Eutrophication causes speciation reversal in whitefish adaptive radiations

Species diversity can be lost through two different but potentially interacting extinction processes: demographic decline and speciation reversal through introgressive hybridization. To investigate the relative contribution of these processes, we analysed historical and contemporary data of replicate whitefish radiations from 17 pre-alpine European lakes and reconstructed changes in genetic species differentiation through time using historical samples. Here we provide evidence that species diversity evolved in response to ecological opportunity, and that eutrophication, by diminishing this opportunity, has driven extinctions through speciation reversal and demographic decline. Across the radiations, the magnitude of eutrophication explains the pattern of species loss and levels of genetic and functional distinctiveness among remaining species. We argue that extinction by speciation reversal may be more widespread than currently appreciated. Preventing such extinctions will require that conservation efforts not only target existing species but identify and protect the ecological and evolutionary processes that generate and maintain species.

Reversal of gender differences in Educational Attainment – historical analysis of the West German Case

Background information: During the late 1970s and the early 1980s, West Germany witnessed a reversal of gender differences in educational attainment, as females began to outperform males. Purpose: The main objective was to analyse which processes were behind the reversal of gender differences in educational attainment after 1945. The theoretical reflections and empirical evidence presented for the US context by DiPrete and Buchmann (Gender-specific trends in the value of education and the emerging gender gap in college completion, Demography 43: 1–24, 2006) and Buchmann, DiPrete, and McDaniel (Gender inequalities in education, Annual Review of Sociology 34: 319–37, 2008) are considered and applied to the West German context. It is suggested that the reversal of gender differences is a consequence of the change in female educational decisions, which are mainly related to labour market opportunities and not, as sometimes assumed, a consequence of a ‘boy’s crisis’. Sample: Several databases, such as the German General Social Survey, the German Socio-economic Panel and the German Life History Study, are employed for the longitudinal analysis of the educational and occupational careers of birth cohorts born in the twentieth century. Design and methods: Changing patterns of eligibility for university studies are analysed for successive birth cohorts and gender. Binary logistic regressions are employed for the statistical modelling of the individuals’ achievement, educational decision and likelihood for social mobility – reporting average marginal effects (AME). Results: The empirical results suggest that women’s better school achievement being constant across cohorts does not contribute to the explanation of the reversal of gender differences in higher education attainment, but the increase of benefits for higher education explains the changing educational decisions of women regarding their transition to higher education. Conclusions: The outperformance of females compared with males in higher education might have been initialised by several social changes, including the expansion of public employment, the growing demand for highly qualified female workers in welfare and service areas, the increasing returns of women’s increased education and training, and the improved opportunities for combining family and work outside the home. The historical data show that, in terms of (married) women’s increased labour market opportunities and female life-cycle labour force participation, the raising rates of women’s enrolment in higher education were – among other reasons – partly explained by their rising access to service class positions across birth cohorts, and the rise of their educational returns in terms of wages and long-term employment.

Exculpating victims and the reversal of hindsight bias

This experiment examines the role of the hindsight bias and of motivational forces such as the motive to believe in a just world as possible causes of the derogation of victims effect in the context of rape. The hindsight bias is the tendency of people to falsely believe that they would have predicted the outcome of an event once the outcome is known. Participants read descriptions of an interaction between a man and a woman that ended with one of four possible outcomes: The woman was raped with very severe consequences for her future life vs. rape with only minor consequences for her future life vs. no rape (assailant was forced to retreat by the strong defense of the victim) vs. no outcome information. To test motivational predictions the hindsight bias and the derogation effect were analyzed as a consequence of the sex of participants, the seriousness of the consequences of the rape, the belief in a just world and the acceptance of rape myths. Results supported the assumption that derogation effects are at least partly driven by hindsight bias and that motivational processes work via the hindsight bias. However, in this study we did not find a classical hindsight bias but a reversed hindsight bias: Especially female participants in the severe consequences of rape condition and those participants who did not accept rape myths rated the likelihood of rape in the rape outcome condition as smaller than participants in the no outcome information control group. They also derogated the victim less than participants in the no information control group. These effects were interpreted in terms of self-serving or in-group serving functions of the hindsight bias. Finally no support was found for the assumption that derogation effects are driven by the motive to believe in a just world.