The life history of Halosaccion ramentaceum

1981 ◽  
Vol 59 (4) ◽  
pp. 433-436 ◽  
Author(s):  
John P. van der Meer
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
Sexual Maturity ◽  
Mutant Phenotype ◽  
Sexual Cycle ◽  
Palmaria Palmata ◽  
Male And Female ◽  
Haploid Male ◽  
History Of ◽  
Mendelian Transmission

The complete life history of Halosaccion ramentaceum has been determined. It is very similar to that of Palmaria palmata, consisting of haploid male and female gametophytes alternating with a diploid tetrasporophyte. As for P. palmata, there is no carposporophyte. Male and female gametophytes attain sexual maturity almost a generation apart. Whereas male plants require approximately 1 year's growth before producing spermatia, female gametophytes are microscopic and reach sexual maturity only a few days after tetraspore germination. The diploid tetrasporophyte initiates its development on the female, but almost immediately forms an independent holdfast on the substratum beside the female. The first diploid fronds arise from that holdfast after it is well established.The existence of a complete sexual cycle was proven by demonstrating: fertilization of trichogynes by spermatia; meiosis in tetrasporangia, with a chromosome number of n = ~24 in gametophytes and 2n = ~48 in tetrasporophytes; and by documenting the Mendelian transmission of a mutant phenotype from the male parent to the F1 gametophytes.

On the Correlation of the Life-history of the Acephaline Gregarine, Gonospora, with the Sexual Cycle of its Host

Parasitology ◽  
1930 ◽  
Vol 22 (4) ◽  
pp. 505-509 ◽  
Author(s):  
C. C. Hentschel
Keyword(s):  
Life History ◽  
Sexual Maturity ◽  
Sexual Cycle ◽  
History Of

1. In general there is a correlation between the life-history of Gonospora arenicolae and the sexual cycle of its host, Arenicola ecaudata, similar to that between G. varia and Audouinia tentaculata.2. In the species under consideration the correlation is not so definite and the life-history of a generation of parasites does not necessarily coincide with a sexual cycle of the host. This is complicated by the double annual spawning of the host.3. The formation of sporocysts is simultaneous with the sexual maturity of the worm.4. It is suggested that, as in Audouinia, a secretion produced by the gonads stimulates the development of the gregarine.5. The ejection of the sporocysts with the gametes was observed.6. It is suggested that phagocytosis may be the cause of the rupture of the gametocysts in this species.

A contribution towards elucidating the life history of Palmaria palmate (=Rhodymenia palmata)

1976 ◽  
Vol 54 (24) ◽  
pp. 2903-2906 ◽  
Author(s):  
J. P. van der Meer
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
Atlantic Coast ◽  
Palmaria Palmata ◽  
Haploid Chromosome Number ◽  
History Of

Palmaria palmata from a region of the Atlantic coast of Canada has been examined cytologically. Plants bearing tetrasporangia were found to be diploid with meiosis occurring in the tetrasporangia. Spermatangial plants and sporelings growing from tetraspores were haploid. The haploid chromosome number appears to be 22–23.

The life history of Palmaria palmata in culture. A new type for the Rhodophyta

1980 ◽  
Vol 58 (11) ◽  
pp. 1250-1256 ◽  
Author(s):  
John P. van derMeer ◽  
Edna R. Todd
Keyword(s):  
Life History ◽  
Vegetative Growth ◽  
Palmaria Palmata ◽  
Recessive Mutation ◽  
Male And Female ◽  
Carpogonial Branch ◽  
History Of ◽  
New Type ◽  
Sexually Mature ◽  
Older Males

The life history of Palmaria palmata has been completed in culture. Tetraspores from diploid plants gave rise to male and female haploid plants which differed morphologically. Female plants were extremely small and became sexually mature only days after tetraspore release. Trichogynes were observed on plants only 4 days old, and remained conspicuous for several weeks. As the females aged, trichogynes declined in number and they could not be detected on plants 5 months old. In contrast, male plants required several (9–12) months of vegetative growth before they formed spermatia. As a consequence, females had to be fertilized by older males from preceding gametangial generations.The diploid tetrasporangial plants developed directly on fertilized females. As they enlarged, they completely overgrew the small females and formed their own holdfast attachments to the substrate. A recessive mutation resulting in green frond colour was used in crosses designed to yield red diploid tissue on green females after fertilization, thereby greatly facilitating observations on the development of the tetrasporangial phase.Preliminary observations indicate that the carpogonium is a single cell. There appears to be no carpogonial branch or auxilliary cell. The tetrasporangial phase develops from the zygote by simple mitotic divisions, suggesting that the life history is best interpreted as lacking a carposporophyte.

