Comparative determination of middle school students' cognitive structures related to biological diversity

The purpose of this research is to reveal the cognitive structures of middle school students (5th, 6th, 7th, and 8th grades) on biological diversity and to determine the process of change in their conceptual meaning levels by grade level. This is a qualitative research. It uses the developmental research design, which is a descriptive research method and a qualitative research design. The research sample of consists of a total of 308 5th-, 6th-, 7th-, and 8th-grade middle school students studying in Turkey's Bursa province in the spring semester of the 2017-2018 academic year. Word association tests were used for data collection. Seven key concepts were used in the word association tests: "ecosystem, biological diversity, food chain, species, endangered creatures, environmental problems, environmental protection". In the data analysis process, concept networks were created by the cut-off point technique using the frequency table, thereby making a comparison of the middle school students' cognitive structures for the related concepts. Findings were interpreted based on the results obtained from the concept networks. As a result, it was found that the middle school students (5th, 6th, 7th, and 8th grades) correctly associated the key concepts of endangered creatures, environmental problems, and environmental protection. In addition, it was determined that the 8th grade students correctly associated the key concepts of food chain, species, and ecosystem in general, while the 5th grade students correctly associated the key concept of biological diversity in general, and that the 6th and 7th grade students could not fully understand the key concepts of food chain, species, biological diversity and ecosystem. The key concepts that the middle school students associated in the word association test most were endangered creatures, environmental problems, and environmental protection. The least associated key concepts were found to be food chain, species, biological diversity, and ecosystem. The concepts the students used most were animal, plant, human, fruit, food/nutrient, environmental pollution, water pollution, pollution, global warming, garbage, filter, tree, and cleanliness. In the word association test used as a data collection tool, the students were also asked to make sentences about each key concept. Those sentences were examined and classified in terms of the information and meaning they contained, and the analysis of the sentences was performed. Based on the obtained results, it was revealed that the middle school students (5th, 6th, 7th, and 8th grades) made the biggest number of meaningful sentences about the key concepts of endangered creatures, environmental problems, and environmental protection. The study concluded that as the knowledge, experience, and awareness gained through the educational process increased, the students gave answers closer to scientific knowledge, along with the information they obtained from media such as television, press, and the internet. Furthermore, it was concluded that as the number of learning outcomes related to the concept of biological diversity in the science curriculum increased, the students' levels of knowledge and skill rose as well.