An Investigation into the Learning of Ecological Concepts

The aim of this research; secondary, high school and university levels of the students to understand the concepts related to ecology of Bayburt in Turkey. In this study, a progressive research method was used. In this method, conceptual understanding test was used as data collection tool. Open-ended test questions were used in this study. The test consisted of 150 students, 50 were from the secondary school, 50 were from the high school and 50 from the university in Bayburt. The data obtained from the test indicate that the meanings of the ecological concept are in different categories and that this concept is not fully understood by the students at all three levels of learning. While students at secondary level relate the concepts related to ecology to their everyday use, high school and university students have more scientific definitions in their descriptions. In addition, misconceptions regarding these concepts have been identified at all levels of learning.


Introduction
Biology covers important subjects about life.Thanks to biology, people can understand the development, nutrition, heal th and environment of themselves and their family as well as many significant dev elopments in the world (Alexander, 1982;Ohlsson and Ergezen, 1997).People can know and protect the environment, understand i ts significance in human life and grow up to be healthy individuals thanks to biology education (Urey, Colak and Okur, 2009).Barr (2007) stresses that education in biology and other heal th sciences should hav e priori ty over education in other scientific areas.If individuals live in an environment in which biology and health education are not apprec iated and are not provided with necessary education in these areas, they cannot grow up and develop in a health way.
Human pressure on many elements in physical environment confronts us today as the primary reason of current environmental problems.To deal with such problems, studies in recent years focus on human factor (Alexander, 1982;Barr, 2007;Ewans et al., 2007;Toman et al., 2015).It is unavoidable that humans are at the centre of the resolution of environmental problems as an important factor in the emergence of these probl ems in the first place (Bozkurt, 2001).For that reason, we need to raise the consciousness of individuals about their responsibilities in overcoming environmental probl ems, which can be achieved with an effective environmental education (Campell, Waliczek and Zajicek, 1999;Fernandes Manzanal et al, 1999;Altin et al., 2002;Urey, Colak and Okur, 2009).
Environmental education is necessary at all levels of education starting from preschool to higher education (Darcin et al., 2006).Informing individuals about the environment and providing them with positive attitudes are the main aims of environmental education (Fernandes Manzanal et al, 1999;Uzun and Saglam, 2006;Farmer et al., 2007).Environmental education is not only a subject that needs to be learned, but also a way of thinking and behaviour (Davis, 1998).Environmental education also aims that people can understand the ecological balance and thei r role in it, form opinions as to how they can live in harmony with the environment and acquire necessary skills for active and responsible participation (Erol and Gezer, 2006).Ecology that is studied under biology is a field usually dealing with theoretical concepts.Due to the abundance of the relationships between ecological concepts, it is difficult for students to learn these concepts thoroughly.Therefore, students prefer memorizing to learning them (Ozcan, 2000), and this does not differ in diverse educational levels.
In their studies, Adeniyi (1985), Bozkurt (2001), Erol and Gezer (2006) claim that students in different levels of education have many misconceptions, which may pos e problems in the working of education system.This study aims to identify the lev el of understanding of s tudents at s econdary school, high school a nd university concerning ecological concepts.

Methodology
This study uses developmental research method as a descriptive res earch approach to determine the level of learning of ecological concepts among s tudents in different educational levels.Instead of identifying the level of development by studying on a sample for a long time to determine the level of learning of ecological concepts, the res earch consists of studies simultaneously conducted on a sample that can be equivalent of the research sample (Yi ldirim and Sims ek, 2013).In this way, the research is conducted in the shortest time by studying with the samples in different age groups instead of following the same sample to complete the study (Cepni, 2012).Considering such aspects, the study has the characteristics of a cross-sectional study using developmental research method.
The study was conducted in a secondary school, high school and university in central Bayburt.The res earch sample consists of 3 senior classes, each randomly selected from th e secondary school, high school and university.The number of participating students and their distribution by gender are presented in Table 1.

Data Collection Tools
To collect data, the study uses conceptual unders tanding test and individual interviews.The properties of the data collection tools are given below.

