Evolutionary thinking among biology students in a third world country

Abstract Background Evolutionary thinking is traditionally directly related to education and inversely to religiosity. Accordingly, biology students are naturally expected to be more prone to naturalist evolution due to their close contact with this theory and high scientific literacy. To test this, we performed a cross-national study surveying biology students’ evolutionary opinions in Brazil, contrasting the proportions of creationism (Cr), divinely guided evolution (DGE) and naturalist evolution (NaE). Results We found that NaE comprised 44.4%, DGE 43.3%, and Cr 12.3% of students’ opinions. NaE was higher among postgraduate than undergraduate students. There were marked geographic differences, with NaE peaking in the most socioeconomically developed regions and Cr in the less. Opinions related to divine influence as a whole (Cr + DGE) became more likely as the score of students’ institutions decreased (i.e. institutions with lower-quality standards). Conclusions Most biology students paradoxically do not have NaE as an explanation (55.6%), a high proportion given their presumed contact with the theory. We demonstrate that socioeconomic and institution quality factors are apparently important in determining the evolutionary thinking patterns. NaE paucity among biology students may also be influenced by low scientific literacy and the extreme religiosity of the population, which incorporates divine influence in students’ opinions long before they have any contact with evolutionary theory

Sink Status and Photosynthetic Rate of the Leaflet Galls Induced by Bystracoccus mataybae (Eriococcidae) on Matayba guianensis (Sapindaceae)

The galling insect Bystracoccus mataybae (Eriococcidae) induces green and intralaminar galls on leaflets of Matayba guianensis (Sapindaceae), and promotes a high oxidative stress in host plant tissues. This biotic stress is assumed by the histochemical detection of hydrogen peroxide, a reactive oxygen species (ROS), whose production alters gall physiology. Thus, we hypothesize that high levels of nutrients are accumulated during gall development in response to a local maintenance of photosynthesis and to the galling insect activity. Moreover, the maintenance of low levels of photosynthesis may guarantee O2 production and CO2 consumption, as well as may avoid hypoxia and hypercarbia in gall tissues. To access the photosynthesis performance, the distribution of chlorophyllous tissues and the photochemical and carboxylation rates in gall tissues were analyzed. In addition, histochemical tests for hydrogen peroxide and phenolic derivatives were performed to confirm the biotic stress, and set the possible sites where stress dissipation occurs. The contents of sugars and nitrogen were evaluated to quantify the gall sink. Currently, we assume that the homeostasis in gall tissues is ruptured by the oxidative stress promoted by the galling insect activity. Thus, to supply the demands of gall metabolism, the levels of water-soluble polysaccharides and starch increase in gall tissues. The low values of maximum quantum efficiency of PSII (Fv/Fm) indicate a low photosynthetic performance in gall tissues. In addition, the decrease of PSII operating efficiency, (F’m–F’)/F’m, and Rfd (instantaneous fluorescence decline ratio in light, to measure tissue vitality) demonstrate that the tissues of B. mataybae galls are more susceptible to damage caused by stressors than the non-galled tissues. Thus, the high oxidative stress in gall developmental sites is dissipated not only by the accumulation of phenolic derivatives in the protoplast, but also of lignins in the walls of neoformed sclereids