Month: September 2022

DIOECY DEFINED. “Dioecy (Greek: διοικία "two households"; adjective form: dioecious) is a characteristic of a species, meaning that it has distinct male and female individual organisms. Dioecious reproduction is biparental reproduction. Dioecy is one method that excludes self-fertilization and promotes allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Flowering plants have several other methods of excluding self-fertilization, called Self-incompatibility.” https://lnkd.in/dKd4E5r View in LinkedIn

DIOECY IN ANIMALS. “Dioecy may also describe colonies, such as the colonies of Siphonophorae (Portuguese man-of-war), which may be either dioecious within a species or monoecious. Dioecious colonies contain members of only one sex, whereas monoecious colonies contain members of both sexes. Most animal species are dioecious (gonochoric).” https://lnkd.in/dKd4E5r View in LinkedIn

RISKS OF DIOECY. “Separating sexual function between different individuals carries risks, especially for sedentary organisms. Nevertheless, many land plants have unisexual gametophytes or sporophytes.” https://lnkd.in/dUmPa47 View in LinkedIn

DIOECY. “Dioecious plants, however fertilised, have a great advantage over other plants in their cross-fertilisation being assured. But this advantage is gained ... with some risk ... of their fertilisation occasionally failing. Half the individuals, moreover, namely, the males, produce no seed, and this might possibly be a disadvantage... dioecious plants cannot spread so easily as monoecious and hermaphrodite species, for a single individual, which happened to reach some new site, could not propagate its kind.” https://lnkd.in/dUmPa47 View in LinkedIn

FREQUENCY. “There are 15 600 dioecious angiosperms in 987 genera and 175 families, or 5–6% of the total species (7% of genera, 43% of families), with somewhere between 871 to 5000 independent origins of dioecy. Some 43% of all dioecious angiosperms are in just 34 entirely dioecious clades, arguing against a consistent negative influence of dioecy on diversification.” https://lnkd.in/dUmPa47 View in LinkedIn

LABILE AND UNCONSTRAINED. "The occurrence of different mechanisms of clonal reproduction among related species suggests that clonal strategies are relatively labile and that their evolution is not strongly constrained." http://www.pnas.org/content/112/29/8859.full View in LinkedIn

IMPACT. "The widespread occurrence in dioecious species of both sexual and clonal reproduction provides an opportunity to investigate how these two reproductive modes interact to influence sex ratios and fitness in plant populations." http://www.pnas.org/content/112/29/8859.full View in LinkedIn

SEX RATIOS. Populations usually strive to generate equal numbers of each sex, but extreme deviations from this condition do occur quite frequently. Read this fascinating article about these deviations from the assumed norm. https://lnkd.in/e2CjiWF View in LinkedIn

SEEDS AND STERILITY. "Very low seed production and even complete sterility are common features of clonal plant populations. Sterility can be caused by a variety of environmental and genetic factors influencing various stages in the process of sexual reproduction." http://www.pnas.org/content/112/29/8859.full View in LinkedIn

INVASIVE NEUTERING. "Long-distance dispersal of only one mating type to a region, especially in invasive species, may disable sexual systems, resulting in sterility." http://www.pnas.org/content/112/29/8859.full View in LinkedIn