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- Androdioecy (2)
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Articles 1 - 6 of 6
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Guided Inquiry Lab Exercises In Development And Oxygen Consumption Using Zebrafish, Brian Bagatto
Guided Inquiry Lab Exercises In Development And Oxygen Consumption Using Zebrafish, Brian Bagatto
Biology Faculty Research
Zebrafish have become a model organism in many areas of research and are now being used with more frequency in the classroom to teach important biological concepts. The two guided inquiry exercises in this article are each aimed at a different level of instruction, but each can be modified to fit the needs of many high school or college-level courses. The "Zebrafish Development and Environment'' exercise teaches high school students about zebrafish development by presenting a series of embryos at different ages. Without access to visual references, students are asked to rank developing zebrafish by age and explain their choices. …
Effects Of Microzooplankton Growth And Trophic Interactions On Herbivory In Coastal And Offshore Environments, Matthew R. First, Harlan L. Miller Iii, Peter J. Lavrentyev, James L. Pinckney, Adrian B. Burd
Effects Of Microzooplankton Growth And Trophic Interactions On Herbivory In Coastal And Offshore Environments, Matthew R. First, Harlan L. Miller Iii, Peter J. Lavrentyev, James L. Pinckney, Adrian B. Burd
Biology Faculty Research
We performed serial dilution experiments to estimate rates of gross phytoplankton growth (L) and grazing mortality (m) in both eutrophic (Corpus Christi Bay, Texas, USA) and oligotrophic (offshore Gulf of Mexico) waters. Two parallel experiments were performed in both environments, with seawater pre-screened through 153 or 25 Inn mesh to observe the responses of microzooplankton (MZP) to dilution treatments. MZP biomass changed over the duration of the experimental incubations; in several treatments, MZP net growth rates were >1 d(-1). Patterns of growth varied between dilutions and initial screening size. In the eutrophic system, the ratio of phytoplankton grazing mortality rate …
Avian Incubation Inhibits Growth And Diversification Of Bacterial Assemblages On Eggs, Matthew D. Shawkey, Mary K. Firestone, Eoin L. Brodie, Steven R. Beissinger
Avian Incubation Inhibits Growth And Diversification Of Bacterial Assemblages On Eggs, Matthew D. Shawkey, Mary K. Firestone, Eoin L. Brodie, Steven R. Beissinger
Biology Faculty Research
Microbial infection is a critical source of mortality for early life stages of oviparous vertebrates, but parental defenses against infection are less well known. Avian incubation has been hypothesized to reduce the risk of trans-shell infection by limiting microbial growth of pathogenic bacteria on eggshells, while enhancing growth of commensal or beneficial bacteria that inhibit or competitively exclude pathogens. We tested this hypothesis by comparing bacterial assemblages on naturally incubated and experimentally unincubated eggs at laying and late incubation using a universal 16S rRNA microarray containing probes for over 8000 bacterial taxa. Before treatment, bacterial assemblages on individual eggs from …
Which Sry Locus Is The Hypertensive Y Chromosome Locus?, Monte E. Turner, Joel Farkas, Jeff Dunmire, Daniel Ely, Amy Milsted
Which Sry Locus Is The Hypertensive Y Chromosome Locus?, Monte E. Turner, Joel Farkas, Jeff Dunmire, Daniel Ely, Amy Milsted
Biology Faculty Research
The Y chromosome of the spontaneously hypertensive rat (SHR) contains a genetic component that raises blood pressure compared with the Wistar-Kyoto (WKY) Y chromosome. This research tests the Sry gene complex as the hypertensive component of the SHR Y chromosome. The Sry loci were sequenced in 1 strain with a hypertensive Y chromosome (SHR/Akr) and 2 strains with a normotensive Y chromosome (SHR/Crl and WKY/Akr). Both SHR strains have 7 Sry loci, whereas the WKY strain has 6. The 6 loci in common between SHR and WKY strains were identical in the sequence compared (coding region, 392-bp 5' prime flanking, …
Can Males Successfully Invade Hermaphroditic Populations Of Clam Shrimp (Eulimnadia Texana)?, Stephen C. Weeks
Can Males Successfully Invade Hermaphroditic Populations Of Clam Shrimp (Eulimnadia Texana)?, Stephen C. Weeks
Biology Faculty Research
Androdioecy (mixtures of males and hermaphrodites) is distinguished by its rarity, being found in only similar to 40 animal species. Many of these species are clam shrimp in the genus Eulimnadia. A metapopulation model for the maintenance of androdioecy is tested herein by examining male success in aquaria with a single male-producing hermaphrodite introduced into an otherwise all-hermaphrodite population. This migration experiment did allow males to persist in these populations for seven generations, although at levels below those found in other populations of these shrimp. These results suggest that the maintenance of androdioecy via 'reproductive assurance' is unlikely by way …
Inbreeding Effects On Sperm Production In Clam Shrimp (Eulimnadia Texana), Stephen C. Weeks, Sadie K. Reed, Donald W. Ott, Franca Scanabissi
Inbreeding Effects On Sperm Production In Clam Shrimp (Eulimnadia Texana), Stephen C. Weeks, Sadie K. Reed, Donald W. Ott, Franca Scanabissi
Biology Faculty Research
Hypothesis: Inbreeding depression is manifest in lower sperm production. Organism: Freshwater crustaceans (clam shrimp - Eulimnadia texana), from the southwestern United States, which have high levels of inbreeding. Methods: Comparisons of semi-thin sections of the male gonad among selfed and outcrossed siblings from four families. Results: There was a twofold reduction in sperm production in inbred relative to outcrossed males. Inbreeding depression in males was higher than previous estimates from hermaphrodites. Conclusions: Inbreeding markedly reduces sperm production. The observed low levels of sperm production can explain both the low average outcrossing rates as well as the variation in these rates …