Age, growth, and reproduction in Hector's dolphins

1991 ◽  
Vol 69 (6) ◽  
pp. 1689-1700 ◽  
Author(s):  
Elisabeth Slooten
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Maturity ◽  
Fishing Gear ◽  
Male And Female ◽  
Pulp Cavity ◽  
Traditional Procedure ◽  
History Of ◽  
Growth And Reproduction ◽  
Beach Cast

Data are provided on the reproductive biology and life history of Hector's dolphin, Cephalorhynchus hectori, a species found only in New Zealand waters. Samples were taken from 60 dolphins found beach-cast or killed incidentally in fishing gear. Male and female reproductive tracts were examined macroscopically and histologically, and tooth sections provided an age estimate for each individual. The traditional procedure for preparing dolphin teeth was simplified by using a faster stain and more readily available embedding and sectioning equipment. An important advantage of this method is that it facilitates the cutting of thinner sections, increasing the chances of obtaining a section through the centre of the pulp cavity. Sectioning revealed an open pulp cavity in all the teeth examined. The maximum observed age was 19 years for females and 20 years for males. Females reach a larger body size than males, and are apparently larger than males at any given age. Males appear to reach sexual maturity between 6 and 9 years of age, whereas females give birth to their first calf at 7–9 years of age. Mature males have extremely large testes relative to their body size. The largest male found in this study weighed 41.5 kg, with testes (including epididymides) totalling 1.21 kg.

Life history of Mysis stenolepis Smith (Crustacea, Mysidacea)

1975 ◽  
Vol 53 (7) ◽  
pp. 942-952 ◽  
Author(s):  
T. Amaratunga ◽  
S. Corey
Keyword(s):  
Young Adults ◽  
Life History ◽  
New Brunswick ◽  
Shallow Water ◽  
Field Study ◽  
Sexual Maturity ◽  
Developmental Stages ◽  
Shallow Waters ◽  
Passamaquoddy Bay ◽  
History Of

A 17-month field study showed that Mysis stenolepis in Passamaquoddy Bay, New Brunswick lives for about 1 year. Young are released in shallow water early in spring and grow rapidly during the summer. In the fall, young adults migrate to deeper water where they reach sexual maturity. Transfer of sperm lakes place during winter in deeper regions of the Bay. soon after which the males die. Females survive and in spring migrate to shallow waters to release young after which they die. Females breed once and carry an average of 157 young per brood. Developmental stages of the postmarsupial young are described and discussed.

LIFE HISTORY STUDIES OF THE TOBACCO FLEA BEETLE, EPITRIX HIRTIPENNIS (MELSHEIMER) (COLEOPTERA: CHRYSOMELIDAE)

1987 ◽  
Vol 22 (3) ◽  
pp. 237-244 ◽  
Author(s):  
W. Davis Martin ◽  
G. A. Herzog
Keyword(s):  
Life History ◽  
Larval Stage ◽  
Flea Beetle ◽  
Pupal Stage ◽  
Adult Emergence ◽  
Adult Longevity ◽  
Male And Female ◽  
Controlled Conditions ◽  
History Of ◽  
The Mean

The life history of the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) (= Epitrix parvula Fab.) was studied under the controlled conditions of 27 ± 2.8°C, 80 ± 6% and a 14L:10D photophase. Eggs matured in ca. 4 days, the larval stage, including 3 instars, developed in 13 days, prepupal development took 3 days and the pupal stage lasted approximately 5 days. There was a 24 day interval between oviposition and adult emergence. Females laid 3.1 eggs/day with a 13 day period between adult emergence and first oviposition. The mean number of total eggs/female was 138.6 ± 14.7. Female oviposition continued until a few days before death and adult longevity was approximately 70 days. A visual means of distinguishing between male and female beetles was also developed.

STUDIES ON CESTODES OF THE GENUS TRIAENOPHORUS FROM FISH OF LESSER SLAVE LAKE, ALBERTA: V. DESCRIPTION AND LIFE HISTORY OF TRIAENOPHORUS STIZOSTEDIONIS N.SP.

1945 ◽  
Vol 23d (5) ◽  
pp. 117-127 ◽  
Author(s):  
Richard B. Miller
Keyword(s):  
Life History ◽  
Male Genitalia ◽  
Sexual Maturity ◽  
Morphological Characters ◽  
Parietal Peritoneum ◽  
Stizostedion Vitreum ◽  
Pike Perch ◽  
History Of

Triaenophorus stizostedionis is a pseudophyllidean cestode that occurs as an adult in the intestine of the pike-perch, Stizostedion vitreum. It differs from T. crassus and T. nodulosus in several morphological characters but particularly in the shape of the scolex hooks and the size and disposition of the male genitalia. Sexual maturity is attained in the spring; spawning and death take place during the first two weeks of June. The eggs average 56 μ long by 40 μ wide. The coracidia average 73 by 71 μ. The procercoid develops in the copepod, Cyclops bicuspidatus, in from 10 days to two weeks. When fully grown it reaches 220 μ. The plerocercoids occur encysted on the visceral and parietal peritoneum of the trout-perch, Percopsis omiscomaycus. The life history is completed when an infested trout-perch is swallowed by a pike-perch.

