(A) Overview of the design concept
Biological variation is the continuation of biological inheritance. The stability and continuity of genetic material determine the heredity of organisms, while the variability of genetic material enables organisms to mutate, and the changes in biological characteristics caused by changes in genetic material can be passed on to future generations. In particular, it is pointed out that biological traits are not only controlled by genes, but also influenced by the environment, so that students can have a more comprehensive understanding of the relationship between traits and genes and genetic variation, and lay a foundation for studying the evolution of organisms in the future.
This section is divided into two parts. In the first part, students need to master the universality of biological variation and the factors that cause it. The purpose of exploring the difference of peanut fruit size is to improve students' ability to process survey data and analyze data. To understand that "human beings cultivate new varieties by applying the principle of genetic variation", we must first make clear the difference between "heritable variation and non-heritable variation". In fact, the problem involved here is nothing more than the influence of environmental changes and genetic material changes on biological heredity. So we need to analyze more examples to understand the relationship.
Although the topic of this lesson is about variation, it must not be divorced from heredity, so we should constantly integrate the idea of heredity into the teaching process. Let students realize through learning that variation changes in the process of heredity, and heredity is transmitted in the process of variation, and the two are inseparable. Moreover, genetic variation is meaningless to living things.
(B) Teaching objectives and priorities
1. Knowledge and skill objectives:
Give examples of genetic variation and non-genetic variation, and tell the reasons for the two variations;
For example, biological characteristics are not only controlled by genetic material, but also influenced by environmental factors;
Experience the method of investigating biological variation, improve the ability of processing and analyzing survey data, and explain the survey results by using the knowledge learned;
Examples are given to illustrate several genetic breeding methods and their applications in production.
2. Process and method objectives:
Through inquiry activities, students can be trained to sample, measure, sort out data and draw curves. Students can draw the conclusion that variation is a common phenomenon through experiments.
3. Emotions, attitudes and values:
Pay attention to the influence of high technology on human society;
We can use scientific attitudes and methods to explain life phenomena.
Teaching focus
1 Take students' inquiry as the main line, and through the discussion of the inquiry results, master heritable variation and non-heritable variation, and tell the reasons for the two variations.
For example, biological character is not only controlled by genetic material, but also influenced by environment.
Several methods of genetic variation breeding and their application in production are illustrated with examples.
Teaching difficulties
1 Take students' inquiry as the main line, and through the discussion of the inquiry results, master heritable variation and non-heritable variation, and tell the reasons for the two variations.
Experience the method of investigating biological variation and improve the ability of processing survey data and analyzing data.
The corresponding new curriculum standard: the reproduction, development and inheritance of living things are the basic characteristics of life. Plants, animals and people maintain the continuation of the race through reproduction and inheritance. The basic knowledge of human reproduction, development and heredity plays an important role in students' self-awareness, healthy life and cognition of prenatal and postnatal care. Learning the basic knowledge of animal and plant reproduction, development and inheritance will help students understand the role of biotechnology in life, production and social development. Teachers should give appropriate guidance to the ethics and values involved in the above contents —— (Biology Curriculum Standard (Experimental Draft))
(3) Teaching framework
1, Introduction
2. Investigation activities
Step 3 draw a conclusion
4. Examples of other changes
5. Humans apply the principle of genetic variation to cultivate new varieties.
6. Extracurricular knowledge development
7. Class summary and practice
Teaching preparation
Teacher: Prepare multimedia courseware; Prepare materials for investigation activities
Assign study groups and tasks according to students' interests and learning conditions;
Prepare some pictures of new varieties cultivated by the principle of genetic variation.
Students: Before class, investigate the new crop products in the market and collect information about human beings cultivating new varieties by using the principle of genetic variation. Physical objects with biological variation
(five) the required teaching environment and resources, teaching materials
Teaching environment: (1) multimedia projection equipment: convenient for teachers and students to display electronic manuscripts and teaching AIDS; (2) Physical exhibition booth: it is convenient for teachers and students to display homework and physical objects.
Teaching resources: (1) Special teaching demonstration made by the teacher: showing teaching AIDS and defining learning requirements; (2) The materials that students are looking for,
Second, the teaching process
first kind
Teaching lead-in: creating scenes and introducing new lesson projections: photos of a classmate's family of three.
Find out the similarities and differences between a son and his parents.
Question: The son looks like his parents, but there are many differences. Why?
Learning activities: think and answer the questions raised by the teacher according to the contents of the slide.
Give an example of biological variation in daily life.
Teacher-student summary: Biological variation is universal.
