Evolucijsko posebne vrste običajno predstavljajo več filogenetske raznolikosti, kot je pričakovano

Evolucijska posebnost meri, koliko se določena vrsta evolucijsko razlikuje v svoji filogenetski veji. Nedavno so bile za določanje prioritet pri ohranjanju biotske raznolikosti predlagane mere, ki so eksplicitno vključujejo časovno komponento. Vendar ugotavljamo, da se takšne mere kakovostno razlikujejo glede na to, kako dobro zaobjamejo skupno evolucijo (poimenovano kot filogenetsko raznolikost), ki jo predstavlja izbrana množica vrst. S pomočjo simulacij in preproste teorije grafov smo raziskali ta odnos glede na obliko filogenetskega drevesa. Pokazali smo, da mere posebnosti zaobjamejo več filogenetske raznolikosti na neuravnoteženih drevesih in na drevesih z veliko cepitvami blizu sedanjosti. Vrstni red glede na mero posebnosti je bil robusten neodvisno od oblike dreves, pri čemer so se proporcionalne mere obnašale bolje od mer, osnovanih na vozlišcih dreves. Enak vzorec se je izkazal na primeru 50 ultrametričnih dreves iz literature. Tako lahko zaključimo, da so mere posebnosti lahko koristen dodatni indikator pri določanju prioritet ohranjanja vrst. Najenostavnejša mera, starost vrste, se v tem kontekstu izkaže presenetljivo dobro, kar nakazuje da nove mere, ki se osredotočijo na obliko drevesa pri konicah, lahko zagotovijo transparentno alternativo za bolj zapletene pristope, ki obravnavajo polna drevesa.Evolutionary distinctiveness measures of how evolutionarily isolated a speciesis relative to other members of its clade. Recently, distinctiveness metrics that explicitly incorporate time have been proposed for conservation prioritization. However, we found that such measures differ qualitatively in how well they capture the total amount of evolution (termed phylogenetic diversity, or PD) represented by a set of species. We used simulation and simple graph theory to explore this relationship with reference to phylogenetic tree shape. Overall, the distinctiveness measures capture more PD on more unbalanced trees and on trees with many splits near the present. The rank order of performance was robust across tree shapes, with apportioning measures performing best and node-based measures performing worst. A sample of 50 ultrametric trees from the literature showed the same patterns. Taken together, this suggests that distinctiveness metrics may be a useful addition to other measures of value for conservation prioritization of species. The simplest measure, the age of a species, performed surprisingly well, suggesting that new measures that focus on tree shape near the tips may provide a transparent alternative to more complicated full-tree approaches

It’s okay to shoot a character: Moral disengagement in violent video games

What makes virtual violence enjoyable rather than aversive? Two 2×2 experiments tested the assumption that moral disengagement cues provided by a violent video game's narrative and game play lessen users' guilt and negative affect, which would otherwise undermine players' enjoyment of the game. Experiment 1 found that users' familiarity with the violent game reduced guilt and negative affect, and enhanced enjoyment, whereas opponents' nonhuman outer appearance and blameworthiness had no effect. Experiment 2 found that fighting for a just purpose, perceiving less mayhem, and framing the overall situation as " just a game" or " just an experiment" reduced guilt and negative affect, whereas the distorted portrayal of consequences did not. Effects on game enjoyment were mixed and suggest that moral disengagement cues may both foster and diminish game enjoyment. © 2010 International Communication Association