Global distribution and evolutionary transitions of angiosperm sexual systems

2021 ◽  
Author(s):  
Yunyun Wang ◽  
Ao Luo ◽  
Tong Lyu ◽  
Dimitar Dimitrov ◽  
Xiaoting Xu ◽  
...  
Keyword(s):  
Global Distribution ◽  
Evolutionary Transitions ◽  
Sexual Systems

scholarly journals Hermaphroditism and Gonochorism

2020 ◽  
pp. 197-241
Author(s):  
Chiara Benvenuto ◽  
Stephen C. Weeks
Keyword(s):  
Reproductive System ◽  
Reproductive Strategies ◽  
Population Level ◽  
Population Densities ◽  
Ecological Constraints ◽  
Evolutionary Transitions ◽  
Colonizing Species ◽  
Sexual Systems ◽  
Theoretical Perspectives ◽  
Successful Group

This chapter compares two sexual systems: hermaphroditism (each individual can produce gametes of either sex) and gonochorism (each individual produces gametes of only one of the two distinct sexes) in crustaceans. These two main sexual systems contain a variety of alternative modes of reproduction, which are of great interest from applied and theoretical perspectives. The chapter focuses on the description, prevalence, analysis, and interpretation of these sexual systems, centering on their evolutionary transitions. The ecological correlates of each reproductive system are also explored. In particular, the prevalence of “unusual” (non-gonochoristic) reproductive strategies has been identified under low population densities and in unpredictable/unstable environments, often linked to specific habitats or lifestyles (such as parasitism) and in colonizing species. Finally, population-level consequences of some sexual systems are considered, especially in terms of sex ratios. The chapter aims to provide a broad and extensive overview of the evolution, adaptation, ecological constraints, and implications of the various reproductive modes in this extraordinarily successful group of organisms.

scholarly journals Correlated evolution of sex and reproductive mode in corals (Anthozoa: Scleractinia)

2010 ◽  
Vol 278 (1702) ◽  
pp. 75-81 ◽  
Author(s):  
Alexander M. Kerr ◽  
Andrew H. Baird ◽  
Terry P. Hughes
Keyword(s):  
Life History ◽  
Large Scale ◽  
Life History Traits ◽  
Reproductive Mode ◽  
Evolution Of Sex ◽  
Evolutionary Transitions ◽  
Evolutionary Pathway ◽  
Sexual Systems ◽  
Multicellular Organisms ◽  
Taxonomic Patterns

Sexuality and reproductive mode are two fundamental life-history traits that exhibit largely unexplained macroevolutionary patterns among the major groups of multicellular organisms. For example, the cnidarian class Anthozoa (corals and anemones) is mainly comprised of gonochoric (separate sex) brooders or spawners, while one order, Scleractinia (skeleton-forming corals), appears to be mostly hermaphroditic spawners. Here, using the most complete phylogeny of scleractinians, we reconstruct how evolutionary transitions between sexual systems (gonochorism versus hermaphrodism) and reproductive modes (brooding versus spawning) have generated large-scale taxonomic patterns in these characters. Hermaphrodites have independently evolved in three large, distantly related lineages consisting of mostly reef-building species. Reproductive mode in corals has evolved at twice the rate of sexuality, while the evolution of sexuality has been heavily biased: gonochorism is over 100 times more likely to be lost than gained, and can only be acquired by brooders. This circuitous evolutionary pathway accounts for the prevalence of hermaphroditic spawners among reef-forming scleractinians, despite their ancient gonochoric heritage.

scholarly journals Rapid dissolution of dioecy by experimental evolution

2019 ◽  
Author(s):  
G. G. Cossard ◽  
J. F. Gerchen ◽  
X. Li ◽  
Y. Cuenot ◽  
J. R. Pannell
Keyword(s):  
Experimental Evolution ◽  
Male Flower ◽  
Fold Increase ◽  
Sex Expression ◽  
Recent Analysis ◽  
Evolutionary Transitions ◽  
Sexual Systems ◽  
Major Transition ◽  
Rapid Dissolution ◽  
Male Flowers