Design intention: to stimulate students' interest in learning and attract unintentional attention. Arouse students' attention to the ubiquitous variation phenomenon and have a clear understanding of it.
Question: Let's look at the peanuts in front of us. They look very different in size. So are these variations formed by accident or because of different varieties? Is there any way to find the answer?
Learning activities: Observe and discuss the colors, shapes and sizes of the two varieties of peanuts, and have a perceptual understanding of the two varieties of peanuts.
Discuss the questions raised by the teacher and put forward the preliminary inquiry methods combined with the textbook.
Question 1. Please choose the right tool to measure the length of each peanut. Pay attention to how to measure to minimize the error.
2. Organize your data, draw a picture, find out the maximum value, the minimum value and calculate the average value.
3. Why are some big peanuts and some small peanuts, and some small peanuts are long and short? What is the reason?
Learning activities: 1. Discuss the questions raised by the teacher in groups.
2. Refer to the inquiry experiment of teaching materials and implement inquiry activities according to the inquiry scheme designed by yourself. 3. Fill in the survey activity evaluation form.
Teacher-student summary: Because any trait is the result of the interaction between the genes controlling the trait and the environment, the length of big peanuts (or small peanuts) with the same genetic composition is long or short, which is mainly caused by the environment. However, the variation caused by the environment is limited, so the fruit size of big peanuts (or small peanuts) always fluctuates within a certain range. The variation caused by the change of genetic material should be heritable, and the variation caused only by the environment without the change of genetic material cannot be inherited.
Design intention: train students to sample, measure, arrange data, draw charts, etc. Through inquiry activities, students can draw the conclusion that variation is a common phenomenon through experiments.
Second lesson
Question: The general process of guiding students to recall and explore: asking questions-making assumptions-making plans-implementing plans-drawing conclusions-expressing and communicating.
Student activity: A student takes the stage to talk about the inquiry process (physical projection).
Two groups of students report the experimental data (physical projection curve or histogram) respectively.
Design intention: While students are reporting, other groups should also listen carefully and question and evaluate the reporting group. This kind of treatment is conducive to students' mutual learning and progress. Make students learn to objectively evaluate the achievements of others and cultivate students' critical and reflective thinking. The teacher's final comments supplement the students' evaluation, which makes the whole reporting activity more complete and embodies the teacher's guiding role.
Question: Besides, what other examples of variation have you found in the vegetable market?
Student activities: Students show their collected examples of variation, including different species (animals, plants, flowers, seeds, etc.). ).
Teacher-student summary: We further realize the universality of biological variation in nature.
Design intention: let students collect relevant information, make full use of students' resources, leave more time and space for students, arouse students' enthusiasm, stimulate students' interest in learning biological science, and cultivate students' ability to collect and obtain information.
Question 1. Let's take a look at the cross breeding of wheat.
2. How did space pepper come into being?
Student activities: think and discuss the questions raised by the teacher.
Watch the video materials, clarify the cultivation methods of colored pepper and space pepper, and further understand the application of biological variation in cultivating new varieties.
The team completed the breeding process of high-yield dairy cows.
Teacher-student summary: By crossing and combining good genes, the offspring are both high-yield and lodging-resistant. Space pepper is a new variety cultivated in space, which causes genetic variation.
Design intention: The video shows the whole cultivation process of colored pepper and space pepper, which gives students an intuitive and perceptual understanding. The application of multimedia plays a very important role in breaking through the difficulties of this course. Group performance enables students to have a more intuitive understanding of the training process and externalize and apply the internalized knowledge.
Summarize the main points of this section and finish the exercises after class.
Design intention: extend learning to extracurricular activities, and don't end with the end of classroom teaching. Attachment: Table 1 Inquiry Activity Evaluation Table
Theme:
Group name
Evaluation project
score
self-assessment
Group evaluation
Teacher evaluation
suggestion
draw up a plan
(15)
1, the purpose of the activity is clear.
5 points
2. Specific activities, methods and steps
5 points
3. Clear division of tasks
5 points
Activity process
(60 points)
1. Team members actively participate and try their best to complete the task.
5 points
2, the group division of labor cooperation, willing to listen to each other's opinions.
10 point
3. There are many ways to inquire and collect information.
15 point
4. The records of collective activities are detailed and true.
15 point
5. The collected data are of high quality and complete.
15 point
fruit
(15)
1 shows rich contents and various means.
10 point
2. The on-site defense language is clear and organized.
5 points
harvest
(10)
1, can tell the experience and shortcomings of the activity.
4 points
2. Put forward suggestions for self-improvement and hope for team members.
6 points
Average total score of this group:
Total score