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sexual reproduction

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Figure  4 —<b>Sexual</b> <b>reproductive</b> morphology in  Metrarabdotos colligatum,  Ce...
Published: 01 May 2001
Figure 4 —Sexual reproductive morphology in Metrarabdotos colligatum, Cercado Formation, Upper Miocene, Rio Mao, Dominican Republic. 1, Ovicelled zooids and surrounding ordinary autozooids, USNM 509422, locality NMB 16918; 2, 3, frontal and lateral views of ancestrular zooids and succeeding
Journal Article
Published: 01 May 2001
Journal of Paleontology (2001) 75 (3): 564-577.
...Figure 4 —Sexual reproductive morphology in Metrarabdotos colligatum, Cercado Formation, Upper Miocene, Rio Mao, Dominican Republic. 1, Ovicelled zooids and surrounding ordinary autozooids, USNM 509422, locality NMB 16918; 2, 3, frontal and lateral views of ancestrular zooids and succeeding...
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Journal Article
Published: 01 January 2007
Journal of Foraminiferal Research (2007) 37 (1): 41-45.
... that united during sexual reproduction (i.e., plastogamic reproduction). This suggests the possibility that plastogamic sexual reproduction occurred in some fossil nummulitids. 20 06 2006 13 01 2005 © 2007 Journal of Foraminiferal Research 2007 F igure 1. Locations of the conjoined tests...
FIGURES
Journal Article
Published: 01 January 2015
Journal of Paleontology (2015) 89 (1): 28-50.
.... Conspecific biologically, each morphotype represents an asexual (resting cyst) or sexual (zygotic cyst) stage in the life cycle, respectively. We reconstruct this hypothetical life cycle and infer that the organism demonstrates a reproductive strategy of alternation...
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Journal Article
Journal: Palynology
Published: 01 March 2016
Palynology (2016) 40 (1): 83-121.
... identification of the double wall of the vesicle. Based on the earliest occurrence of microfossils with an internal body in the Dictyosphaera–Shuiyousphaeridium plexus, sexual reproduction among photosynthesising microbiota is interpreted at c. 1.6–1.4 Ga, a common phenomenon in the Ediacaran (Tanarium...
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Journal Article
Published: 01 March 2012
Journal of Paleontology (2012) 86 (2): 268-272.
...Yuki Tokuda; Yoichi Ezaki AbstractTruncatoflabellum has been considered a free-living genus that exhibits both sexual and asexual phases; divided lower coralla (anthocauli) are specialized for asexual reproduction by transverse division through a decalcification process, whereas the upper coralla...
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Journal Article
Journal: GSA Bulletin
Published: 01 April 1976
GSA Bulletin (1976) 87 (4): 633-639.
... atmosphere. Genetic recombination resulting from sexual reproduction, with nuclear fusion and meiosis, first appeared in red or green algae at some time within the succeeding 1 b.y. Geological Society of America 1976 Eosphaera Eucapsism Huroniospora Palaeocryptidium oldest eucaryotes Precambrian...
Journal Article
Journal: Paleobiology
Published: 01 January 2000
Paleobiology (2000) 26 (3): 386-404.
.... The selective advantages of complex multicellularity are considered sufficient for it to have arisen immediately following the appearance of sexual reproduction. As such, the most reliable proxy for the first appearance of sex will be the first stratigraphic occurrence of complex multicellularity.Bangiomorpha...
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Journal Article
Published: 01 January 1999
Journal of Foraminiferal Research (1999) 29 (1): 75-84.
...V. Stouff; M. Lesourd; J.-P. Debenay AbstractThe production of several successive generations of megalospheric schizonts, alternating with phases of sexual reproduction, was observed in laboratory cultures of Ammonia tepida. The isolation of megalospheric schizonts facilitated observations...
Journal Article
Published: 01 April 2012
Journal of Foraminiferal Research (2012) 42 (2): 143-150.
... variations in size, frequency distribution, and abundance indicate that this population reproduced primarily during the summer (July–September), when both asexual and sexual reproduction occurred simultaneously, suggesting a predominantly coeval, one-year life span for each generation. However, a modest...