Conceptual Understanding Test
The tes t used in the study comprises 10 open-ended ques tions with 2 questions for each of the subjects of food chai n, food web, biomass, energy flow and greenhouse effect.To present the findings obtained from the tes t data, we used certain abbreviations whose full forms are given below.For example, TS-1 indicates "the first of the secondary school students who responded to the test".
T: Test, S: Senior secondary school student, H: Senior high school student, U: Senior university student, 1: Fi rst student , 2: Second student, 3: Third student, 4: Fourth student, 5: Fifth student In addition, we also used studies conducted by Munson (1991), Urey et al. (2011) and Bozkurt (2001) in our study.It is considered that the reliability of the test questions used in these studies is confirmed.The validity of the tes t questions was also confirmed by referring to expert opinions, relevant literature and pilot study.

Data Analysis
Below you can find information about how the data obtained from the test to determine th e students' level of understanding of the investigated concept.

Conceptual Understanding Test
This study uses the categories of understanding suggested by Abraham et al. (1992) to assess the test including openended questions.These categories and their content are given in Table 2.

Level of Understanding Evaluation Criteria Full Understanding
Answers cover all aspects of the validated response.

Partial Understanding
Answers cover one or more aspect(s) of the correct answer but not all of them.Partial Understanding with Answers show partial comprehension but they also contain misconception.

Specific Misconceptions
Answers are scientifically incorrect.

Specific Misconceptions
No Understanding Blank space, answers including statements such as "I do not know", "I do not understand".Repetition of the question, Irrelevant or unclear responses.
During the analysis, the percentage distribution of the responses given by the s tudents according to thes e categori es was determi ned and presented in tabl es.For the analysis, it was decided to group the students' respons es for the main questions bas ed on their similari ty.In addi tion, authentic respons es selected from thes e responses are directly given here to set example.
The flow diagram of the s tudy is shown in Fi gure 1.Also, the following part of the study pres ents the fi ndings obtained from the analyses comprehensively.

Findings and Discussion
In this study, conducted to determine the level of understandi ng of ecological concepts among the students in different educational levels and to indicate the conceptual change between these levels, the findings are given below.

Test Findings
The level of understanding of ecological concepts among senior secondary school, high school and university students was determi ned using the test prepared as part of the s tudy.The findings on the lev el of understanding of the students at different educational levels concerning the concepts asked in the test are presented below.

Students' Level of Understanding of the Concept of Food Chain
The first two questions in the test aims at determining the students' l evel of understanding of the concept of food chai n.According to the results, Table 3 presents the senior secondary school, high school and university students' level of understanding of the concept.In the 1 st and 2 nd questions on food chain, the students were asked about the s teps in the food chain and eating habits in thes e steps.As seen i n Table 3, the rate of students who have full understandi ng of the questions is highest in university students and least i n secondary school students.The s tudents in different educational lev els who are in the category of full understanding describe eati ng styles and eating steps in the food chain wi th similar statements.For example, a secondary school student answered that: "While a living organism consumes another living organism as food, this organism itself becomes a nutritional source for another organism.This type of chain of relationships in the nature is called food chain.The firs t step of the food chain is occupied by producers.In the second step lie the organisms that eat plants, and in the third step lie the organisms eating the organisms in the second s tep.On the other hand, there are decomposers in every step (TS-17)".
In parti al understanding category, it is found that while talking about the steps and eating styles in the food chai n, the students express some of the steps and do not explain eati ng styles clearly.Table 3 indicates that the highest educational level with the hi ghest partial understandi ng rate belongs to the university students.For exampl e, the answer of a university student is as follows: "Food chain is an order that resul ts from living organisms' getti ng the energy they need from each other" (T U-17).On the other hand, the lowes t rate in this category is seen in s econdary school students.
Just as in the specific misconception and partial understanding categories , secondary school students have the highest rate i n the misconception category.However, it is seen that this rate diminishes as the l evel of education increas es.For instance, the following response of a secondary school student is repres entative of othe r students' answers: "As the amount of energy increas es from bottom to top in food pyramid, energy need also increases from bottom to upper levels."As is seen Table 3, the rate of no understanding declines with the increase in education level.A similar f inding is also revealed in the study conducted by Ozcan (2000).While he displays this situation in his study, he claims that the science of biology is a conceptual lesson, thus, the interaction between the concepts mus t be i ntroduced to the s tudents, and stresses that the meaning of the concepts must be understood rather than memorizing.

