scholarly journals Peak shifts and extinction under sex-specific selection

2021 ◽  
Vol 17 (10) ◽  
Author(s):  
Stephen P. De Lisle
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Peak Shift ◽  
Adaptive Landscape ◽  
Population Estimates ◽  
Sexual Antagonism ◽  
Adaptive Landscapes ◽  
Quantitative Genetic ◽  
Complex Adaptive ◽  
The Face

A well-known property of sexual selection combined with a cross-sex genetic correlation ( r mf ) is that it can facilitate a peak shift on the adaptive landscape. How do these diversifying effects of sexual selection + r mf balance with the constraints imposed by such sexual antagonism, to affect the macroevolution of sexual dimorphism? Here, I extend existing quantitative genetic models of evolution on complex adaptive landscapes. Beyond recovering classical predictions for the conditions promoting a peak shift, I show that when r mf is moderate to strong, relatively weak sexual selection is required to induce a peak shift in males only. Increasing the strength of sexual selection leads to a sexually concordant peak shift, suggesting that macroevolutionary rates of sexual dimorphism may be largely decoupled from the strength of within-population sexual selection. Accounting explicitly for demography further reveals that sex-specific peak shifts may be more likely to be successful than concordant shifts in the face of extinction, especially when natural selection is strong. An overarching conclusion is that macroevolutionary patterns of sexual dimorphism are unlikely to be readily explained by within-population estimates of selection or constraint alone.

scholarly journals Peak shifts and extinction under sex-specific selection

2021 ◽  
Author(s):  
Stephen P. De Lisle
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Peak Shift ◽  
Adaptive Landscape ◽  
Population Estimates ◽  
Sexual Antagonism ◽  
Adaptive Landscapes ◽  
Quantitative Genetic ◽  
Complex Adaptive ◽  
The Face

AbstractA well-known property of sexual selection combined with a cross sex genetic correlation (rmf), is that it can facilitate a peak shift on the adaptive landscape. How do these diversifying effects of sexual selection +rmf balance with the constraints imposed by such sexual antagonism, to affect macroevolution of sexual dimorphism? Here, I extend existing quantitative genetic models of evolution on complex adaptive landscapes. Beyond recovering classical predictions for the conditions promoting a peak shift, I show that when rmf is moderate to strong, relatively weak sexual selection is required to induce a peak shift in males only. Increasing the strength of sexual leads to a sexually-concordant peak shift, suggesting that macroevolutionary rates of sexual dimorphism may be largely decoupled from the strength of within-population sexual selection. Accounting explicitly for demography further reveals that sex-specific peak shifts may be more likely to be successful than concordant shifts in the face of extinction, especially when natural selection is strong. An overarching conclusion is that macroevolutionary patterns of sexual dimorphism are unlikely to be readily explained by within-population estimates of selection or constraint alone.

Adaptive Divergence

2016 ◽  
Author(s):  
Andrew P. Hendry
Keyword(s):  
Sexual Selection ◽  
Empirical Data ◽  
Convergent Evolution ◽  
Adaptive Landscape ◽  
Adaptive Divergence ◽  
Single Population ◽  
Adaptive Landscapes ◽  
Different Populations ◽  
Key Questions

This chapter analyzes how the adaptive landscape concept can be extended from a single population in a single environment to multiple populations in multiple environments. Specifically, different environments produce different fitness peaks and divergent selection then drives different populations toward those different peaks. The chapter outlines methods for inferring adaptive divergence with respect to both phenotypes and fitness. It then turns to a review of empirical data informing several key questions about adaptive divergence in nature, including how prevalent and strong it is, how many peaks adaptive landscapes have, how predictable it is (parallel and convergent evolution), and what the role of sexual selection is in modifying adaptive divergence.

scholarly journals Independent evolution of the sexes promotes amphibian diversification

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142213 ◽  
Author(s):  
Stephen P. De Lisle ◽  
Locke Rowe
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sexual Size Dimorphism ◽  
Alternative Hypothesis ◽  
Ecological Theory ◽  
Adaptive Landscape ◽  
Extinction Rate ◽  
Independent Evolution ◽  
Threat Status ◽  
The Relationship

