Most of the difficulties are abstract knowledge points and too complicated knowledge in textbooks.
Therefore, to break through the difficulties, we must turn abstraction into concreteness and complexity into conciseness.
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When a student's ability can't understand a knowledge point,
The knowledge point is
Students' learning difficulties.
Junior high school students are in the process of transforming concrete thinking in images into abstract thinking.
In the transitional stage of dimension, the ability of abstract thinking is poor; Junior high school students have little knowledge accumulation.
Without the knowledge accumulation of basic disciplines such as physics and chemistry,
So the cognitive level
Poor; There are a large number of abstract and obscure students in junior high school biology textbooks.
Biological concepts, principles, laws, methods and other biological knowledge; Junior high school biology education department
There are also a large number of concepts and concepts related to basic disciplines such as physics and chemistry.
Theory, such as organic matter, inorganic matter, energy, air pressure, concentration and other concepts; hydrogen
Sodium oxide can absorb carbon dioxide and other principles. So, it's all in junior high school textbooks.
A large number of knowledge points have become difficult for students to learn.
Direct indoctrination or avoidance.
These biological knowledge is not only not conducive to their understanding and application of knowledge, but also
And it will also dampen their enthusiasm for learning biology.
Reduce their research on biology
Their interest may even lead to their aversion to biology. Therefore, junior high school biology
Learning and teaching must break through difficulties.
Most of the difficulties are abstract knowledge points in textbooks.
However, the knowledge points are too complicated, so the breakthrough of difficulties must be changed from abstract to concrete.
Simplify the complex.
1
Guide students to understand the micro-world with experiments.
Biology, the standard experimental textbook of compulsory education curriculum published by Jinan Publishing House.
(hereinafter referred to as "textbooks")
)
The nucleus contains genetic material, which can be transmitted.
Genetic information.
"genetic material"
、
"Genetic information"
、
"Genetic material can pass.
Transferring gene information is abstract compared with junior high school students and requires tools.
Physics examples make students feel. It can be explained that "the nucleus contains genetic material, but
Material transmission can transmit genetic information. "
Specific examples are several classical nuclei.
Transplantation experiment. Textbook section
22
Thinking and Practice Page 1
four
Title picture "Cloned sheep"
Dolly's cultivation process "
It is a classic and intuitive experimental diagram of nuclear transplantation.
Solution.
Let junior high school students directly answer "What does the cultivation process of Dolly the cloned sheep show?"
More difficult; Teachers can turn this problem into several specific, concise and learned questions.
Small problems that students can solve guide students to feel.
Problem-oriented:
Read the textbook number.
22
Thinking and Practice Page 1
four
Title picture "Dolly the Cloned Sheep"
Cultivation process "
, and answer the following questions according to the pictures:
1
The Formation and Development of Dolly the Cloned Sheep
Which sheep are related?
2
, ewe
A
What did you give Dolly?
three
, ewe
B
What did you give Dolly?
four
, ewe
C
What did you give Dolly?
five
Which ewe does Dolly look like best? What does it offer Dolly? this
Which structure of the cell must the substance that determines the length be located?
six
Guess, Dolly looks like that ewe except for her appearance. Their athletic ability will be
Is it similar? Will the gender be the same?
By thinking and answering the above questions, students will realize that the decision of appearance,
The substance of sex and athletic ability is in the nucleus, which is called heredity.
Quality; Looks, gender, athletic ability and so on are all called genetic information. Such an abstract question
The questions will be specific, and the questions that students don't understand will be understood.
At the same time, because the relative gradient of the problem is small and easy to solve, it can be enhanced.
Students' self-confidence in learning.
Another example is that,
Textbooks:
Cell walls have protective and supportive effects.
The role of cells.
The cell wall is located on the cell surface and has a protective effect on the cell.
Acceptance, and "the cell wall has the function of supporting cells"
It is hard for students to imagine. can
Typical examples of cell walls supporting cells are as follows.
"Plant cells
Will not burst because of water absorption, but animal cells will burst because of water absorption. "
. Students are at
When doing experiments to observe animal and plant cells, there is often a question: "Why do you put onion scales and leaves?"
Putting epidermis into clear water to make temporary tablets,
Transplanting human oral epithelium into physiology
The doubt that salt water is used as a temporary pill needs to be answered. Teachers can be conscious.
Let the students explore what it would be like to put human oral epithelium into the Qing Dynasty to make temporary pills.
Result how
,
And take this opportunity to discuss the function of cell wall.
Problem-oriented:
1.
Put human oral epithelium into clean water to make temporary tablets. What will you observe?
Yao phenomenon
2.
Putting the epidermis of onion scale leaves into clear water to make temporary tablets,
What will you observe?
3.
What are the structures of animal cells and plant cells?
The difference? Think about it, why do animal cells absorb water and swell in clean water, but also plant them?
Will biological cells burst without absorbing water in clean water?
Through the above research, students will realize that the reason why plant cells burst without water absorption lies in.
Because there is a cell wall outside the cell membrane, we realize that "the cell wall has fine support."
The role of cells "
; At the same time, students will learn a little about exploring by experiments.
The method of micro-world.