Students' Level of Understanding of the Concept of Biomass
The thi rd and fourth questions in the tes t attempt to determine the students' lev el of understanding of the concept of biomass.Table 4 pres ents the senior secondary school, high school and university students' level of understanding concerning the concept of biomass.The third and fourth questions in the s tudy attempt to determine the students' level of unders tanding of the concept of biomass.The third question actually complements the s econd question.According to Table 4, the university students have the hi ghest rate of full unders tanding regarding thes e questions.Furthermore, the rate of full unders tanding rises as the level of education i ncreases.An exami nation of the statements of the s tudents who fully understood the questions reveals that the students predomin antly say that producers hav e greater biomass than consumers.For example, a student responds that "The biomass of living organisms diminishes rapidly from producers to consumers.Those at the bottom of the food chain need to have more biomass than those at upper levels.Currently, a significant portion of the world's biomass comes from giant trees in the rain forests.Biomass of plants is significantly higher than that of animals (T U-38)".When the answers of the students in the partial understanding category are analysed, it is seen i n Tabl e 4 that the university students hav e the highest rates.It is also found that the students in this category use correct statements, but are unable to express the ans wer qui te precisely.We can see it in the statements o f a university student: "It is the common name of all materials coming from the organisms that are living or lived recently (TU-19)".
When the questions asked to assess the understandi ng of the concept of biomass is examined, it is found that the rates of misconceptions diminish as the level of education increases.The highest rate of misconceptions is seen at s econdary school level.Misconceptions stem from wrong mental schemas in the minds of the students concerning eating styles.To put it better, we can give as example the answer of a secondary school s tudent: "Biomass increases from bottom to top in the food chain, because the number of living organisms at lower steps declines as living organisms at every step feeds on those at a lower step (TS-24)".Such a misconception is also found by Adeniyi (1985) in a study conducted on students.He states that this misconception results from the assumption of the students that living organisms at the higher levels of food chain are stronger, bigger and need more energy.In our study, we fi nd quite a lot of statements based on this justification.In the no understandi ng category, the percentage of the s tudent answers declines with increasing education levels.

Students' Level of Understanding of the Concept of Food Web
The fifth and sixth ques tions are aimed at determining the students' l evel of understanding of the concept of food web.According to the data obtained from the answers, the level of understanding of this concept among s enior s econdary school, high school and university students is given in Table 5.When the answers of the students to the fifth and sixth ques tions are analysed, it is found that the university students have higher rates of full unders tanding.For example, the following answer of a university student repres ents the current situation perfectly: "Food web is a template that indicates what feeds on what wi thin an ecological community.Food web is classified in two categories: autotrophs and heterotrophs (TU-42)".
The analysis of the statements of the students responding in the partial understanding category reveals that teachers talk about the transfer of energy in food web in a s uperficial manner.It is seen that partial understandi ng rate is the highest among the high school students (Tabl e 4).To provide a better explanation for partial understanding, we can give as example the answer of a hi gh school student: "In transition from a food level to another in the food web, food energy cannot entirely be transferred (TH-30).
As for the misconceptions category, secondary school students have the highest rates.Howev er, this rate declines as education level increases.It is found that the students in this category use the concepts of food chain and food web interchangeably.This can be seen in the statements of a secondary school student: "Food chain is the simplest version of food web (T S-27)".In addition, the secondary school students have the hi ghest rates in the no understanding category.Munson (1991) and Bozkurt (2001) also reached a similar conclusion in their studies.

