What do children think is inside a crab on a seashore in Paraná - Southern Brazil? (Case Study)

Children from Southern Brazil have a basic knowledge of internal anatomy of the crab from their everyday life?  A total of 434 children 194 aged 5, 67 aged 10 and 173 aged 12 were asked to draw what they think is inside a Brazilian crab which lives in a mangrove swamp. A real preserved seashore crab was presented in the classroom during the class period and children were given 15 minutes to draw the drawing on a A4 sheet of blank paper.  These pupils attended 3 public and 1 private schools in an urban area 100 km away from the seashore in Curitiba town. Analysis of the collected drawings by 5 years old pupils revealed that most achieved level 2  “one or more internal organs at random”, those at 10 years old achieved level 4 “two or more internal organs in appropriate position, whereas those children 12 years old achieved level 5 mentioning a few organ systems according to the grade level rubric developed by the authors. On the whole  very few drawings depicted organ systems. This study intended to evaluate the mental model represented by the drawing which in this case is the expressed model what children think is inside the crab.  Invertebrates are a very neglected area in the curriculum of the preschool and first grades of primary school. Internal anatomy investigation of what children think is inside invertebrates is very scarce. This study has shown that children have a poor understanding of the internal organization of organs and organ systems of crabs sometimes pupils depicting human or vertebrate organs (e. g. lung instead of gills, “dog” bones) as a template for explaining their understanding. Heart and brain were the most mentioned organ both genders by all participating ages and respiratory and digestive systems the most mentioned by twelve years old pupils. Educational implications are discussed.