How does DNA make the abundant and diverged life world? To address this question, a DNA “Jigsaw Puzzle” structure model was proposed and first tested by comprehensively analyzing the genome of the model dicot plant, Arabidopsis thaliana. However, it is unknown whether this model is held in other species. Here we report the studies of the DNA structure model using the monocot plant model species, rice (Oryza sativa), and the single-celled model species, yeast (Saccharomyces cerevisiae). Analyses of the genomes sequenced so far revealed that the genome of an organism consists of a limited number of sequence-specialized, so-called fundamental function elements. For a higher organism, these elements often include genes (GEN), retro-transposable elements (RTE), DNA transposable elements (DTE), simple sequence repeats (SSR) and low complex repeats (LCR). Datasets were developed for RTE, DTE, SSR, LCR and GEN as well as genes categorized into different function categories from the sequences of the rice and yeast genomes using appropriate window sizes. The datasets were subjected to statistical analyses to test the DNA “Jigsaw Puzzle” structure model in terms of the unambiguousness, correlation, uniqueness and selection of their genome-constituting element arrays. The analyses were conducted with a series of window sizes of the sequences at both the whole genome and individual chromosome levels, both including and excluding the centromeric regions. The results showed that all fundamental function elements of the genomes as well as the genes categorized into different function categories were arrayed in the genomes in an unambiguous manner resembling linear “Jigsaw Puzzles” at the whole genome and/or individual chromosome levels, no matter whether the centromeric regions were included or excluded. The analyses revealed that arraying of the genomic elements was correlated significantly and uniquely for each chromosome and each species. This further confirmed the non-random arraying characteristic of the genomic elements for the DNA “Jigsaw Puzzle” structure model and suggested that the DNA “Jigsaw Puzzle” structure is unique for an organism, which has probably resulted from natural selection. These results unambiguously support the hypothesis of the DNA “Jigsaw Puzzle” structure model. Since the content, arraying and interaction pattern of the fundamental function elements were shown to be unique for each organism, variations of an organism in its DNA “Jigsaw Puzzle” array would lead to phenotypic variations, thus resulting in different organisms. Moreover, the fundamental function elements constituting a genome, as the four nucleotides (A, T, G and C) of DNA, could be arrayed into an infinite number of DNA molecules, thus giving different forms of organisms. Therefore, the DNA “Jigsaw Puzzle” structure model would provide a novel, but convincing explanation for the abundance, diversity and complexity of living organisms in the world.

The primary purpose of the present study is to compare the effectiveness of the jigsaw task and information gap tasks in understanding new words and retaining them. Sixteen pupils aged between eleven and twelve were involved in the study and divided into two groups. They were allocated either a jigsaw task or an information gap task. This study consists of a pre-test, immediate post-test, delayed post-test as well as a questionnaire. The pupils were required to carry out the chosen tasks, tested immediately and then one week later. The results of the questionnaire are also discussed in order to establish the pupils’ attitudes towards their allotted tasks.   The results revealed marginally higher scores in the immediate post-test for pupils performing the information gap task in terms of recognizing the meaning of words. However, this advantage disappeared when it came to the depth of vocabulary knowledge and word meaning retention. Pupils performing jigsaw task outperformed group B in productive vocabulary knowledge and their retention. The gain in vocabulary among pupils who performed the jigsaw task is most evident in the delayed post-test. This result is consistent with the pupils’ assertion that they enjoyed doing the jigsaw task more than the information gap task. To sum up, the jigsaw task best promotes pupils understanding of words and their retention.

Intermediate calculus bridges secondary school and advanced university mathematics courses. Most mathematics education research literatures indicated that the conceptual knowledge in intermediate calculus has challenged first year undergraduate mathematics and science learners to a great extent through the lecture method. The content knowledge attained by them has been tremendously decreasing. Negative attitude exhibited by students toward calculus was highly influenced by the lecture method used. Generally, students have not looked at the learning of all mathematics courses offered in universities as normal as other courses. Due to this lack of background conceptual knowledge in learners, they have been highly frustrated by the learning of advanced mathematics courses. Taking the understanding of teaching and learning challenge of conceptual knowledge of calculus into consideration, Ethiopian public universities have been encouraging instructors to devise and implement active learning methods through any professional development training opportunity. The training was aimed to enhance learners’ content knowledge and attitude towards calculus. This is one of the main reasons for the motivation of this study that experimental group learners were allowed to be nurtured by the lecture method in their mainstream class, and then also the active learning intervention method integrated with GeoGebra in the mathematics laboratory class. Only conventional lecture method was used to teach the comparison group in both the mainstream and mathematics laboratory class. The purpose of the study was to explore the Gambari and Yusuf (2016) stimulus of the jigsaw co-operative learning method combined with GeoGebra (JCLGS) on statistics and chemistry learners’ content knowledge improvement and change of their attitude towards calculus. The post-positivism mixed methods tactic was used in a non-equivalent pre- and post-test comparison group quasi-experimental design. The population of the study was the whole freshman mathematics and science degree program learners of two public universities in Ethiopia in 2017. Samples of the size 150 in both the experimental and comparison groups were drawn utilizing two-stage random sampling technique. A questionnaire using a Likert-scale on attitudes and an achievement test were sources used for data collection. Data analysis employed descriptive statistics conducting an independent samples t-test and a Two Way ANOVA for repeated measures using SPSS23. Each of the findings on content knowledge, conceptual knowledge, and procedural knowledge development produced through the TWO-Way ANOVA, respectively as F(1,148)=80.917; 𝜂2=.353; p<.01, F(1,148)=106.913; 𝜂2=.419; p<.01, and F(1,148)=7.328; 𝜂2=.047; p<.01, revealed a statistically significant difference between the treatment and comparison groups from pre-test to post-test. These findings show that the experimental group participants were highly beneficial in developing their content knowledge and conceptual knowledge through the active learning approach and technology-based learning strategy using Vygotsky’s socio-cultural learning theory. The JCLGS learning environment representing Vygotsky’s socio-cultural learning theory modestly influenced the procedural knowledge learning of the experimental group learners’. Although the lecture method affected the comparison group students’ knowledge development in calculus during the academic semester, the impact was not comparable to that of the active learning approach and technology-based learning strategy. The major reason for this was the attention and care given to the active learning intervention integrated with GeoGebra by the researcher, data collectors, and research participants. Overall findings showed that the active learning intervention allowed the experimental group students to considerably enhance their conceptual knowledge and content knowledge in calculus. Learners also positively changed their opinion towards calculus and GeoGebra. The intervention was a group interactive environment that allowed students’ to be reflective, share prior experience and knowledge, and independent learners. As a matter of fact, educators are advised to model such a combination of active learning approach and technology-based learning strategy in their classroom instructional setting and practices. Consequently, their learners will adequately benefit to understand the subject matter and positively change their opinion towards university mathematics. / Mathematics Education / Ph. D. (Mathematics, Science and Technology Education)