learning target
1, understand the three mysteries of lemmings, and understand the enlightenment of lemmings to human beings from multiple angles. (Teaching emphasis)
2. Understand the interpretation methods and functions adopted in this paper.
Understand the unique writing method of this article, appreciate its knowledge and interest, and learn to introduce scientific knowledge vividly. (Teaching difficulties)
4. Cultivate the spirit of scientific rationality and humanistic care, explore the endless mysteries of nature and accept the endless enlightenment of nature.
teaching process
First, the introduction of new courses.
As early as 1868, people have noticed a strange phenomenon: in the spring of this year, Wan Li was clear, and a ship full of passengers was sailing on the rippling sea. Suddenly, people found a big thing crawling in the sea far from the Norwegian coastline. It turned out that a large number of lemmings swam around in the sea, one by one from the coast to the middle reaches of the sea. When their physical strength was exhausted, they drowned in the sea and followed their lemmings on until they drowned. After that, the bodies of tens of thousands of drowned lemmings floated on the sea. Today, we will unveil the mystery of lemmings.
Second, prepare independently.
1, background information
Lemmings, a small animal and rodent living in the Arctic grassland, have amazing reproductive ability. There are still many unsolved mysteries about lemmings. For centuries. Scientists have done a lot of research on this, but there has been no progress and no effect.
2. Phonetic symbols
Comparable to (p √) provoking (x √ n) rodents (niè) cubs (zi) chaos (w?ng) reproduction (yn).
3. Explanation of words
Comparable: the degree of beauty is similar; rival
Stir-up: Borrow money from others to create trouble in an attempt to cause conflict or war.
Confused: confused because of unclear distinction, I don't know what to do.
Short-sighted: a metaphor for short-sighted.
Complementarity: complement each other and cooperate with each other.
After another wave of unrest, the person in front fell down and the person behind followed.
Unbelievable: unimaginable and incomprehensible.
Hearsay: Hearsay is a legend on the road. Generally refers to hearsay and unfounded words.
4. Read the text quickly, grasp the main idea of the content, and complete the following questions independently.
What are the three mysteries of the Arctic lemmings? What is the reason why lemmings can do this?
A: The first mystery is that the reproductive capacity is amazing, which is the highest in the animal kingdom. The second mystery is that lemmings don't reproduce like this every year. Once over-bred, they will have all kinds of strange suicidal behaviors, or stop eating, or take the initiative to provoke natural enemies, or change their coat color to attract natural enemies. The third mystery is the great migration of death, where millions of lemmings gather in a mighty team and rush to the sea and die. Lemmings are animals with strong collective ideas. They are maintaining the ecological balance and the harmonious development of nature. Maybe lemmings have this instinct.
Third, cooperative exploration.
(a) Narrative part
The writing of this kind of scientific sketch can be called "introducing scientific knowledge by using narrative framework and dialogue". What are the advantages of this writing? Please sort out the six elements mentioned in this article.
A: Benefits: I vividly and interestingly introduced "I"' s exploration of the mystery of lemmings with narrative framework and dialogue, which made readers more and more excited while reading interesting stories. Moreover, the essay has dialogue and discussion, which is convenient for the content to unfold and suitable for reading psychology. The whole story contains knowledge in the narrative, and the combination of knowledge and interest makes people both knowledgeable and interesting.
Time: one day;
Location: Eskimo village site near Barrow;
Characters: "I" and Dennis;
The cause of the incident: "I" caught a lemming;
What happened: "I" listened to Dennis talking about the mystery of lemmings;
Conclusion: Dennis expressed his thoughts on the study of lemmings and the strange behavior of lemmings.
(2) Description method
Selecting and connecting Dennis's three mysteries about lemmings is a complete exposition of lemmings' knowledge. Please judge what explanation method is used in the following sentences. What's the role?
Although (1) is a mammal, it may be one of the most prolific animals, and perhaps only bacterial division can compete with it.
A: Make a comparison; Comparing the reproductive ability of lemmings with bacterial division, it highlights the strong reproductive ability of lemmings.
(2) Because of climate, disease and the consumption of natural enemies, half of them died halfway, and there are still 820,000! Oh, my God, this is an astronomical figure!
A: List the figures; Use specific figures to highlight the number of lemmings and their rapid reproduction.
(3) Someone specially studied the migration direction of lemmings everywhere, and found that their ultimate goal was to run to the sea. For example, lemmings in Sweden and central Norway head west to the Atlantic Ocean, while lemmings in northern Norway head north to the Barents Sea.
A: For example; It shows that the ultimate goal of lemmings' migration is to run to the sea.
(3) Enlightenment
Please talk about the enlightenment brought by this article from different angles.
