Influence of sociocultural factors and acceptance of Creationism in the comprehension of evolutionary Biology in freshman brazilian students

The creationist movements in Brazil, although considered weak, are on the increase. The Brazilian legislation neither imposes any objection in teaching evolution nor obliges the teaching of creationism as an alternative to evolution in science classes. Furthermore, it allows the optional teaching of religion at schools. The aim of the present study was to evaluate the knowledge regarding biological evolution in freshman students from a Brazilian university. Such knowledge was related to sociocultural factors such as their parental education level, the type of high school the student graduated from (private or public school), their philosophical/religious position as well as the acceptance of creationism as an alternative to evolution. Among those factors, the latter two showed significant differences, in which the higher averages belonged both to the atheistic students and to those who do not accept creationism as an alternative to evolution

Misconceptions about evolution in brazilian freshmen students

Regarding such an important issue as our origin, as well as the origin of all biological diversity, it is surprising to realize that evolution still faces drawbacks in keeping its deserved notability as a unifying theory in biology. This does not happen because evolutionism lacks validity as a scientific theory, but rather because of several misconceptions regarding evolutionary biology that were and continue to be found in elementary and secondary education. Furthermore, mistaken evolutionary ideas also affect some philosophical and social issues. The aim of the present study was to evaluate knowledge about evolution among freshman students from distinct majoring areas at Universidade Estadual do Centro-Oeste do Paraná (UNICENTRO), Brazil. The research was carried out based on aten-question questionnaire about evolution with distinct levels of difficulty, comprising the most observed misconceptions. In this study, 231 students attending classes in biological sciences (morning and evening schedule), exact sciences (agronomy, physics, chemistry, and math), and human sciences (history, geography, and pedagogy) were interviewed. The total average of right answers was 48.8%, and the highest average per course obtained was 58.7% from the students attending biological sciences (evening schedule). Although evolutionary biology and ecology are supposed to represent teaching guide issues according to the recommendations of the National Curricular Parameters for the Secondary School, the data obtained suggest that the evidence for evolution, the role of natural selection and random events, as well as the sources of variation, must be better focused at schools

Parallel evolution evidenced by molecular data in the banded- tetra (Astyanax fasciatus)

Astyanax is well known as a model for developmental biology studies, particularly with regard to Mexico's cave populations. More than 130 species of Astyanax are already known, most of which live in South America. The occurrence of cryptic species and species complexes elucidated by chromosomal and genetic studies demonstrates that the relationship between morphology and molecular evolution is quite complex within this group. In this work, we demonstrate that morphology does not follow the path of vicariant processes observed in Astyanax fasciatus populations, which separated about three million years ago, although molecular data suggests its separation in two species

Astyanax bockmanni Vari and Castro, 2007: an ambiguous karyotype in the Astyanax genus

Despite the widespread distribution of Astyanax bockmanni in streams from Upper Paraná River system in central, southeastern, and southern Brazil, just recently, it has been identified as a distinct Astyanax species. Cytogenetic studies were performed in two populations of this species, revealing conservative features. A. bockmanni shows 2n = 50 chromosomes, a karyotypic formula composed of 10 M + 12SM + 12ST + 16A and multiple Ag-NORs. Eight positive signals in subtelocentric/acrocentric chromosomes were identified by fluorescent in situ hybridization (FISH) with 18S rDNA probes. After FISH with 5S rDNA probes, four sites were detected, comprising the interstitial region of a metacentric pair and the terminal region on long arms of another metracentric pair. Little amounts of constitutive heterochromatin were observed, mainly distributed at distal region in two chromosomal pairs. Additionally, heterochromatin was also located close to the centromeres in some chromosomes. No positive signals were detected in the chromosomes of A. bockmanni by FISH with the As-51 satellite DNA probe. The studied species combines a set of characteristics previously identified in two different Astyanax groups. The chromosomal evolution in the genus Astyanax is discussed

Biogeographic patterns in the chromosomal distribution of a satellite DNA in the banded tetra Astyanax fasciatus (Teleostei: Characiformes)

