Step 2.The students are required to finish reading the whole text before the class and try to understand the major points of the chapter.The students are supposed to underline the difficult words or structures and raise their questions concerning any difficulties their may have in their understanding of the text,the teacher is responsible for helping them resolve the above problems. Discussion organization(ten minutes) Organize a group discussion among students to let them talk about population size regulated by density-dependent factors or by density-independent factors Part V.Assignment: Exercises: 1.Compare two types of population growth:Exponential and Logistic 2.Mechanisms of population regulation:Why are some species rare?What factors regulate population size?
Chapter 6 Ecological Genetics I.Teaching Objective: 1.Help the students to master polymorphism and ecotypes,ecotines 2.Help the studentsto L.Focal Points and Difficulties in the Chapter(教学重点和难点) 1.Focus Genotypic variation in populations may produce patterns of variation called ecotypes or ecoclines,although often the variation appears random 2.Difficulties Many populations show a series of phenotypic characters which suggest they are adapted to live in the environment where they are found.These characters usually remain even if the organisms are put in a different environment,and are inherited by their offspring.indicating that the characters are genetically rather than environmentally determined. III.Methodology Powerpoint presentation will be the main method.Blackboard will be an assistance.Some beautiful diagrams have been prepared for visualization ⅣPresentation(课堂讲解，学时分配为1学时左右) Step 1.Warm-up Activity List the main vocabulary in the chapter and explain Let the students have a understanding about the main problems discussed in the chapter. Step 2.The students are required to finish reading the whole text before the class and