Getting critical thinking about ecosystem: How impact and responses of students about the CirGi learning model?

Article history Received: 15 February 2020 Revised: 18 April 2020 Accepted: 28 April 2020 The broad scope of biology and the many sources of biology reading requires eleven grade students to think critically about sorting out information to develop and support students' critical thinking skills. CirGi is an integration of the cooperative integrated reading and composition (CIRC) learning model and guided inquiry (GI) that emphasizes reading and writing activities, accompanied by guidance from the teacher. This study aimed to analyze the influence of CirGi's learning model on students' critical thinking skills. This research uses a quasi-experiment method with prepost control group design. The sampling technique used purposive sampling, namely 104 high school students. Data collection was carried out using instruments of critical thinking skills in the form of essays, questionnaire responses of students to learning, and observation sheets of syntax implementation. The data analysis technique used was oneway ANCOVA. After controlling for the pretest scores, the CirGi learning model's influence on students' critical thinking skills was influenced. This learning model was appropriate for learning biology, so it can regrow the activities of reading science books that impact students' critical thinking skills.


INTRODUCTION
Students in eleven grade study the ecosystem at the secondary school level. The teaching of ecosystem material requires high analytical skills, and practice or application expected in daily life (Musyaddad & Suyanto, 2019;Komala, Suryanda, & Lismana, 2016). Ecosystem education discusses the relationship between organism and environment. Waiting for content from the teacher is not sufficient to achieve ecosystem learning objectives optimally. Therefore, resurrect reading activity is essential to have a more meaningful discussion process. Reading is not the best way to learn science (Robertson, 2013;Ristanto et al., 2018b). Science learning activity should involve students' investigation process to find and develop a science concept (Ristanto et al., 2018a;Noviyanti et al., 2019).
In addition to CIRC, an active learning model proven to be effective in Biology learning is guided inquiry (GI). GI learning model gives more emphasis on students to find a concept or information from various sources or teacher (Wartono, Hudha, & Batlolona, 2018;Mulyana, Rusdi, & Sigit, 2018;Siregar et al., 2019). It is believed to help students to be more active in learning Biology. The biology teacher plays a role in determining problems and directing students' ideas to achieve learning objectives (Ristanto et al., 2017). Biology teachers can also empower students' critical thinking skills by giving questions or problems that challenge students to think critically (Wartono, Hudha, & Batlolona, 2017;Kurniawati et al., 2014). A functional biology teacher should teach good thinking and a good sample or model to understand concepts learned (Tishman & Perkins, 1993;Dilekli & Tezci, 2020). The CIRC and GI learning models have good potential for Biology learning. The integration of CIRC and GI (CirGI) is expected to support and complement one another and optimizes students' critical thinking skills.
CirGi learning is developed by Ristanto et al. (2019) for Biological education. Various studies have proven a significant influence of CIRC learning model implementation in Biology teaching (Ristanto et al., 2018). There is no study, however, that integrates CirGI and aims to find out its effect on critical thinking skills in ecosystem concepts as well as to learn senior high school students' responses. This research aimed to analyze the influence of the CirGI learning model and students' response to CirGI learning in ecosystem concepts.

Research Design
The research uses quantitative research with a descriptive approach that was designed using a quasi-experiment research method (Sugiono, 2012). The research design used the Pretest-posttest control group design.

Population and Sample
The research population is 105 eleven-grade students of a private senior high school in Depok, Indonesia of the academic year of 2018-2019. The sampling technique used Yamane (1967) formula with a precision level of 1%. Based on formula calculation, 104 students obtained as the research sample. By using a purposive sampling technique, 52 students were selected to be in an experimental class taught using the CirGI learning model, and 52 other students were control class taught using conventional learning. The grouping was based on a balanced academic grade between the classes (Table 2).

Instrument
Instrument test was conducted using construct and content validity tests with an average of 81.03. The value indicated that instruments were fit to be used. Empirical validation test of instrument items used Pearson Product Moment formula. rcount was higher than rtable in a minimum range of 0.325 showed that of 15 questions tested, there were 10 valid questions. Furthermore, the reliability test measured using Alpha Cronbach obtained a value of 0.855 meant that the instruments were reliable. Instruments to measure critical thinking skills were essay tests with indicators referring to Facione (1999) as presented in Table 3.

Table 3
Critical thinking skill indicators in ecosystem concept.

