Embryonic Development Times and Egg Retention in Four Species of Sceloporine Lizards

1992 ◽  
Vol 6 (4) ◽  
pp. 436 ◽  
Author(s):  
V. Demarco
Keyword(s):  
Embryonic Development ◽  
Egg Retention ◽  
Development Times

scholarly journals Egg retention and intrauterine embryonic development in Sceloporus aeneus (Reptilia: Phrynosomatidae): implications for the evolution of viviparity

2012 ◽  
Vol 83 (3) ◽  
Author(s):  
Rodolfo García-Collazo ◽  
Maricela Villagrán-Santa Cruz ◽  
Eduardo Morales-Guillaumin ◽  
Rubi Nelsi Meza-Lázaro ◽  
Fausto R. Méndez-de la Cruz
Keyword(s):  
Embryonic Development ◽  
Egg Retention

Population Dynamics of Limnetic Cladocera in a Beaver Pond

1975 ◽  
Vol 32 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Judith K. Kwik ◽  
John C. H. Carter
Keyword(s):  
Population Dynamics ◽  
Embryonic Development ◽  
Carrying Capacity ◽  
Sampling Errors ◽  
Beaver Pond ◽  
Bosmina Longirostris ◽  
Georgian Bay ◽  
Development Times ◽  
Different Temperatures ◽  
Ceriodaphnia Quadrangula

In a small, shallow, predation free beaver pond near Georgian Bay, Ontario Ceriodaphnia quadrangula was monacmic and Daphnia ambigua and Bosmina longirostris triacmic. Each species peaked and declined rapidly, presumably overshooting the carrying capacity of a food limited environment. Embryonic development times of each species at different temperatures was determined in the laboratory and fitted with Bĕlahrádek’s function. Calculated instantaneous rates of birth and death were normal for D. ambigua and C. quadrangula but too low to account for the rapid fluctuations in numbers of B. longirostris, suggesting occasional gross sampling errors. Bosmina longirostris may periodically abandon the limnoplankton for a benthic existence thus avoiding capture.

Clutch size influences embryonic stages at oviposition in a lizard with prolonged egg retention

2017 ◽  
Vol 38 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Thomas Foucart ◽  
Benoit Heulin ◽  
Olivier Lourdais
Keyword(s):  
Body Size ◽  
Embryonic Development ◽  
Clutch Size ◽  
Development Time ◽  
Reproductive Effort ◽  
Resource Limitation ◽  
Egg Retention ◽  
Zootoca Vivipara ◽  
Female Relative ◽  
Clutch Mass

We examined the possible interaction between reproductive effort and embryonic stages at oviposition in oviparous form of the lizard Zootoca vivipara. Our results reveal that the percentage of total embryonic development time (%TEDT) reached at oviposition is negatively correlated to clutch size (adjusted to maternal body size). We found no influence of reproductive burden of female (relative clutch mass, RCM) on %TEDT. The significant effect of fecundity supports the hypothesis that a resource limitation such as oxygen may exist for developing embryos in oviducts. The absence of RCM effect suggests that the available space (abdominal burdening of the mother) does not limit the embryonic stages at oviposition.

Temperature-dependent development in Pseudocalanus species

1989 ◽  
Vol 67 (3) ◽  
pp. 559-564 ◽  
Author(s):  
I. A. McLaren ◽  
J.-M. Sévigny ◽  
C. J. Corkett
Keyword(s):  
Embryonic Development ◽  
Residual Variance ◽  
Temperature Dependent ◽  
Species Ranges ◽  
Dependent Development ◽  
Development Times ◽  
Body Sizes ◽  
The Times ◽  
Environmental Temperatures

The duration of embryonic development and that of well-fed older stages were determined for Pseudocalanus acuspes, P. minutus, P. moultoni, and P. newmani. Excluding abnormal individuals, the times for older stages were lognormally distributed, with similar variances among species, stages, and temperatures. Some residual variance occurred among families reared together. Copepod rearings should take these sources of variance into account. Development times (D) were described well by Bělehrádek's temperature (T) function, D = a(T − α)−b, with b = 2.05 for all species from previous studies, and α and a fitted for embryonic development. Only a needed to be fitted for older stages (i.e., "equiproportional" development). Relative times to given stages at all temperatures (i.e., relative values of a) were similar in three species, but P. minutus deviated from this pattern. Values of α were directly related to presumed environmental temperatures in the species' ranges. Values of a were directly related to egg and body sizes of the different species. The temperature functions can be used to predict the lengths of the generations in these four species in nature when food is adequate.

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

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