Over the last 20 years, Chinese attitudes to sex have undergone a revolution - a process carefully observed, and sometimes encouraged, by the country's first female sexologist, Li Yinhe. It's one of many rapid changes she has recorded in her career. She uses the word "revolution" herself and it's easy to see why. Until , sex before marriage was actually illegal and could be prosecuted as "hooliganism".
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Sexual Reproduction and the Evolution of Sex | Learn Science at Scitable
Most empirical and theoretical studies have shown that sex increases the rate of evolution, although evidence of sex constraining genomic and epigenetic variation and slowing down evolution also exists. Faster rates with sex have been attributed to new gene combinations, removal of deleterious mutations, and adaptation to heterogeneous environments. Slower rates with sex have been attributed to removal of major genetic rearrangements, the cost of finding a mate, vulnerability to predation, and exposure to sexually transmitted diseases. Whether sex speeds or slows evolution, the connection between reproductive mode, the evolutionary rate, and species diversity remains largely unexplored. Here we present a spatially explicit model of ecological and evolutionary dynamics based on DNA sequence change to study the connection between mutation, speciation, and the resulting biodiversity in sexual and asexual populations. We show that faster speciation can decrease the abundance of newly formed species and thus decrease long-term biodiversity.
Faster lizards sire more offspring: sexual selection on whole-animal performance
Sexual selection operates by acting on variation in mating success. However, since selection acts on whole-organism manifestations i. Previous studies have revealed positive relationships between performance and survival, that is, natural selection, but none have explicitly tested whether performance may influence reproductive success through more matings , that is, sexual selection.
This page has been archived and is no longer updated. Birds do it, and bees do it. Indeed, researchers estimate that over But why is sexual reproduction so commonplace?