(n.) A fossil cephalopod shell related to the nautilus. There are many genera and species, and all are extinct, the typical forms having existed only in the Mesozoic age, when they were exceedingly numerous. They differ from the nautili in having the margins of the septa very much lobed or plaited, and the siphuncle dorsal. Also called serpent stone, snake stone, and cornu Ammonis.
Example Sentences:
(1) Start your exploring at Bearreraig Bay, where, if you are lucky, you may find belemnites, ammonites and bivalves.
(2) An ambitious project to showcase the prehistory of the south coast of England, famous for its marine fossils from ammonites to giant sea reptiles, has attracted support from David Attenborough and Eden Project founder Tim Smit.
(3) Everest is published by Ammonite Press on 22 May, priced £40.
(4) Cretaceous-Tertiary, 65 million years ago An giant asteroid impact on Mexico, just after large volcanic eruptions in what is now India, saw the end of the dinosaurs and ammonites.
Extinct
Definition:
(a.) Extinguished; put out; quenched; as, a fire, a light, or a lamp, is extinct; an extinct volcano.
(a.) Without a survivor; without force; dead; as, a family becomes extinct; an extinct feud or law.
(v. t.) To cause to be extinct.
Example Sentences:
(1) The stages of mourning involve cognitive learning of the reality of the loss; behaviours associated with mourning, such as searching, embody unlearning by extinction; finally, physiological concomitants of grief may influence unlearning by direct effects on neurotransmitters or neurohormones, such as cortisol, ACTH, or norepinephrine.
(2) The effect upon ethanol responding was found not to resemble a pattern of extinction, but rather was best described as a general overall reduction in responding.
(3) In a recent study, Orr and Lanzetta (1984) showed that the excitatory properties of fear facial expressions previously described (Lanzetta & Orr, 1981; Orr & Lanzetta, 1980) do not depend on associative mechanisms; even in the absence of reinforcement, fear faces intensify the emotional reaction to a previously conditioned stimulus and disrupt extinction of an acquired fear response.
(4) We conclude that the procedure used in this study is a non-intrusive intervention that is an extension of the current literature pertaining to sensory extinction.
(5) After 40 programmed minutes of acquisition and 12 min of maintenance, without notice, both schedules changed to extinction for 28 min.
(6) This differential absorbance is linear with increasing concentrations of Na2MoO4 and was used to calculate the molar extinction coefficient of molybdochelin at 425 nm (epsilon similar to 6,200).
(7) However, during massed testing, all subjects trained with response contingent CS termination showed an overall extinction influence, which was most pronounced in the medial subgroup, although the laterals showed frequency control as well.
(8) When reinforcement for competing behavior was withdrawn, however, rats resumed their original behavior and there were no overall savings in total responses to extinction.
(9) The relative amount of the crystals was measured in both amoeba strains on the basis of the integral extinction value.
(10) Chronic extinction of chain closed conditioned reflex in intact rabbits took five to six days.
(11) The amounts of phosphatidylcholine and sphingomyelin could be determined by high-performance liquid chromatography and ultraviolet absorption if the apparent extinction coefficient of the material analyzed was established.
(12) In a number of neurones the extinction of reflexes either does not change the reaction to acetylcholine, or enhances it.
(13) In Experiment 3, following an unsignaled reinforcement delay, groups receiving either no event or signaled food in the context responded faster in extinction than groups receiving no context exposure or unsignaled food.
(14) The optical extinction decreases as the red cell agglutinates grow, giving a parametric estimate of the haemagglutination rate.
(15) By calculating for DNA standard solutions the value of the ratio between the extinction at 665 nm after 15 min to the extinction of 600 nm after 2 min of the orcinol reaction it is possible to increase specifiaty of the orcinol method for determination of the RNA content.
(16) To lose the Sundarbans would be to move a step closer to the extinction of these majestic animals," said ZSL tiger expert Sarah Christie.
(17) Values obtained for thebuoyant density, isoelectric point, and extinction coefficient differed minimally; major differences were observed in the molecular weight and the characterisitc width of cylinders formed by in vitro-assembled T-layer of the wild-type and variant.
(18) The CS+ preference persisted for several weeks during extinction tests when both the CS+ and CS- were paired with IG water or with no infusions.
(19) The extinction coefficient at 550 nm for the oxidized enzyme is about 5300 (M subunit)-1 X cm-1.
(20) On this planet, extinction is the norm – of the 4 billion species ever thought to have evolved, 99% have become extinct.