Classic ecological theory predicts that the evolution of sexual dimorphism constrains diversification by limiting morphospace available for speciation. Alternatively, sexual selection may lead to the evolution of reproductive isolation and increased diversification. We test contrasting predictions of these hypotheses by examining the relationship between sexual dimorphism and diversification in amphibians. Our analysis shows that the evolution of sexual size dimorphism (SSD) is associated with increased diversification and speciation, contrary to the ecological theory. Further, this result is unlikely to be explained by traditional sexual selection models because variation in amphibian SSD is unlikely to be driven entirely by sexual selection. We suggest that relaxing a central assumption of classic ecological models—that the sexes share a common adaptive landscape—leads to the alternative hypothesis that independent evolution of the sexes may promote diversification. Once the constraints of sexual conflict are relaxed, the sexes can explore morphospace that would otherwise be inaccessible. Consistent with this novel hypothesis, the evolution of SSD in amphibians is associated with reduced current extinction threat status, and an historical reduction in extinction rate. Our work reconciles conflicting predictions from ecological and evolutionary theory and illustrates that the ability of the sexes to evolve independently is associated with a spectacular vertebrate radiation.

A histological examination of the holding sacs and glandular scent organs of some bat species (Emballonuridae, Hipposideridae, Phyllostomidae, Vespertilionidae, and Molossidae)

2000 ◽  
Vol 78 (4) ◽  
pp. 613-623 ◽  
Author(s):  
William MR Scully ◽  
M B Fenton ◽  
A SM Saleuddin
Keyword(s):  
Electron Microscope ◽  
Sexual Dimorphism ◽  
Sebaceous Glands ◽  
Microscope Examination ◽  
Scent Gland ◽  
Light Microscope Level ◽  
Histological Techniques ◽  
Saccopteryx Bilineata ◽  
The Face ◽  
Scanning Electron

Using histological techniques at the light-microscope level, we examined and compared structure and sexual dimorphism of the wing sacs and integumentary glandular scent organs of 11 species of microchiropteran bats. The antebrachial wing sacs of the Neotropical emballonurids Peropteryx macrotis, Saccopteryx bilineata, and Saccopteryx leptura differed in size and location but lacked sudoriferous and sebaceous glands, confirming that they were holding sacs rather than glandular scent organs. Glandular scent organs from 11 species consisted of sebaceous and (or) sudoriferous glands in emballonurids (P. macrotis, S. bilineata, S. leptura, Taphozous melanopogon, Taphozous nudiventris), hipposiderids (Hipposiderous fulvus, Hipposiderous ater), the phyllostomid Sturnira lilium, the vespertilionid Rhogeessa anaeus, and molossids (Molossus ater and Molossus sinaloe). Glandular scent organs were located on the face (H. fulvus, H. ater), gular region (S. bilineata, P. macrotis, T. melanopogon, M. ater, M. sinaloe), chest (T. nudiventris), shoulder (S. lilium), or ears (R. anaeus). Glandular scent organs showed greater similarities within than between families, and typically were rudimentary or lacking in females. Scanning electron microscope examination revealed that the hairs associated with glandular areas of male T. melanopogon were larger and had a different cuticular-scale pattern than body hairs. These were osmetrichia, hairs specialized for holding and dispersing glandular products. In S. lilium, hairs associated with the shoulder scent-gland area were larger than body hairs but similar in cuticular-scale pattern.

