The life history of Cyclops scutifer Sars (Copepoda: Cyclopoida) in a small lake of the Matamek River System, Quebec

1978 ◽  
Vol 56 (12) ◽  
pp. 2603-2607 ◽  
Author(s):  
J. J. Boers ◽  
J. C. H. Carter
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Calanoid Copepod ◽  
River System ◽  
The Other ◽  
Cyclopoid Copepod ◽  
Small Lake ◽  
History Of ◽  
Cyclops Scutifer ◽  
Copepoda Cyclopoida

A study of the life history of the cyclopoid copepod Cyclops scutifer Sars in a small lake of the Matamek River System, Quebec, indicates a 1-year life cycle with four cohorts produced annually. The primary cohort overwinters as early nauplii and reaches maturity during midsummer when it spawns the primary cohort of the succeeding year. The other cohorts may merge with either each other or the primary cohort and contribute somewhat less to the overall cycle. Slower development of copepodites of the second cohort in 1976 may have been the result of an inadequate number of naupliar prey from the calanoid copepod Diaptomus minutus.

Instar development rates of Diaptomus minutus (Copepoda: Calanoida) in a small lake in Quebec

1978 ◽  
Vol 56 (8) ◽  
pp. 1710-1714 ◽  
Author(s):  
J. J. Boers ◽  
J. C. H. Carter
Keyword(s):  
Life History ◽  
Calanoid Copepod ◽  
River System ◽  
Small Lake ◽  
Development Rates ◽  
History Of

A study of the life history of the calanoid copepod Diaptomus minutus Lilljeborg in C-22, a small lake of the Matamek River System, Quebec, demonstrated that instar duration times of the nauplii and younger copepodites in the major generation were considerably shorter than those reported elsewhere. It is hypothesized that these differences may be attributable to the abundance of nannoplankters characteristic of highly oligotrophic waters.

scholarly journals VIII. Observations on coprozoic flagellates: Together with a suggestion as to the significance of the kinetonucleus in the binucleata

1916 ◽  
Vol 207 (335-347) ◽  
pp. 375-412 ◽  
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Alimentary Canal ◽  
The Other ◽  
Considerable Time ◽  
Parasitic Fauna ◽  
History Of ◽  
Active Condition ◽  
Soil Protozoa ◽  
The Subject

Since publishing, with Mr. Lapage, the first account of the life-cycle of Helkesimastix facicola , I have continued to work alone on the biology and life-history of the flagellates occurring in simple dung-cultures. In the course of this investigation, I have made certain observations which I wish here to record, together with one or two suggestions which I have to offer. The work promises to occupy considerable time before it is completed, and in the case of some of the forms studied I am not yet able to describe the life-cycle in its entirety. Little or no attention has been paid hitherto to the protozoa active in dung, and the study of this fauna is probably not without interest and importance in connection with the subject of the soil-protozoa. To distinguish those protozoa which are carried through the alimentary canal in a passive, encysted condition and become active and go through their life-history in the moist dung, Prof. Minchin has suggested, in the course of his lectures, the useful term coprozoic . The coprozoic fauna of goats and sheep is entirely different from their parasitic fauna, which has for its principal habitat the rumen. Neither the various specialised ciliates (of the fam. Ophryoscolecidæ ) nor the flagellates ( Sphæromonas , Trichomastix and Callimastix ), some of which are invariably present in the rumen, ever occur in an active condition in dung-cultures; and, on the other hand, I have never found any of the coprozoic flagellates active in the rumen-contents, when freshly examined. These facts, readily determined because the sets of forms in the two cases are entirely different, afford important confirmation of the view, now generally accepted, that the Entamæbæ —the truly parasitic forms—are quite distinct from the Amoebæ which develop in fæcal cultures, i. e .,coprozoic species.

scholarly journals The chromosome cycle in Coccidia and Gregarines

1915 ◽  
Vol 89 (610) ◽  
pp. 83-94 ◽  
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Chromosome Numbers ◽  
Life Histories ◽  
The Other ◽  
Chromosome Cycle ◽  
History Of ◽  
Careful Investigation

