Teaching case analysis can improve the level of biology teaching in senior high school. The following is a sample essay on the case analysis of biology teaching in senior high school that I compiled for you. I hope it helps you!

A case study of biology teaching in senior high school: 1. theme

This paper expounds how to strengthen teachers' guidance on inquiry teaching under the background of new curriculum, and urge students to carry out effective inquiry learning activities in classroom teaching.

Case analysis of biology teaching in senior high school: 2. teaching method

Task-driven and guided inquiry.

Case analysis of biology teaching in senior high school: 3. The process of teaching and learning.

3. 1 Teaching Link 1: Create scenarios and introduce topics. This section aims to guide students to pay attention to the relationship between chromosomes and genes.

Teacher's question: Mendel's genes control biological characters, exist in pairs in somatic cells and are passed on to future generations through gametes, and their inheritance follows the law of gene separation and free combination. Where are the genes?

Note: Homologous chromosomes in somatic cells also exist in pairs. When gametes are formed during meiosis, paired chromosomes are divided into different gametes. So what is the relationship between genes and chromosomes?

3.2 Teaching Link 2: Use analogical reasoning to guide students to discover facts, put forward assumptions and assign tasks: complete the attempt to analyze the relationship between genes and chromosomes in the study plan.

① How many types of gametes can an AaBb genotype individual produce?

② How many types of sexual germ cells (gametes) are produced by individuals with two pairs of homologous chromosomes (1 and 2, 3 and 4) during meiosis?

③ Fill in the form

After the students completed the above tasks and evaluated them, the teacher instructed: Can you describe the relationship between genes and chromosomes in one sentence?

Student: Genes and chromosomes behave similarly.

Teacher: If you are a scientist, how do you explain the fact that genes and chromosomes are similar or parallel?

After discussion, the students reached a consensus that genes are on chromosomes.

Teacher: The above process is to compare two similar things and get a hypothesis. This method is analogical reasoning in scientific research. 1903, American geneticist Sutton used locust cells as materials to study the formation process of sperm and egg cells, and also found that the separation of alleles was very similar to the separation of homologous chromosomes in meiosis, so he put forward a hypothesis through analogical reasoning: genes are on chromosomes. The students are very excited to know that they have the thinking of scientists. Students put forward similar viewpoints to Sutton hypothesis through their own activities and experienced the joy of success.

3.3 Teaching Link 3: Using guided inquiry teaching method to guide students to analyze the experimental evidence that genes are located on chromosomes is the focus and difficulty of teaching. The process is: problem induction, inquiry guidance? Analyze reasoning and make assumptions? Design experiment (understanding hypothesis deduction)? Experimental verification? Conclusion: Genes are on chromosomes.

Teacher: Hypothesis is just a kind of reasoning, which is not equal to fact. What steps must a hypothesis go through to become a fact?

Health: the verification of the experiment.

Teacher: The Sutton hypothesis was proved by another scientist, Morgan, through a famous experiment.

Show Morgan's head and experimental materials. Drosophila.

Doubt: Why did you choose Drosophila as the experimental material? Features: Small individuals are easy to feed, fast in reproduction, with many offspring, obvious relative traits, easy to observe and count, and few chromosomes. Show the chromosome composition map of male and female Drosophila: guide students to identify the chromosome composition of female Drosophila and male Drosophila, analyze and compare the differences, and summarize the concepts of sex chromosome and autosome. Please note the difference between XY. (It is intended to emphasize that the selection of experimental materials is very important for the success of the experiment)

The teacher showed Morgan's red-eyed fruit fly hybridization experiment;

P red eye (female)? White eyes (male)

?

F 1 red eye (female male) 1237.

? selfing

F2 red eye (female) 2459 red eye (male) 10 1 1 white eye (male) 782.

Guided analysis:

(1) Which relative trait is dominant, red eye or white eye? Health: F 1 indicates that red eye is a dominant trait.

(2) Does this inheritance conform to the phenomenon of separation? After biological analysis, it is concluded that red eyes (male and female) are 3/4 and white eyes (male) 1/4, which are consistent.

(3) What phenomena can't be reasonably explained when analyzing Morgan's experiment with Mendel's method? Health: White eyes only appear in male fruit flies, which is related to gender.

(4) How to explain that white eyes only appear in male fruit flies?

Hint: According to Sutton's theory, if the gene is on the chromosome, is the gene that controls white eyes on the autosome or the sex chromosome? If it is on the sex chromosome, what are the possibilities?

Students discuss in groups: draw a hypothesis.

Student: As for sex chromosomes, the theoretical basis is that sex chromosomes are related to sex determination.

Hypothesis 1: the gene controlling white eyes is only on the Y chromosome, and there is no allele on the X.

Hypothesis 2: The genes controlling white eyes are on the X and Y chromosomes.

Hypothesis 3: The gene controlling white eyes is only on the X chromosome, and there is no allele on the Y chromosome.

Teacher: Which hypothesis is reasonable? To judge whether the hypothesis is true, we must first be able to explain the experiment. Guide the students to explain Morgan's experiment with hypothesis one, and the results are inconsistent with the facts, thus eliminating the possibility of hypothesis one. The purpose of this course is to demonstrate the following tasks for students. ) The teacher guides the students to write that if hypothesis 2 holds, the genotype of parents is XWXW (red-eyed woman) XwYw (white-eyed man). Hypothesis 3 holds, and the genotype of parents is XWXW (red-eyed woman) XwY (white-eyed man). This link paves the way for students to complete the following tasks independently. )

Homework: Write the gene map corresponding to Hypothesis 2 and Hypothesis 3 in groups on the study plan, and judge whether Hypothesis 2 and Hypothesis 3 can explain the experiment.

