Browsing by Subject "selection"

Now showing 1 - 3 of 3
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    Open Access
    Environmental correlates of geographic divergence in a phenotypic trait: A case study using bat echolocation
    (Wiley, 2017-06-28) Maluleke, Tinyiko; Jacobs, David S; Winker, Henning
    Divergence in phenotypic traits may arise from the interaction of different evolutionary forces, including different kinds of selection (e.g., ecological), genetic drift, and phenotypic plasticity. Sensory systems play an important role in survival and reproduction, and divergent selection on such systems may result in lineage diversification. Such diversification could be largely influenced by selection in different environments as a result of isolation by environment (IbE). We investigated this process using geographic variation in the resting echolocation frequency of the horseshoe bat species, Rhinolophus damarensis, as a test case. Bats were sampled along a latitudinal gradient ranging from 16°S to 32°S in the arid western half of southern Africa. We measured body size and peak resting frequencies (RF) from handheld individual bats. Three hypotheses for the divergence in RF were tested: (1) James’ Rule, (2) IbE, and (3) genetic drift through isolation by distance (IbD) to isolate the effects of body size, local climatic conditions, and geographic distance, respectively, on the resting frequency of R. damarensis. Our results did not support genetic drift because there was no correlation between RF variation and geographic distance. Our results also did not support James’ Rule because there was no significant relationship between (1) geographic distances and RF, (2) body size and RF, or (3) body size and climatic variables. Instead, we found support for IbE in the form of a correlation between RF and both region and annual mean temperature, suggesting that RF variation may be the result of environmental discontinuities. The environmental discontinuities coincided with previously reported genetic divergence. Climatic gradients in conjunction with environmental discontinuities could lead to local adaptation in sensory signals and directed dispersal such that gene flow is restricted, allowing lineages to diverge. However, our study cannot exclude the role of processes like phenotypic plasticity in phenotypic variation.
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    Open Access
    A new selection model for the academic development programme for engineering at UCT
    (SASEE, 2018-02-16) Campbell, Anita; Craig, Tracy S; le Roux, Pierre
    The Academic Support Programme for Engineering at the University of Cape Town (ASPECT) has operated under a slowly evolving model since its inception in 1989. Different models of access and curriculum are frequently under consideration and in 2014 we had the opportunity to put into practice a new model, involving self-selection and delayed transition into ASPECT driven by first term assessment. In this paper we present a historical overview, reflect on the 2014 experiences of students and staff in light of relevant theory and conclude with an argument in favour of the delayed transition model.
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    Open Access
    Tell me about your (Facebook) self: recruiter personality traits and accuracy of personality judgement of candidate Facebook profiles
    (2018) Rauch, Philippa; de Kock, Francois
    The use of social networking sites, such as Facebook, in the job application screening process has changed the recruitment landscape. Many human resource (HR) professionals and recruiters have begun to use social networking sites as a tool to attract, source and screen potential candidates. When screening candidates’ Facebook profiles, recruiters make personality judgements that have important consequences for hiring decisions. However, little is known about what makes a good judge of personality in the world of online screening for recruitment. This study investigated the relationship between recruiters’ Big Five personality traits (extraversion, agreeableness, conscientiousness, openness to experience and neuroticism) and their ability to judge accurately candidates’ personality traits from their Facebook profiles. In particular, distinctive accuracy measures were employed which account for personality profile normativeness, or the degree to which applicants being rated are generally alike – an important limitation of earlier profile accuracy measures. Results from 456 university students who judged five actual Facebook profiles for which ‘true score’ estimates on personality traits were possible, revealed that recruiters were generally able to infer applicants’ personality traits from their Facebook profiles. However, recruiter personality was not an important factor in their judgement accuracy, neither when accuracy was operationalised as traditional profile accuracy measures, nor as distinctive accuracy.