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The Evidence Base for Science: Life Science
The Evidence Base for Science: Life Science

What We Know

Life science education includes the investigation of cells, organisms and living systems and their characteristics, structures and functions. It also includes interactions of living organisms with their physical environments such as cycling of matter, flow of energy and community changes over time. Life sciences in the Ohio Science Academic Content Standards include all of the biological sciences and span elementary through secondary education.

What are some common misconceptions in life science and how can they be addressed through teaching?

Wandersee, Mintzes and Novak (1994) have found that misconceptions commonly held by students often mimic the explanations offered by early scientists. Researchers have identified a number of common misconceptions in life science. For example, Ozay and Oztas (2003) found that many ninth-grade students fail to make connections between the processes of photosynthesis, plant nutrition and respiration. Further, students may believe that plants are not alive and do not reproduce (Wax & Stavy, 1989). Another common misconception is that students often limit use of the term “animal” to vertebrates (Trowbridge & Mintzes, 1988). Another study by Mintzes (1984) indicates that young students have limited ideas about function and structure in organisms; for example, many believe that blood is manufactured in the heart. Many students also hold misconceptions about meiosis and mitosis, creating difficulties as they begin to solve monohybrid or dihybrid genetics problems. One problem in addressing misconceptions is that some are found in biology textbooks (Cho, Kahle & Nordland, 1985). Teachers’ use of analogies and models in instruction also may inadvertently lead to student misconceptions.

Misconceptions often are deep-seated and resistant to change (Ozay & Oztas; Smith & Anderson, 1984). Wandersee et al. concur, stating that deeply rooted misconceptions often provide a faulty framework for learning new concepts. Sometimes students simply ignore information that does not fit into their pre-existing knowledge. At other times evidence that contradicts what a student already believes brings about cognitive conflict (Llewellyn, 2002). Ideally, the discomfort resulting from uncertainty in understanding will cause a student to reconstruct his or her framework of knowledge. When this occurs, a student begins to incorporate new information and release the misconception. Llewellyn suggests that individual writing assignments may reveal misconceptions which can then be addressed.

Concept mapping may also help the teacher identify and correct student misconceptions. Concept mapping is a procedure for helping students organize concepts into meaningfully connected, as opposed to loosely connected, entities (Novak, 1977). Concept maps depict the hierarchy as well as the relationships among concepts. A completed map represents an understanding (or any misunderstandings) of the relationships between sets of concepts and efficiently relates this understanding to others. Concept mapping has spurred a great deal of research in life science education. Generally, the research concludes that concept maps enhance meaningful learning and help students identify and correct previously held misconceptions. Stoddart, Abrams, Gasper and Canaday (2000) find that concept maps also are an effective means of assessing learning on multiple levels (Stoddart et al.) and offer a means to lead students to take ownership of their own learning (Lunsford & Herzog, 1997). (For more information on the use of concept maps, see Classroom Assessment in Science Education.)

What are the roles of investigations, experiments and laboratories in teaching and learning life science?

In life science, as well as in physical and earth and space sciences, active learning has been called scientific inquiry, investigation, experiment, laboratory and practical work. All of these terms suggest learning in which the student is actively involved in constructing his or her own understanding of a concept or phenomenon. In trying to explain the difference between active and passive learning in science, Arons (1976) coined the terms backwards science and forwards science to distinguish science as commonly taught in schools from science as done by scientists in their laboratories. In backwards science, students are introduced to a concept’s terminology first, followed by an appropriate supporting activity. Forwards science, on the other hand, is the way scientists practice science, where questions lead to investigations with terminology applied later. More recently, the National Research Council (2000) stated that laboratory experiences should allow students to “act like scientists” while solving problems.

The National Research Council (2000) concludes that laboratory activities in our schools are limited and often “cookbook” in nature. That is, students do not conduct scientific inquiry; rather, they follow a tightly prescribed set of instructions to reach a forgone conclusion. Such laboratories are illustrative rather than investigative. Discussing the research of Nachmias and Linn (1987) as well as Smith and Anderson (1984), the National Research Council cautions that without careful experimental design and thorough discussion of laboratory findings, students may become confused and discouraged. Appropriately designed laboratories, however, can:

  • Challenge students’ beliefs about the natural world and lead them to struggle with alternative ideas until they are able to construct the concept accurately.