The As-51 satellite DNA is a transposon-like sequence formerly described for arthropods and physically identifiable by fluorescent in situ hybridization. In the present work, we describe the occurrence of this sequence, as well the C-banding and karyotype composition, in populations of the group Astyanax fasciatus from Mogi-Guaçu (Araras-SP), Paranapanema (Angatuba and Pilar do Sul-SP), Ribeira de Iguape (Sete Barras-SP) and Tietê (Indaiatuba and Salesópolis-SP) river basins. The specimens from Sete Barras (10 M + 20SM + 12ST + 6A) and Araras (8 M + 22SM + 12ST + 6A) have 2n = 48 chromosomes. The samples from Angatuba, Pilar do Sul and Indaiatuba presented 2n = 46 chromosomes (12 M + 20SM + 10ST + 4A). The individuals collected in Salesópolis showed three cytotypes, bearing 2n = 46 (12 M + 20SM + 10ST + 4A), 2n = 48 (8 M + 22SM + 12ST + 6A) and 2n = 50 (8 M + 16SM + 14ST + 12A). C-banding revealed large heterochromatic blocks at terminal chromosomal regions in all populations and/or cytotypes. All analyzed populations have conspicuous blocks carrying the As-51 satellite DNA, although the number of chromosomes bearing this repetitive sequence was variable among them. Such differences were not related to the diploid number of individuals, but rather to a biogeographic pattern. Aspects of the karyotype evolution and distribution of this sequence in distinct populations are discussed

Gene mapping of 18S and 5S rDNA genes in the karyotype of the three-spot gourami Trichogaster trichopterus (Perciformes, Osphronemidae)

Ornamental fish culture is important as an economic activity and for biodiversity conservation as well. The species of the genus Trichogaster (Perciformes, Osphronemidae), popularly known as three-spot gourami, are among the several commercial species raised around the world. In the present work, eight specimens of Thrichogaster trichopterus from aquarium trade facilities were analyzed. The karyotype was composed of 23 pairs of subtelo/acrocentric chromosomes. Fluorescent in situ hybridization allowed identifying the 18S ribosomal gene at telomeric region on long arms of the largest acrocentric pair. On the other hand, the 5S rRNA gene is located at a proximal region on a pair of medium-sized chromosomes. Such information is extremely useful in face of the risks of introduction and the development of ornamental fish trade, once many fish species can be identified only by genetic studies

Studies in two allopatric populations of Hypostomus affinis (Steindachner, 1877): the role of mapping the ribosomal genes to understand the chromosome evolution of the group

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Studies in two allopatric populations of Hypostomus affinis (Steindachner, 1877): the role of mapping the ribosomal genes to understand the chromosome evolution of the group

Several cytogenetic markers show chromosomal diversity in the fish such as "armoured catfish". Although studies have characterized many species in the major genera representing these Siluridae, particularly in the genus Hypostomus Lacépède, 1803, trends in chromosome evolution of this group remain unclear. The Paraíba do Sul river basin contains the armoured catfish Hypostomus affinis Steindachner, 1877, which is unique because of its distribution of repetitive DNAs, the 5S and 18S rDNA. Identified samples and registered collections in Brazilian museums were identified as the same typological species, while we observed wide variations in the physical location of this gene in the karyotype based on fluorescent in situ hybridization results. In this study, we propose that these species can represent evolutionarily independent units, as these fish frequently undergo processes such as dispersion and vicariance and that the rDNA is associated with DNA that spreads in the genome, such as transposons. Additionally, the absence of gene flow due to the distance of the sample location could intensify evolutionary processes. The phenotypes found for the 18S rDNA showed minor changes in relation to the number of sites between the lower and upper drainage regions of Paraíba do Sul. The large difference in the number of sites found for the 5S rDNA entered the same region (upper drainage of the basin) and the literature data could represent a population dynamics where an expansion of the 5S rDNA sites provides an extinct or non-sampled cytotype in this work