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Journal Article
Published: 01 April 2012
Journal of Foraminiferal Research (2012) 42 (2): 143-150.
... variations in size, frequency distribution, and abundance indicate that this population reproduced primarily during the summer (July–September), when both asexual and sexual reproduction occurred simultaneously, suggesting a predominantly coeval, one-year life span for each generation. However, a modest...
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Journal Article
Published: 01 April 2010
Journal of Micropalaeontology (2010) 29 (1): 81-85.
... and sexual reproduction might not be irreversible. 5 10 2009 25 1 2010 © 2010 The Micropalaeontological Society 2010 Ostracoda evolution eyes ancient asexuals dormant genes References Ayress , M.A. , Whatley , R.C. , Downing , S.E. & Millson , K.J. 1995 . Cainozoic...
Journal Article
Published: 01 January 1998
Journal of Foraminiferal Research (1998) 28 (1): 66-75.
.... tuvaluensis test holds the latter firmly in position and may eventually completely envelope it. Sexual reproduction of M. tuvaluensis is by plastogamy in place on the miliolid test, involving two or more gamonts of unequal size, and the miliolid probably survives this. The relationship may be a fortuitous one...
Image
Figure  5 —<b>Sexual</b> and asexual <b>reproductive</b> morphology in  Metrarabdotos  n....
Published: 01 May 2001
Figure 5 —Sexual and asexual reproductive morphology in Metrarabdotos n. sp. 11, Paraguana Formation, Lower Pliocene, Venezuela. 1, Lateral view of young colony showing ancestrular tetrad and succeeding erect zooids before development of obscuring extrazooidal calcification, USNM 509425; 2
Journal Article
Journal: Paleobiology
Published: 22 August 2017
Paleobiology (2017) 43 (4): 620-641.
... substantial evolutionary changes in dimorphism in only one species, Haplocytheridea renfroensis. Several lines of evidence indicate that patterns of sexual dimorphism in these ostracodes reflect male investment in reproduction, suggesting that this study system has the potential to capture variation in sexual...
Journal Article
Journal: Geology
Published: 01 March 2017
Geology (2017) 45 (3): 199-202.
...Thomas A. Hegna; Markus J. Martin; Simon A.F. Darroch AbstractDespite a plethora of exceptionally preserved trilobites, trilobite reproduction has remained a mystery. No previously described trilobite has unambiguous eggs or genitalia preserved. This study reports the first occurrence of in situ...
FIGURES
Series: The Micropalaeontological Society, Special Publications
Published: 01 January 2013
DOI: 10.1144/TMS5.21
EISBN: 9781862396500
... and a reproductively active coccoid stage. The sexual cycle is characterized by heterogamous anisogamy and includes a sexual benthic hypnozygote. The first apical plate in vegetative cells does not touch the apical pore plate while in gametes it does, confirming in Fragilidium the homology of what is frequently...
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Journal Article
Published: 01 July 2012
Journal of Micropalaeontology (2012) 31 (2): 121-129.
... also established that test dimorphism is not related to sex but to the asexual and sexual phases of reproduction. * (e-mail: jwm1@noc.soton.ac.uk ) 6 12 2011 10 1 2012 © 2012 The Micropalaeontological Society 2012 foraminifera dimorphism life cycle history of research The life cycle...
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Journal Article
Published: 01 September 2002
Journal of Paleontology (2002) 76 (5): 810-821.
... appear to represent mass mortality events resulting from a semelparous reproductive strategy. Arkanites relictus occurs as a dimorphic pair (depressed, widely umbilicate, cadiconic conchs and compressed, narrowly umbilicate, pachyconic conchs) thought to reflect sexual dimorphism. Late stage ontogenetic...
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Journal Article
Journal: Palynology
Published: 01 June 2011
Palynology (2011) 35 (1): 103-145.
... and vegetative cells. They represent the Chlorophytes in the class Prasinophyceae, which reproduce asexually (forming resting phycoma cysts), and Chlorophyceae, which reproduce sexually (zygotic cysts). Some species had a complex life cycle, with alternating vegetative and reproductive generations that differed...
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