  • Help students generate knowledge directly from natural phenomena.

  • Produce lasting memory and, if followed by discussion, can lead to deep understanding of the phenomena investigated.

  • Help students learn about precision and accuracy in observing, record keeping, measuring, and inferring.

  • Involve students in solving problems (National Research Council, 2000).

Allen and Stroup (1993) indicate students should discover through repeated experimentation (i.e., replication) that there is seldom one definite answer from a scientific investigation. Another outcome of laboratories or experiments is the discovery of anomalies. According to Echevarria (2003), anomalous events, such as the birth of a white-eyed fruit fly offspring to red-eyed parents, generate new explanations and ideas that must be incorporated into the learner’s existing knowledge. This is very similar to the process scientists engage in when confronted with new information. When presented with an anomaly, life science students are more likely to experience conceptual change if the information is both intelligible and plausible.

Strage and Bol (1996) suggest increasing the amount of time allocated for active experimentation in life science as a way to increase participation by students who are poorly motivated. They caution that often teachers use teacher-centered instructional techniques and assign seat work to unmotivated students, while more motivated students perform lab activities and are given assessments involving problem-solving. In an investigation of high school biology students, Von Secker and Lissitz (1999) found that an emphasis on laboratory inquiry experiences was associated with higher and more equitable science achievement. (For more information on issues of equity, see Equity in Science Education).

Von Secker and Lissitz analyzed over 2000 tenth-grade student responses (representing 163 schools) from the 1990 High School Effect Study. The data were collected as part of the second wave of the National Education Longitudinal Study (National Research Council, 1990) of the U.S. Department of Education. A questionnaire asked teachers (most of whom taught biology) to identify which composite best described their instruction: first, teacher-directed or the extent to which they used teacher-centered instruction (lecture, demonstrations, etc.); second, critical thinking or emphasis on “habits of mind” associated with scientific literacy, such as understanding and application of knowledge, ideas and scientific inquiry processes as well as emphasis on scientific writing; and, third, laboratory emphasis or how often teachers provided experiences for students to engage actively in scientific inquiry. The influence of instructional practices on student achievement was estimated across different schools. Von Secker and Lissitz found that “Teacher-centered instruction is negatively associated with achievement...on the other hand, mean science achievement is expected to increase with the amount of emphasis on laboratory inquiry.” Further, they found that “emphasizing laboratory inquiry had a small equity effect,” while “emphasis on critical thinking was associated with a magnification of gender and minority gaps.” They concluded that “De-emphasizing traditional, teacher-centered instruction is expected to increase average science achievement and minimize gaps in achievement between individuals of different socioeconomic status.” (For more information on issues of equity, see Equity in Science Education.)

What are the roles of scientific inquiry and critical thinking in life science education?

Scientific inquiry and critical thinking are two ways of describing how students learn and process knowledge. Scientific inquiry may be active and done in a field or laboratory setting, but it also may involve reading, posing questions and reflecting. Rodger Bybee (2002) recommends that teachers help students become critical scientific thinkers by teaching life science through inquiry. Through scientific inquiry, students learn the intricacies of investigation including experimental design, data collection, data interpretation and explanation, and defense of results. Germann (1991) also stresses that teaching science through inquiry is essential to fostering in students the ability to solve problems in a manner exemplified by scientists. Scientific inquiry enables students to discover that answering one question often leads to the development of new questions. (For more information on teaching science through inquiry, see Scientific Inquiry.)

An integral component of all learning is critical thinking, making connections between new information and pre-existing knowledge and experiences. Allen and Stroup suggest that helping students to consider, reason and distinguish valid evidence from beliefs aids in developing critical thinking. Wright and Govindarajan (1992) concur that encouraging critical thinking and providing students the freedom to express ideas and decisions are important in life science education. Their research suggests that the development of new ideas is a continual process in which information taken from one study or observation leads to new questions and deeper understandings. As students mature, they also will recognize the difference between observations and deductions that arise from observations. Wright and Govindarajan recommend that students be taught to solve real-world problems and be given opportunities to practice problem-solving in life science.

 
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