Indicator Description Number of questions Sample of Question
Interpretation Understand and group various data, procedures or criteria 1 The interdependence relationship always exists in nature both between organism and between organism and its environment. One of the relationships is a predator-prey relationship known as a food chain. Pay attention to the organism interaction below! A B An ecosystem is composed of interacting components. Explain the interaction pattern between components occurred in Figure A and B! Self-regulation One's awareness in monitoring his/her cognition process, selfimprovement in applying skills 2 Global warming has been a world problem. One of its impacts is the melting of arctic ice in the north and south poles that causes an increase in sea level. As a consequence, many lands on earth are inundated. What efforts could be made to reduce the impact of global warming?

Procedures
Before ecosystem learning was conducted, students in the experimental and control classes were given a pretest to measure their initial ability. The experimental class then was taught by using the CirGi learning model in the first, second, and third meetings in September 2019. The application steps refer to Ristanto et al. (2018), as indicated in Figure 1. Control class, on the other hand, was taught by using conventional learning, which was teacher-centered learning. The post-test of critical thinking skills was then given to the experimental and control classes. Next, the students' responses were analyzed.

Data Analysis
Data were analyzed by using the descriptive test, analysis prerequisite test, correlation test, and hypothesis test. The descriptive test was conducted by calculating the average pretest and post-test of each indicator score of students' critical thinking skills. The data analysis prerequisite test used the normality test, which was Kolmogorov-Smirnov, whereas the homogeneity test used the Levine test. The Pearson Product Moment was used for the correlation test. The hypothesis test was done using One-Way ANCOVA assisted with SPSS 25 for windows.

RESULTS AND DISCUSSION
Based on the research result, descriptive statistics that consisted of a mean score, maximum value, and minimum value from the experimental and control classes are presented in Table 4. According to analysis, students who were taught by using the CirGi learning model had a higher score than students who were taught by using conventional learning, with a mean of 82.37. Before the implementation of CirGi in ecosystem teaching, the average achievement of the students in critical thinking skills was 51.48 (Table 5).
Based on the result of critical thinking skill scores, it can be seen that the post-test scores in all indicators experiences an increase in both classes, experimental and control. In the experimental class, the highest score was in the self-regulation indicator of 90.14, whereas the lowest score was an explanation of 75.72. After being taught by using the CirGi model, students were able to interpret, analyze, infer, evaluate, and explain ecosystem concepts in the aspects of ecosystem component, interaction in an ecosystem, type of ecosystem, energy flow, and biogeochemical cycle.  Post-tests in the conventional class increased, but in some aspects, the scores were still low, such as in analysis and explanation aspects that achieved only a score of 71% each. Due to the discussion process conducted in the control class less optimal, and it had not been able to foster students' curiosity on problems to be solved; thus, they had not been able to analyze and evaluate ecosystem concepts appropriately. Also, it was related to the non-existence of components of formulating problems and hypotheses in the student worksheet. The learning focused on the undirected discussion process between groups; hence, students were less encouraged to think critically. It could be observed during the presentation where some group members who presented chose to silent and depended on the group leader to present and answer questions from members of other groups.
Based on the increase in pretest to post-test scores, the class with CirGi implementation had higher scores. The class had a score difference of 31.01, whereas the conventional class had a score difference of 26.52. In the CirGi class, the analysis indicator was an indicator with the most significant increase, whereas the self-regulation indicator had the lowest increase ( Figure  2).  Figure 2 indicates that the CirGi class was better than the conventional class. Students with CirGi learning implementation were already more critical in responding to environmental issues in the self-regulation aspect. They, however, needed to be accustomed to the indicator of explaining content or problem in detail and critically. It is supported by data on the result of student response to the implementation of CirGi in Table 6  Agreement score in indicator of capable of developing critical thinking skills achieved 49.00 for strongly agree category and 47.00 for agree category. Therefore, 96.00 students indicated that CirGi was capable of improving students' critical thinking skills. It could also be observed in changes in students' attitudes in criticizing articles/reading materials. Ability to analyze properly made students more confident to explain and communicate the discussion results. The CirGi syntax in research was also well implemented from the first to the third meetings, with an average 94% (Figure 3).  The result of normality test calculation in Table 7 suggests that the p-value or significance of pretest and post-test in the experimental class and control class was more significant than α=0.05; thus, the critical thinking skill data were normally distributed. Based on Table 8, the calculation result obtained a significance of 0.191 > 0.05, or H0 was accepted. Therefore it could be interpreted that the average pretest and post-test in student groups taught by using the CirGi learning model and student groups taught by using the conventional learning model was homogeneous.