Mandible: evaluation of its morphology, aging process and sexual dimorphism for aesthetic treatment purpose

2021 ◽  
Vol 5 (3) ◽  
pp. 42-46
Author(s):  
Luiz Eduardo Toledo Avelar
Keyword(s):  
Sexual Dimorphism ◽  
Bone Structure ◽  
Individual Characteristics ◽  
Mandibular Angle ◽  
Fractional Analysis ◽  
The Face ◽  
The Individual ◽  
Dynamic Quality ◽  
Base Of The Skull

The mandible is the most important bone structure of the facial makeup. Its morphology differs with respect to genetic factors, sexual dimorphism, and age. Among its particular characteristics is the ability to adapt with its counterpart, the base of the skull, conferring a dynamic quality of this bone, by the mechanism of constant remodeling. In order to understand the involvement of the mandible in the evaluation of the lower third of the face, a fractional analysis of its parts is necessary considering morphological parameters of the mandibular angle. The purpose of this study is to demonstrate the importance of the mandible as an instrument in the analysis of the lower third of the face, allowing the accomplishment of aesthetic treatment, respecting the individual characteristics.

scholarly journals Who are We, and Who (or What) Do We Want to Become? An Evolutionary Perspective on Biotransformative Technologies

2021 ◽  
Author(s):  
James Lyons-Weiler
Keyword(s):  
Human Evolution ◽  
Adaptive Landscape ◽  
Endogenous Factors ◽  
Theoretical Contribution ◽  
Organic Evolution ◽  
Adaptive Landscapes ◽  
Augmented Cognition ◽  
Language Writing ◽  
Cognitive Plasticity ◽  
The Impact

AbstractHuman evolution sits at several important thresholds. In organic evolution, interplay between exogenous environmental and genetic factors rendered new phenotypes at rates limited by genetic variation. The interplay took place on adaptive fitness landscapes determined by correspondence of genetic and environmental relationships. Human evolution involved important emergences that altered the adaptive landscape: language, writing, organized societies, science, and the internet. These endogenous factors ushered in transformative periods leading to more rapidly evolving emergences. I explore the impact of development of emerging biotransformative technologies capable of being applied to effect self-genetic modification and artificial intelligence-augmented cognition on the evolutionary landscape of phenotypes important to cognitive plasticity. Interaction effects will yield unanticipated emergences resulting in hyperrealm adaptive landscapes with more rapid evolutionary processes that feed back upon more fundamental levels while vastly outpacing organic evolution. Emerging technologies exist that are likely to impact the evolution of cognitive plasticity in humans in ways and at rates that will lead to societal upheaval. I show that the theoretical contribution of organic evolution in future human evolution is expected to become comparatively insignificant relative to that made by endogenous environmental factors such as external cognition aids and manipulation of the human genome. The results support the conclusion of a strong recommendation of a moratorium on the adoption of any technology capable of completely altering the course of human evolution.

Sexual Selection and Sexual Dimorphism in Mottled Sculpins

Evolution ◽  
1983 ◽  
Vol 37 (1) ◽  
pp. 96 ◽  
Author(s):  
Jerry F. Downhower ◽  
Luther Brown ◽  
Ronald Pederson ◽  
Gloria Staples
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism

scholarly journals Sex ratio and sexual selection in wormshrimps (Crustacea, Amphipoda, Ingolfiellidea)

2006 ◽  
Vol 75 (03-04) ◽  
pp. 189-194 ◽  
Author(s):  
Ronald Vonk ◽  
Vincent Nijman
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Habitat Use ◽  
Individual Species ◽  
Small Populations ◽  
Secondary Sexual Characters ◽  
Elusive Species ◽  
The Individual ◽  
Secondary Sexual

Small populations of several species of the groundwater dwelling amphipod genus Ingolfiella are found in caves, wells, seabottoms, beaches and riverbed interstitial habitats. To gain insight in the socio-ecology of these elusive species, we used data from collected specimens to explore the relationships between sexratios, display of secondary sexual characters and other morphological features, and habitat use. We extracted data on the sex ratios and the presence-absence of secondary sexual characters of 13 species from the literature and through examination of museum material. We found a clearly skewed sex ratio with a preponderance of females, both in the individual species as in the genus as a whole. However, sex ratio and the display of secondary sexual characters were not correlated, nor did these characters correlate with the amount of sexual dimorphism. It remains unknown why so many ingolfiellids have evolved these costly features.

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