Sperm competition and the evolution of sperm form and function in mammals

2019 ◽  
Vol 54 ◽  
pp. 14-21 ◽  
Author(s):  
Eduardo R. S. Roldan
Keyword(s):  
Sperm Competition ◽  
Form And Function ◽  
And Function

scholarly journals Sperm form and function in the absence of sperm competition

2013 ◽  
Vol 81 (3) ◽  
pp. 204-216 ◽  
Author(s):  
Gerhard van der Horst ◽  
Liana Maree
Keyword(s):  
Sperm Competition ◽  
Form And Function ◽  
And Function

scholarly journals Variability in sperm form and function in the context of sperm competition risk in two Tupinambis lizards

2014 ◽  
Vol 4 (21) ◽  
pp. 4080-4092 ◽  
Author(s):  
Cecilia S. Blengini ◽  
Naretto Sergio ◽  
Cardozo Gabriela ◽  
Laura C. Giojalas ◽  
Chiaraviglio Margarita
Keyword(s):  
Sperm Competition ◽  
Form And Function ◽  
Sperm Competition Risk ◽  
And Function

scholarly journals Sperm wars and the evolution of male fertility

Reproduction ◽  
2012 ◽  
Vol 144 (5) ◽  
pp. 519-534 ◽  
Author(s):  
Leigh W Simmons ◽  
John L Fitzpatrick
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Male Fertility ◽  
Seminal Fluid ◽  
Future Research ◽  
Sperm Length ◽  
Seminal Fluid Proteins ◽  
Control Male ◽  
Form And Function ◽  
And Function

Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

Re-examining the form and function of superstition

2011 ◽  
Author(s):  
Scott Fluke ◽  
Russell J. Webster ◽  
Donald A. Saucier
Keyword(s):  
Form And Function ◽  
And Function

A New Form and Function for Personality

2013 ◽  
Author(s):  
Joshua Wilt ◽  
William Revelle
Keyword(s):  
Form And Function ◽  
New Form ◽  
And Function
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