Table 9
Correlation of pretest and posttest scores of critical thinking skills. According to data of the experimental and control classes in Table 9, the pretest score, which is a covariate, had a significant correlation with the post-test score after treatment since the p-value or significance was smaller than α=0.05. Based on the data analysis conducted, the hypothesis test used ANCOVA with α=0.05. Table 10 indicates the calculation result of the learning model variable where p-value=0.001 < α=0.05, thus rejecting H0. After controlling the pretest scores, which meant without pretest scores, at a confidence level of 95%, there was an influence of CirGi and conventional learning model implementation on critical thinking skill post-test scores obtained by students. It suggested that post-test scores obtained by students were indeed due to the influence of implemented learning models instead of student experience or because they had previously learned the ecosystem material.
The achievement of CirGi's influence was higher than conventional learning models since CirGi syntax was more supporting the ecosystem material than conventional learning. The learning syntax in both CirGi and conventional classes had a discussion activity. In the CirGi class, the learning teacher provided a student worksheet that was suitable for the CirGi syntax model to optimize students' critical thinking skills. On the contrary, in the conventional class, students worked on tests in the student handbook; thus, it was not maximal in measuring students' critical thinking skills. It could be seen in the several critical thinking indicators that had not to achieved.
Additionally, the discussion process in the experimental class was guided by the teacher. According to Probosari (2015), teachers are a leading factor in the success of Biology learning in senior high school. Rabgay (2018) adds that teacher as a facilitator will motivate students to compete between groups; hence, each group will try to present their best result that impacts the learning achievement according to target. During the discussion, students might bring books or supporting articles or articles given by the teachers related to the material. Knowledge of the ecosystem of each group will subsequently be more vibrant, and it will guide them in sharpening their critical thinking skill to solve problems. Discussion component in student worksheet included CirGi syntax in formulating a problem, formulating a hypothesis, conducting an investigation, and developing the work.
The formulating problem stage could train critical thinking skills in the interpretation aspect since the teacher conducted a question and answer session and guided students to formulate problems related to problems to be solved. The existence of inquiry was able to trigger the students' critical thinking; thus, they became more open to new ideas, care about the result, and also the process to achieve the result. Due to problem formulation, students were guided to formulate relevant hypothesis to the problem formulation. Each group discussed and conveyed ideas to formulate a hypothesis on ecosystem-based on each member's knowledge following a guide from the teacher in determining the priority of hypothesis in the inquiry. The formulating hypothesis stage was capable of training critical thinking skills in analysis and conclusion aspects (Masitoh, 2017). Students in a group analyzed the reasons for each member before setting a hypothesis. After considering opinion and determining ideas from the group members, students collected information from various sources, such as provided articles, articles from the group members, or books related to the ecosystem, so that they were able to strengthen the hypothesis.
The stage of investigating to solve the problem was able to train students' critical thinking skills in the analysis and explanation aspects (Masitoh, 2017). The group members collected information and pieces of evidence from several kinds of literature that could answer the problems. Next, students were able to find and develop their knowledge concept and ended at the stages of analyzing, evaluating, and drawing a conclusion. Students analyzed problems thoroughly before presented them. It is in line with Erikson & Erikson (2018) that presentation is an effective and beneficial way to improve students' communication skills that impacts their critical thinking skill improvement. The teacher, along with the students, evaluated the discussion results from each group in the form of questions, validation or correction, confirmation and ended with a conclusion drawing from the discussion process. Conclusion drawing could train students' critical thinking skills in the aspect of conclusion and selfregulation. Students who think critically will have self-confidence and be able to explore the implications of the conclusion made.
In the control class, the teacher, as a facilitator, had less contribution to the learning process. She only gave direction at the beginning of a meeting and in the initial activity. It triggered students to take valuable points from the book for a presentation. The group members did not understand what they presented. Some groups were still incorrect in composing the concept to be presented. It was inaccurate since an incorrect concept had shaped in the students' memory before any correction or validation from the teacher.
The group who had a presentation was unable to answer questions from other groups. It indicated that the discussion was not well managed, especially in the planning stage that caused the implementation stage did not run well; thus, it affected the achievement of learning targets. According to Gupta & Ahuja (2014) and Espey (2017), the teacher as a facilitator is critical in encouraging students to initiate discussion and to ask questions for clarification. Also, Jarmita (2012) states that teachers in a group discussion must assist students in finding an answer with their mindset. The importance of developing students' thinking process is also consistent with Vanicheva (2015) that critical thinking in science is essential since each data from the scientific facts are continued to be updated, and the update requires critical thinking process.

CONCLUSION
The use of the CirGi learning model in senior high school students of Class X could improve students' critical thinking skills in ecosystem material. After controlling the pretest scores, CirGi had a significant influence on students' critical thinking skills. Students also provided positive responses or agreement to the use of the CirGi learning model that able to improve critical thinking skills. The implementation of CirGi could direct and foster students' interest in reading science books. On the other hand, it also required much time. Therefore, it must be implemented per syntax and the pre-determined time allocation of each syntax to obtain the maximum critical thinking skills of the students.