Chromosome cycle in the gregarine Stylocephalus mesomorphi Dev.

Parasitology ◽  
1966 ◽  
Vol 56 (2) ◽  
pp. 199-208
Author(s):  
R. N. Desai
Keyword(s):  
Life History ◽  
Chromosome Number ◽  
The Other ◽  
Medium Size ◽  
Mitotic Chromosomes ◽  
Zygote Nucleus ◽  
Entire Life ◽  
Science College ◽  
History Of ◽  
Zoology Department

The gregarine Stylocephalus mesomorphi has a diploid chromosome number of 8. The diploid stage is represented only by the zygote nucleus before the metagamic divisions start. The other stages in the entire life history of this gregarine are haploid.The mitotic chromosomes are four in number, one being the longest, two of medium size and the fourth the smallest.I am grateful to Professor J. C. Uttangi, Head of the Zoology Department, Karnatak Science College, Dharwar, for the encouragement he gave me throughout this work. I am also greatly indebted to my colleague Dr M. J. Devadhar, for having given me many valuable suggestions.

scholarly journals Life history of Tendaguru sauropods as inferred from long bone histology

Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 103-112 ◽  
Author(s):  
P. M. Sander
Keyword(s):  
Life History ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Sexual Maturity ◽  
Upper Jurassic ◽  
Bone Histology ◽  
Long Bone ◽  
Large Mammals ◽  
Growth Series ◽  
History Of

Abstract. Sauropod dinosaurs present exceptional challenges in understanding their biology because of their exceptional body size. One of these, life history, can be inferred from the histology of their bones. For this purpose, the diverse sauropod assemblage of the Upper Jurassic Tendaguru beds was sampled with a new coring method which provided unprecented access to and insights into sauropod bone histology. Growth series of humeri and femora as well as long growth records from single bones suggest that all four sauropod taxa are characterized by continued growth after sexual maturity but that growth was determinate. Fibrolamellär bone is dominant in the samples, indicating that the bones of the Tendaguru sauropods grew at rates comparable to those of modern large mammals. The growth pattern of these sauropods thus combines typically reptilian traits with typically mammalian traits. In the details of their bone histology, the Tendaguru sauropod taxa show considerable variation which reflects life history. In addition, Barosaurus exhibits probable sexual dimorphism in bone histology. Das Verständnis der Biologie der sauropoden Dinosaurier wird durch ihre enorme Körpergröße außerordentlich erschwert. Allerdings kann ein Aspekt, die Lebensgeschichte, anhand der Histologie ihrer Knochen untersucht werden. Zu diesem Zweck wurde die diverse Sauropoden-Vergesellschaftung der oberjurassischen Tendaguru-Schichten beprobt, und zwar mit einer neuartigen Kernbohrmethode, die einen herausragenden Zugang und Einblick in die Knochenhistologie der Sauropoden ermöglichte. Wachstumsserien von Humeri und Femora sowie umfassende Überlieferungen des Wachstums von Individuen anhand einzelner Knochen machen es wahrscheinlich, daß alle vier Sauropoden-Taxa der Tendaguru-Schichten durch ein auch nach der Geschlechtsreife anhaltendes Wachstum gekennzeichnet waren. Allerdings ging das Wachstum nicht bis zum Tode des Tieres weiter, sondern kam bei einer etwas variablen Maximalgröße zum Stillstand. Fibrolamellärer Knochen ist der vorherrschende Knochentyp in den Proben, was anzeigt, daß die Tendaguru-Sauropoden mit für Säugetieren typische Raten wuchsen. Die Tendaguru-Sauropoden kombinerten also ein für Reptilien typisches Muster des Wachstums, nämlich nach der Geschlechtsreife anhaltendes Wachstum, mit für Säuger typischen Raten des Wachstums. Die verschiedenen Sauropoden-Taxa zeigen erstaunliche Unterschiede in den Details ihrer Knochenhistologie, die Unterschiede in der Lebensgeschichte belegen. Bei Barosaurus scheint außerdem ein Geschlechtsdimorphismus in der Histologie der Langknochen vorzukommen. doi:1002/mmng.1999.4860020107

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