A. Introduction The use of concept maps as a teaching strategy was first developed by J. D. Novak of Cornell University in the early 1980's. It was derived from Ausubel's learning theory which places central emphasis on the influence of students' prior knowledge on subsequent meaningful learning. According to Ausubel, “the most important single factor influencing learning is what the learner already knows. Thus meaningful learning results when a person consciously and explicitly ties new knowledge to relevant concepts they already possess. Ausubel suggests that when meaningful learning occurs, it produces a series of changes within our entire cognitive structure, modifying existing concepts and forming new linkages between concepts. This is why meaningful learning is lasting and powerful whereas rote learning is easily forgotten and not easily applied in new learning or problem solving situations which the present science curricula so advocate. The Concept map is a device for representing the conceptual structure of a subject discipline in a two dimensional form which is analogous to a road map. A concept, as defined by Novak, is a regularity in objects or events designated by a specific label. Concept maps are diagrammatic representations which show meaningful relationships between concepts in the form of propositions. Propositions are two or more concept labels linked by words which provide information on relationships or describing connections between concepts. A concept map can be considered as somewhat similar to a spider chart, an organization chart or a flow diagram. The most useful form of a concept map for teaching and learning is one arranged in a hierarchical organization which the more general and more inclusive concepts at the top of the map and the more concrete and specific ones at the bottom. In the teaching and learning of Biology (or any science subject), concepts do not exist in isolation. Each concept depends on its relationships to many others for meaning. A concept map depicts hierarchy and relationships among concepts. It demands clarity of meaning and integration of crucial details. The concept map construction process requires one to think in multiple directions and to switch back and forth between different levels of abstraction. In attempting to identify the key and associated concepts of a particular topic or sub-topic, one will usually acquire a deeper understanding of the topic and clarification of any prior misconceptions. One big advantage of using concept maps is that it provides a visual image of the concepts under study in a tangible form which can be focused very easily. They can be readily revised any time when necessary. During the formulation process it consolidates a concrete and precise understanding of the meanings and inter-relation s of concepts. Thus it makes learning an active process, not a passive one. In presenting concepts to students, teachers should never ask students to memorize prepared concept maps. This could merely promote rote learning and so defeat the purpose of encouraging active meaningful learning on that part of the learner. B. Use of concept maps in teaching Teaching a topic In constructing concept maps, difficult concepts can be clarified and can be arranged in a systematic order. Using concept maps in teaching helps teachers to be more aware of the key concepts and relationship among them. This helps teachers to convey a clear general picture of the topics and their relationships to their students. In this way, it is less likely to miss and misinterpret any important concepts.   Reinforce understanding Using concept maps can reinforce students' understanding and learning. This enables visualization of key concepts and summarizes their relationship. Check learning and identify misconception The use of concept maps can also assist teachers in evaluating the process of teaching. They can assess the students' achievement by identifying misconception and missing concepts. Evaluation Students' achievement can be tested or examined by concept mapping. C. Steps in constructing concept maps Select Focus on a theme and then identify related key words or phrases. Rank Rank the concepts (key words) from the most abstract and inclusive to the most concrete and specific. Cluster Cluster concepts that function at similar level of abstraction and those that interrelate closely. Arrange Arrange concepts in to a diagrammatic representation. Link and add proposition Link concepts with linking lines and label each line with a proposition. Source : Curriculum guide, CDC All rights reserved.