million years ago.
  • (6) 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.
  • (7) Dentine, the bone of attachment associated with dentine, the basal bone to which dermal denticles are fused and cartilage of the Ordovician agnathan dermal exoskeleton were all derived from the neural crest and not from mesoderm.
  • (8) Cartilage (unmineralized) can be inferred to have been present in heterostracans and osteostracans, and globular mineralized cartilage was present in Eriptychius, an early Middle Ordovician vertebrate unassigned to any established group, but assumed to be a stem agnathan.
  • (9) The contemporaneous appearance of cellular and acellular bone in heterostracans and osteostracans during the Ordovician provides no clue as to whether one is more primitive than the other.

Period


Definition:

  • (n.) A portion of time as limited and determined by some recurring phenomenon, as by the completion of a revolution of one of the heavenly bodies; a division of time, as a series of years, months, or days, in which something is completed, and ready to recommence and go on in the same order; as, the period of the sun, or the earth, or a comet.
  • (n.) A stated and recurring interval of time; more generally, an interval of time specified or left indefinite; a certain series of years, months, days, or the like; a time; a cycle; an age; an epoch; as, the period of the Roman republic.
  • (n.) One of the great divisions of geological time; as, the Tertiary period; the Glacial period. See the Chart of Geology.
  • (n.) The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion.
  • (n.) A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence.
  • (n.) The punctuation point [.] that marks the end of a complete sentence, or of an abbreviated word.
  • (n.) One of several similar sets of figures or terms usually marked by points or commas placed at regular intervals, as in numeration, in the extraction of roots, and in circulating decimals.
  • (n.) The time of the exacerbation and remission of a disease, or of the paroxysm and intermission.
  • (n.) A complete musical sentence.
  • (v. t.) To put an end to.
  • (v. i.) To come to a period; to conclude. [Obs.] "You may period upon this, that," etc.

Example Sentences:

  • (1) Without medication atypical ventricular tachycardia develops, in the author's opinion, most probably when bradycardia has persisted for a prolonged period.
  • (2) Disease stabilisation was associated with prolonged periods of comparatively high plasma levels of drug, which appeared to be determined primarily by reduced drug clearance.
  • (3) Although the mean values for all hemodynamic variables between the two placebo periods were minimally changed, the differences in individual patients were striking.
  • (4) It was shown in experiments on four dogs by the conditioned method that the period of recovery of conditioned activity after one hour ether anaesthesia tested 7 to 7.5 days.
  • (5) Under blood preservation conditions the difference of the rates of ATP-production and -consumption is the most important factor for a high ATP-level over long periods.
  • (6) No significant change occurred in the bacterial population of our hospital unit during the period of the study (more than 3 years).
  • (7) The secondary leukemia that occurred in these patients could be distinguished from the secondary leukemia that occurs after treatment with alkylating agents by the following: a shorter latency period; a predominance of monocytic or myelomonocytic features; and frequent cytogenetic abnormalities involving 11q23.
  • (8) Sixteen patients in whom schizophrenia was initially diagnosed and who were treated with fluphenazine enanthate or decanoate developed severe depression for a short period after the injection.
  • (9) During the study period four family outbreaks and seven recurrences of infection were observed.
  • (10) After a period on fat-rich diet the patient's physical fitness was increased and the recovery period after the acute load was shorter.
  • (11) During this period he developed autoimmune haemolytic anaemia, a rare complication of myelofibrosis.
  • (12) Pituitary weight, mitotic index and chromosomes were studied in male rats following a single or repeated dose of estradiol-benzoate for a total period of 210 days.
  • (13) Most thyroid hormone actions, however, appear in the perinatal period, and infants with thyroid agenesis appear normal at birth and develop normally with prompt neonatal diagnosis and treatment.
  • (14) Maximal aberration yields were observed for 2,4-diaminotoluene, 2,6-diaminotoluene and cytosine beta-D-arabinofuranoside from 17 to 21 h, eugenol from 15 to 21 h, cadmium sulfate from 15 to 24 h and 2-aminobiphenyl, from 17 to 24 h. For adriamycin at 1 microM, the % aberrant cells remained elevated throughout the period from 9 to 29 h, while small increases at 0.1 microM ADR were found only at 13 and at 25 h. For most chemicals the maximal aberration yield occurred at a different time for each concentration tested.
  • (15) Accuracy of discrimination of letters at various preselected distances was determined each session while Ortho-rater examinations were given periodically throughout training.
  • (16) During electrophysiologic study, the effect of propafenone on the effective refractory period of the accessory pathway was determined, as well as its effect during orthodromic atrioventricular (AV) reentrant tachycardia and atrial fibrillation.
  • (17) Time-series analysis and multiple-regression modeling procedures were used to characterize changes in the overall incidence rate over the study period and to describe the contribution of additional measures to the dynamics of the incidence rates.
  • (18) Throughout the period of rehabilitation, the frequent changes of a patient's condition may require a process of ongoing evaluation and appropriate adjustments in the physical therapy program.
  • (19) Anthropometric and nutritional (serum albumin and transferrin) values were normal in both groups both at the beginning and at the end of the treatment period.
  • (20) Analysis of conjugated discharges ACHs showed that they appeared predominantly periodically (87% of cases).

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