Students: Two students write down the corresponding gene map on the blackboard, and the rest write down the corresponding gene map on the study plan.

After writing, the teacher guides the students to comment, and the result can explain Morgan's experiment.

The teacher wondered: One of the two hypotheses must be right and the other is wrong. How to verify? Health: hybridization test: F 1 Red-eyed female Drosophila crossed with white-eyed male Drosophila.

Teacher: First, use deductive reasoning to predict the result. Homework: According to Hypothesis 2 and Hypothesis 3, please deduce the possible results of F 1 red-eyed female and white-eyed male mating offspring.

Student: Two students write the corresponding prediction results on the blackboard. The rest of the students write the corresponding prediction results on the study plan.

Teachers guide students to comment, and then summarize:

According to hypothesis 2:f 1 When red-eyed females mate with white-eyed males, red eyes and white eyes account for half of the female and male offspring.

According to hypothesis 3: When F 1 red-eyed females mate with white-eyed males, the offspring of red-eyed females and white-eyed males account for half.

The teacher showed the F 1 test results of Morgan's cross between red-eyed females and white-eyed males: half of the red-eyed females and half of the white-eyed males. Guide students to compare with the predicted results. Results The predicted results of the two hypotheses were consistent with the experimental results.

Teacher: Are these two assumptions really reasonable? In order to further test the hypothesis, Morgan designed a new experiment: the white-eyed female fly obtained from the above hybridization experiment was crossed with a purebred red-eyed male fly that was not related by blood.

Homework: According to Hypothesis 2 and Hypothesis 3, please deduce the possible results of the offspring of a white-eyed female fly crossed with a purebred red-eyed male fly.

Student: Two students write the corresponding prediction results on the blackboard. The rest of the students write the corresponding prediction results on the study plan.

Teachers guide students to comment, and then summarize:

According to hypothesis 2: When the white-eyed female flies mate with the pure red-eyed male flies, the female flies in the offspring are all red-eyed, and the male flies are also red-eyed.

According to hypothesis 3: When white-eyed females mate with purebred red-eyed males, the females in the offspring are all red-eyed and the males are all white-eyed.

The teacher showed the experimental results of mating between Morgan's white-eyed female fly and purebred red-eyed male fly: all the female fruit flies in the offspring are red-eyed, and all the male fruit flies are white-eyed. And guide students to compare with the predicted results, assuming that the predicted results of 2 are inconsistent with the experimental results. Rule out hypothesis 2. The predicted results of hypothesis 3 are completely consistent with the experimental results. Prove that hypothesis three is correct. In this way, Morgan located the genes that determine red eyes and white eyes on the X chromosome.

The teacher concluded: Morgan's fruit fly hybridization experiment provided strong experimental evidence, which confirmed Sutton's? Genes are located on chromosomes? Suppose.

3.4 Teaching Link 4: Try to explain Mendel's genetic law with research results.

Homework: Write the left gene on the right chromosome of the study plan. And complete the following thinking questions:

What is the relationship between A and A? What chromosomes are they located on? What is the relationship between a and b or b, and between a and b or b? What chromosomes are they located on?

② Why do alleles separate during gamete formation? Why do nonallelic genes combine freely?

③ Fill in the following statement: In somatic cells of heterozygotes, alleles controlling the same trait exist in pairs in _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ When meiosis forms gametes, alleles will be separated from _ _ _ _ _ _ _, and the separated genes will enter the gametes respectively and be passed on to the offspring with the gametes. This expression links chromosomes with genes, which is a supplement and perfection to separation of mendelian law. It's called. Modern interpretation of separation phenomenon? .

The segregation or combination of nonallelic genes located in _ _ _ _ _ _ does not interfere with each other; In the process of meiosis, _ _ _ _ _ _ _ _ on homologous chromosomes are separated from each other, and at the same time, non-allelic genes on _ _ _ _ _ _ are freely combined. This is a modern explanation of the law of free combination of genes.

Case analysis of biology teaching in senior high school: 4. Discuss and comment.

4. 1 This teaching case embodies the high degree of unity between the internal logic of scientific discovery and students' cognitive laws, which not only enables students to understand the relevant biological knowledge in Sutton and Morgan's scientific discovery, but also enables students to experience the scientific methods in scientific discovery.

4.2 Accurate interpretation criteria of teaching cases, guiding students to make analogical reasoning through task driving, and guiding students to understand Morgan's experiment through inquiry teaching? Hypothetical deduction? Methods, strong ability to control teaching resources. Through proper situational questioning and designing question strings, students' desire to explore is effectively stimulated and their thinking is always active. The whole teaching process pays attention to the integration of knowledge acquisition process, learning methods and thinking ability training, which embodies the teaching concept of the new biology curriculum in senior high school.

4.3 The teaching process of this section will be discovered through the teaching procedures carefully designed by teachers. Is the gene on the chromosome? Our thinking process is transformed into students' learning thinking process according to the logical process of knowledge development, and students are the main body of thinking activities in teaching. Teachers are always leaders and organizers, effectively prompting students to carry out inquiry learning activities.