AbstractEvolutionary transitions from hermaphroditism to dioecy have been frequent in flowering plants, but recent analysis indicates that reversions from dioecy to hermaphroditism have also been common. Here, we use experimental evolution to expose a mechanism for such reversions. We removed males from dioecious populations of the wind-pollinated plant Mercurialis annua and allowed natural selection to act on the remaining females that varied in their propensity for the occasional production of male flowers; such ‘leaky’ sex expression is common in both males and females of dioecious plants. Over only four generations, females evolved a 23-fold increase in average male-flower production. The phenotypic masculinization of females was also sufficient to render them effective at siring progeny in the presence of males. Our study illustrates the rapid dissolution of dioecy and the evolution of functional hermaphroditism under conditions that may frequently occur during periods of low population density, repeated colonization, or range expansion. It thereby experimentally validates a mechanism for a major transition in plant sexual systems..

scholarly journals Environmental stress maintains trioecy in nematode worms

2019 ◽  
Author(s):  
Ashlyn G. Anderson ◽  
Louis T. Bubrig ◽  
Janna L. Fierst
Keyword(s):  
Life History ◽  
Sex Determination ◽  
Environmental Conditions ◽  
Natural Habitat ◽  
Population Level ◽  
Evolutionary Transitions ◽  
Sexual Systems ◽  
Determination System ◽  
Stable Maintenance ◽  
Sex Determination System

AbstractSex is determined by chromosomes in mammals but it can be influenced by the environment in many worms, crustaceans and vertebrates. Despite this, there is little understanding of the relationship between ecology and the evolution of sexual systems. The nematode Auanema freiburgensis has a unique sex determination system in which individuals carrying one X chromosome develop into males while XX individuals develop into females in stress-free environments and self-fertile hermaphrodites in stressful environments. Theory predicts that trioecious populations with coexisting males, females and hermaphrodites should be unstable intermediates in evolutionary transitions between mating systems. In this article we study a mathematical model of reproductive evolution based on the unique life history and sex determination of A. freiburgensis. We develop the model in two scenarios, one where the relative production of hermaphrodites and females is entirely dependent on the environment and one based on empirical measurements of a population that displays incomplete, ‘leaky’ environmental dependence. In the first scenario environmental conditions can push the population along an evolutionary continuum and result in the stable maintenance of multiple reproductive systems. The second ‘leaky’ scenario results in the maintenance of three sexes for all environmental conditions. Theoretical investigations of reproductive system transitions have focused on the evolutionary costs and benefits of sex. Here, we show that the flexible sex determination system of A. freiburgensis may contribute to population-level resilience in the microscopic nematode’s patchy, ephemeral natural habitat. Our results demonstrate that life history, ecology and environment may play defining roles in the evolution of sexual systems.

scholarly journals Epigenetic mechanisms in sex determination and in the evolutionary transitions between sexual systems

2021 ◽  
Vol 376 (1832) ◽  
pp. 20200110 ◽  
Author(s):  
Francesc Piferrer
Keyword(s):  
Chromosome Evolution ◽  
Gene Expression Regulation ◽  
Sex Chromosome ◽  
Epigenetic Mechanisms ◽  
Sexual System ◽  
Evolutionary Transitions ◽  
Genetic Changes ◽  
Sexual Systems ◽  
Female Function ◽  
Simultaneous Hermaphrodites

The hypothesis that epigenetic mechanisms of gene expression regulation have two main roles in vertebrate sex is presented. First, and within a given generation, by contributing to the acquisition and maintenance of (i) the male or female function once during the lifetime in individuals of gonochoristic species; and (ii) the male and female function in the same individual, either at the same time in simultaneous hermaphrodites, or first as one sex and then as the other in sequential hermaphrodites. Second, if environmental conditions change, epigenetic mechanisms may have also a role across generations, by providing the necessary phenotypic plasticity to facilitate the transition: (i) from one sexual system to another, or (ii) from one sex-determining mechanism to another. Furthermore, if the environmental change lasts enough time, epimutations could facilitate assimilation into genetic changes that stabilize the new sexual system or sex-determining mechanism. Examples supporting these assertions are presented, caveats or difficulties and knowledge gaps identified, and possible ways to test this hypothesis suggested. This article is part of the theme issue ‘Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)’.