Example: ① The mystery of lemmings, which we humans have studied for centuries, is still incomprehensible. The enlightenment from this is that there are still many mysteries in nature that we humans can't explain, and some mysteries are very difficult to understand and need further exploration. (2) If we continue to breed uncontrollably, maybe one day we will have to follow the path of lemmings. The population problem is the number one problem in the world, which deserves our serious consideration. Everything in nature is the research object of natural science. ④ In the process of scientific research, we should constantly adjust our research methods and ways of thinking.
Text box: Introduction
Fourth, blackboard design.
Strong reproductive ability
Narrative framework-lemmings' suicide-
Death migration
The case teacher version of the course "The Mystery of Lemmings" controls the crowd.
arouse
Nature has the function of regulating balance.
Five, homework design
Besides lemmings, other animals also have some strange phenomena. According to your observation and understanding, please write a paragraph to explain the strange behavior of an animal and its reasons, and communicate in class.
A: For example, a bee's hive is made up of small hexagonal hives arranged neatly. These hives are the same size, each one is a regular hexagon, each one is surrounded by other hives, and the two hives are separated by a wax wall. The bottom of each hive consists of three identical diamonds. Some curious people measured the angles of diamonds and found that they were exactly the same as the obtuse angle and acute angle (109 and 70 respectively) calculated by modern mathematicians.
Don't underestimate this kind of house. It is not only exquisite and applicable in structure, but also can withstand greater impact than other structures. Most importantly, it completely conforms to the concept of "low-carbon family"-saving materials to the maximum extent. In other words, bees build the largest hive with the least beeswax. The hexagonal "door" is only for bees with cylindrical bodies to enter and exit, so that they will not have extra space in the hive and will not feel crowded.
Sixth, teaching reflection.
How to realize the harmonious coexistence between man and the natural environment is the main problem that people worry and think about the living environment at present. This kind of teaching plan not only guides students to understand the content of the text, but also cultivates students' scientific rational spirit and humanistic care.
Case study of classroom testing
1, add some words below.
Comparable to (p √) provoke (ti m √ o) mumble (nán) times (y m √ n)
Rodents (niè) lost (w?ng) funny (J) swollen (péng)
2. Point out the wrong words in the following words and correct them.
First, the confusion of orange and the convergence of competition (unexpectedly-competition)
B, the sense of vagrancy is almost inflated (almost-generous)
C, migration, extinction, reproduction, anxiety (mania)
D, provocation is comparable to secret-secret)
3. Point out the explanation methods used in the following sentences.
Although they are mammals, they may be one of the most fertile animals. Maybe only the bacterial division can compete with it. (for comparison)
On such a vast arctic grassland, sometimes their density can reach as many as 250 per hectare! (column number)
⑶ Some people have specially studied the migration direction of lemmings around the world and found that their ultimate goal is to run to the sea. For example, lemmings in Sweden and central Norway head west to the Atlantic Ocean, while lemmings in northern Norway head north to the Barents Sea. (for example)
4. According to the text. Please summarize the three mysteries of the Arctic lemmings.
The mystery of lemmings: a teacher's guide
(1) The replication speed is amazing.
(2) Use various methods to attract natural enemies to devour themselves, so that the total amount is basically unchanged.
(3) Run into the sea and jump into the sea to commit suicide, so that the total amount remains basically the same and keeps a balance.
5. The correct order of the following sentences is (c)
(1) Previously, scientists had discovered the magical regeneration ability of another flatworm, that is, 200 new worms were cut into 200 sections and then regenerated.
By understanding how to activate this ability of worms, scientists may one day use similar "switches" to activate regenerative ability in non-regenerative species such as humans.
German researchers have discovered why worms have strange regenerative abilities.
④ The researchers compared the differences between the "close relatives" of two kinds of worms, and analyzed their extracellular signal pathways for transmitting information between cells.
⑤ They found a molecular "switch" in this flatworm to control the information transmission between cells. If it is closed, the flatworm can grow a new head to replace the original one.
a、①④③⑤②B、②⑤④①③C、③⑤①④②D、④②①③⑤
6. Observation and collection. Besides lemmings, there are some strange phenomena in nature. Please use your spare time to collect or observe the strange behavior of an animal and think about its reasons, and then communicate in class.
Answer: For example, there is a special spider in Doquisa, Guatemala. The local aborigines named it "an expert in weaving window screens", and some people called it a colorful spider, because its silk shone red, yellow, blue and cyan in the sun. Colored spiders have high web-building skills. They spit out thick latitude and longitude lines first, and then spit out thin silk along the latitude and longitude lines, weaving a dense color net that even mosquitoes can't get in, and sealing the whole window frame tightly, which can be completed in three days. At night, a phototaxis flies to the window screen, and it crawls to catch it.