Despite the large amount of work which has already been devoted to the study of the Coccidia and Gregarines, very little indeed is known definitely about the behaviour of the chromosomes in these Protozoa. Not only has the chromosome cycle been left uninvestigated and undescribed in the majority of these organisms which have hitherto been studied, but the very existence of chromosomes in the nuclear divisions at many stages in the life-history of certain forms has even been denied; and the most contradictory and unsatis­factory accounts have been given of that most important phase in the life-cycle of the chromosomes—the phase of meiosis, or reduction. In order to fill up this gap in our knowledge of the Sporozoa, we have made —during the last few years—a very detailed study of the chromosomes of a coccidian and a gregarine. One of us (C. D.) has investigated the coccidian Aggregate eberthi Labbé, whilst the other (A. P. J.) has studied the gregarine Diplocystis schneideri Kunstler. Careful investigation of these two organisms has shown that the nuclear divisions at all stages in the life-histories are mitotic, and that the chromosome numbers are remarkably constant.

Cycles de développement de Skistodiaptomus oregonensis, Tropocyclops prasinus et Cyclops scutifer dans la zone limnétique du lac Cromwell, Saint-Hippolyte, Québec

1982 ◽  
Vol 60 (2) ◽  
pp. 139-151 ◽  
Author(s):  
Michèle Paquette ◽  
Bernadette Pinel-Alloul
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Water Temperature ◽  
Food Availability ◽  
Development Times ◽  
Decisive Importance ◽  
History Of ◽  
Cyclops Scutifer

A study of the life history of the three principal copepods (Skistodiaptomus oregonensis, Tropocyclops prasinus, Cyclops scutifer) in Lake Cromwell, Québec, demonstrated that these species are multivoltine. Skistodiaptomus oregonensis and T. prasinus have analogous life cycle strategies with two cohorts produced annually and active winter diapause as instar CV and adult; however, their reproductive periods are 2 months apart (May and July). Cyclops scutifer has two summer cohorts and a winter cohort without active diapause. The development times of cohorts are strongly related to water temperature but food availability and water oxygenation could also be of decisive importance for the development of summer cohorts.

Life-history and ultrastructure of a new marine species of Proterospongia (Choanoflagellida)

1983 ◽  
Vol 63 (1) ◽  
pp. 135-160 ◽  
Author(s):  
Barry S. C. Leadbeater
Keyword(s):  
Electron Microscopy ◽  
Life History ◽  
Life Cycle ◽  
Single Cells ◽  
Marine Species ◽  
The Other ◽  
Developmental Problems ◽  
Starting Point ◽  
History Of ◽  
Whole Mounts

The morphology and microanatomy of two different phases in the life history of a single new marine choanoflagellate (Proterospongia choanojuncta sp.nov.) have been documented and described with the aid of light microscopy and from electron microscopy of whole mounts and sections of material in clonal culture. Completion of the life-cycle has been repeatedly achieved in cultures established from single cells, regardless of which phase is used as a starting point. One phase is colonial and motile (the Proterospongia phase) and the other unicellular and sedentary (the Choanoeca phase). Taxonomic, nomenclatural and developmental problems are summarized and discussed.

scholarly journals On Apogamy and the development of Sporangia upon fern prothalli

1898 ◽  
Vol 63 (389-400) ◽  
pp. 56-61
Keyword(s):  
Life History ◽  
Point Of View ◽  
The Other ◽  
Normal Life ◽  
Other Hand ◽  
General Importance ◽  
Two Generations ◽  
History Of ◽  
Alternation Of Generations

The two most important deviations from the normal life-history of ferns, apogamy and apospory, are of interest in themselves, but acquire a more general importance from the possibility that their study may throw light on the nature of alternation of generations in archegoniate plants. They have been considered from this point of view Pringsheim, and by those who, following him, regard the two generations as homologous with one another in the sense that the sporophyte arose by the gradual modification of individuals originally resemblin the sexual plant. Celakovsky and Bower, on the other hand, maintaint the view tha t the sporophyte, as an interpolated stage in the life-history arising by elaboration of the zygote, a few thallophytes.

scholarly journals Effect of NaCl on seed germination in some Centaurium Hill. Species (Gentianaceae)

2007 ◽  
Vol 59 (3) ◽  
pp. 227-231 ◽  
Author(s):  
S. Zivkovic ◽  
M. Devic ◽  
B. Filipovic ◽  
Z. Giba ◽  
D. Grubisic
Keyword(s):  
Life History ◽  
Salt Tolerance ◽  
Seed Germination ◽  
Gibberellic Acid ◽  
White Light ◽  
The Other ◽  
Distilled Water ◽  
Nacl Concentration ◽  
History Of ◽  
Species Specific

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .

The reproduction and larval development of Nereis fucata (Savigny)

1959 ◽  
Vol 38 (1) ◽  
pp. 65-80 ◽  
Author(s):  
J. B. Brown-Gilpin
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Experimental Methods ◽  
Point Of View ◽  
Hermit Crabs ◽  
Special Importance ◽  
Reproductive Patterns ◽  
Complete Life Cycle ◽  
History Of ◽  
The Many

The wide variety of reproductive patterns and behaviour in the many species of Nereidae already studied clearly justifies further research. But the life history of Nereis fucata (Savigny) is not only of interest from the comparative point of view. Its commensal habit (it occurs within shells occupied by hermit crabs) immediately gives it a special importance. This alone warrants a detailed study, particularly as no commensal polychaete has yet been reared through to metamorphosis and settlement on its host (Davenport, 1955; Davenport & Hickok, 1957). The numerous interesting problems which arise, and the experimental methods needed to study them, are, however, beyond the range of a paper on nereid development. It is therefore proposed to confine the present account to the reproduction and development up to the time when the larvae settle on the bottom. The complete life cycle, the mechanism of host-adoption, and related topics, will be reported in later papers.

scholarly journals A STUDY OF THE LIFE HISTORY OF TRICHOBILHARZIA CAMERONI SP. NOV. (FAMILY SCHISTOSOMATIDAE)

1953 ◽  
Vol 31 (4) ◽  
pp. 351-373 ◽  
Author(s):  
Liang-Yu Wu
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Room Temperature ◽  
Migratory Birds ◽  
Local Infection ◽  
Domestic Ducks ◽  
Ottawa River ◽  
Daughter Sporocyst ◽  
Physa Gyrina ◽  
History Of

A cause of swimmer's itch in the lower Ottawa River is Trichobilharzia cameroni sp. nov. Its life cycle has been completed experimentally in laboratory-bred snails and in canaries and ducks, and the various stages are described. The eggs are spindle-shaped. The sporocysts are colorless and tubular. Mother sporocysts become mature in about a week. The younger daughter sporocyst is provided with spines on the anterior end and becomes mature in about three weeks. The development in the snail requires from 28 to 35 days. A few cercariae were found to live for up to 14 days at 50 °C., although their life at 16° to 18 °C. was about four days. Cercariae kept at room temperature for 60 to 72 hr. were found infective. The adults become mature in canaries and pass eggs in about 12 to 14 days. Physa gyrina is the species of snail naturally infected. It was found in one case giving off cercariae for five months after being kept in the laboratory. Domestic ducks were found to become infected until they were at least four months old, with the parasites developing to maturity in due course; no experiments were made with older ducks. Furthermore, miracidia were still recovered from the faeces four months after the duck had been experimentally infected, and it is suggested that migratory birds are the source of the local infection.

The Odd Man Out in a Pioneer Cemetery at Seccombe Lake Park, San Bernardino, California

2020 ◽  
pp. 90-113
Author(s):  
Patricia M. Lambert
Keyword(s):  
Life History ◽  
Native American ◽  
Morphological Traits ◽  
The Other ◽  
European Ancestry ◽  
Latter Day Saints ◽  
Community Members ◽  
San Bernardino ◽  
History Of ◽  
The 19Th Century

In 1989, a pioneer cemetery associated with the 19th-century Latter-Day Saints colony in San Bernardino, California, was discovered during the construction of a baseball field. Among the remains of 12 individuals recovered from the cemetery were those of a young man of about 22 years, whose burial treatment differed notably from the other intact interments at the site. Unlike these coffin burials, Burial 5 was found in a sprawling position, apparently tossed unceremoniously into the grave pit. Dental morphological traits identified the genetic affinities of this man as Native American, perhaps a member of the local Cahuilla or Serrano tribes, whereas the other individuals appeared to be of European ancestry, an interpretation consistent with records kept by community members. A possible identity for this individual came from a journal account describing the shooting of an “Indian” by the local sheriff, who was then brought to the fort, died, and was buried before his fellow tribesmen arrived to determine what had transpired and perhaps to claim his remains. This chapter explores the identity and life history of this young man in the context of the history of the valley and the pioneer community in which he met his death.

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