A Phylogenetic Study of Evolutionary Transitions in Sexual Systems in Australasian Wurmbea (Colchicaceae)

2008 ◽  
Vol 169 (1) ◽  
pp. 141-156 ◽  
Author(s):  
Andrea L. Case ◽  
Sean W. Graham ◽  
Terry D. Macfarlane ◽  
Spencer C. H. Barrett
Keyword(s):  
Phylogenetic Study ◽  
Evolutionary Transitions ◽  
Sexual Systems

scholarly journals The evolution of plant reproductive systems: how often are transitions irreversible?

2013 ◽  
Vol 280 (1765) ◽  
pp. 20130913 ◽  
Author(s):  
Spencer C. H. Barrett
Keyword(s):  
Wind Pollination ◽  
Reproductive Systems ◽  
Evolutionary Transitions ◽  
Sexual Systems ◽  
Form And Function ◽  
Multiple Origins ◽  
Hummingbird Pollination ◽  
Pollinator Service ◽  
And Function ◽  
Pollination Systems

Flowering plants are characterized by striking variation in reproductive systems, and the evolutionary lability of their sexual traits is often considered a major driver of lineage diversification. But, evolutionary transitions in reproductive form and function are never entirely unconstrained and many changes exhibit strong directionality. Here, I consider why this occurs by examining transitions in pollination, mating and sexual systems, some of which have been considered irreversible. Among pollination systems, shifts from bee to hummingbird pollination are rarely reversible, whereas transitions from animal to wind pollination are occasionally reversed. Specialized pollination systems can become destabilized through a loss of pollinator service resulting in a return to generalized pollination, or more commonly a reliance on self-pollination. Homomorphic and heteromorphic self-incompatibility systems have multiple origins but breakdown to self-compatibility occurs much more frequently with little evidence for subsequent gains, at least over short time-spans. Similarly, numerous examples of the shift from outcrossing to predominant self-fertilization are known, but cases of reversal are very limited supporting the view that autogamy usually represents an evolutionary dead-end. The evolution of dioecy from hermaphroditism has also been considered irreversible, although recent evidence indicates that the occurrence of sex inconstancy and hybridization can lead to the origin of derived sexual systems from dioecy. The directionality of many transitions clearly refutes the notion of unconstrained reproductive flexibility, but novel adaptive solutions generally do not retrace earlier patterns of trait evolution.

scholarly journals Ecological genetics of sex ratios in plant populations

2010 ◽  
Vol 365 (1552) ◽  
pp. 2549-2557 ◽  
Author(s):  
Spencer C. H. Barrett ◽  
Sarah B. Yakimowski ◽  
David L. Field ◽  
Melinda Pickup
Keyword(s):  
Charles Darwin ◽  
Empirical Studies ◽  
Sex Ratios ◽  
Ecological Genetics ◽  
Plant Populations ◽  
Dioecious Species ◽  
Evolutionary Transitions ◽  
Sexual Systems ◽  
Genetic Mechanisms ◽  
Angiosperm Species

In many angiosperm species, populations are reproductively subdivided into distinct sexual morphs including females, males and hermaphrodites. Sexual polymorphism is maintained by frequency-dependent selection, leading to predictable sex ratios at equilibrium. Charles Darwin devoted much of his book ‘ The Different Forms of Flowers on Plants of the Same Species ’ (1877) to investigating plant sexual polymorphisms and laid the foundation for many problems addressed today by integrating theory with empirical studies of the demography and genetics of populations. Here, we summarize our recent work on the ecological and genetic mechanisms influencing variation in sex ratios and their implications for evolutionary transitions among sexual systems. We present the results of a survey of sex ratios from 126 species from 47 angiosperm families and then address two general problems using examples from diverse angiosperm taxa: (i) the mechanisms governing biased sex ratios in dioecious species; (ii) the origins and maintenance of populations composed of females, males and hermaphrodites. Several themes are emphasized, including the importance of non-equilibrium conditions, the role of life history and demography in affecting sex ratios, the value of theory for modelling the dynamics of sex ratio variation, and the utility of genetic markers for investigating evolutionary processes in sexually polymorphic plant populations.

Global distribution of species diversity in vascular plants: Towards a world map of phytodiversity

Erdkunde ◽  
1996 ◽  
Vol 50 (1) ◽  
Author(s):  
Wilhelm Barthlott ◽  
et al.
Keyword(s):  
Species Diversity ◽  
Vascular Plants ◽  
Global Distribution
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