Students' Level of Understanding of the Concept of Energy Flow
The students' understanding of the concept of energy flow is identified wi th the question seven and ei ght.According to the data, the secondary school, high school and university students' level of understandin g of this concept is given in Table 6.An examination of the students' answers to the seventh and ei ght questions about energy flow indicates that the university students have the highes t rate as is the case wi th the concepts of food web and biomass.Students who show full unders tanding explain energy flow in food chain in detail.For example, a university student states that "A great amount of the energy stored through food chain is used for the vital needs of that organism.Only 10% of the energy is passed from one group to another in the food chain.In other words, every living organism transfers 10% of its energy to another organism that eats it.This energy transfer in the food chain is represented in a pyramid model (TU-31)".
The hi ghest rate of partial understandi ng of the concept of energy flow is found among the university s tudents as is the case with full understanding.When the answers of the s tudents with partial understandi ng are exami ned, i t is seen that they refer to the certain properti es of the concept.For example, the statement of high school student is a representative of the situation: "This energy obtained from the Sun is a unidirectional energy flow that goes to producers, consumers and decomposers and undergoes changes in every living organism (TH-13)".
The analysis of the statements with misconceptions indicates that secondary school students hav e the highest rates in this category.When the statements involving misconceptions are examined, it is found that the students use expressions involving misconceptions based on the rmody namics law in physics.This can be clearly seen in the answer of a secondary school student: "The amount of energy does not change from bottom to top in the food pyramid, because the amount of energy remains unchanged in the nature (TS-8)".Finally, in the no understanding category, the percentages of the student answers diminish with i ncreasing education lev els.Munson (1991) and Bozkurt (2001) also reached a similar conclusion in their studies.

Students' Level of Understanding of the Concept of Greenhouse Effect
The ninth and tenth questions in the test aimed at determining the students' lev el of understanding of the concept of greenhous e effect.Table 7 presents the s enior secondary school, high school and university students' level of understanding of the concept of greenhouse effect.In the ninth and tenth questions on greenhouse effect, students seem to have misconceptions about the causes and consequences of greenhous e effect, the thinni ng of ozone lay er and acid rains.As is seen in Table 7, university students mostly have full understandi ng in these questions.Students in different educational levels in the full understanding category make similar s tatements about the factors l eading to greenhouse effect.The s tatement of a university student can be given as example: "The clouds and sky refl ect the sunlight and some gases in the atmosphere such as carbon dioxide, water vapour and methane absorb this light, keeping the Earth warm.This process is called greenhouse effect (TU-10)".When the statements of the students with partial understanding are examined, i t is found that teachers expl ain the specifics of greenhouse effect superficially.The highest rate of partial understandi ng is seen among the university students (Table 4).To better describe parti al understanding, we can gi ve as example the following answer of a high school student: "There has been an increase in the greenhouses gases in the atmos phere.The reasons for that are the use of fossil fuels, destruction of forestland due to fires and the emission of large amounts of greenhouse gases to the atmosphere (TH-33)".
In the analysis of the answers for the questions on unders tanding of the concept of greenhouse effect, i t is seen that the rates of misconceptions decline as the level of education increases.Misconception i s found most among the secondary school students and least among the university students.The misconceptions stem from wrong mental schemas in the minds of the students concerning eating styles for the caus es and consequences of greenhous e effect.To bette r describe it, we can give as example the following statement of a s econdary school student: "As resul t of greenhouse effect, earthquakes, volcanic eruptions, desertification, floods and cancer take place (T S-20)".In addition, the rates of students with 'no understanding' increase as the level of education rises, as is seen in Table 7.The highes t rate in this category belongs to the s econdary school students while the university s tudents have the lowest rate of 'no understandi ng'.The study conducted by Bahar (2000) reveals that mos t of the university students were not informed about or had misconceptions about current issues such as ozone l ayer depletion and greenhouse effect before taking the "Environmental Science" course.
Literature review on the subject of ecology Examination of Secondary School, High School and University Curricula Identifying the ecological concepts to be used in the study Determining research sample Developing a test on the level of understanding of ecological concepts Application (senior secondary school, high school and university students) Analysing and presenting the resulting data Interpretation of the findings to reach a conclusion and make recommendations

Table 1 .
Research Sample

Table 3 .
Students' level of understanding of the concept of food chain(%)

Table 4 .
Students' level of understanding of the concept of biomass (%)

Table 5 .
Students' level of understanding of the concept of food web (%)

Table 6 .
Students' level of understanding of the concept of energy flow (%)

Table 7 .
Students' level of understanding of the concept of greenhouse effect (%)