1, learn the new word 10.
2. Read the text silently, understand the main content of the text and learn how to explain it.
3. Love nature and enhance environmental awareness.
Teaching focus:
1, understand the main content of the text and learn the explanation method.
2. Understand the composition of the ecological pyramid and its close relationship with human survival.
Teaching difficulties:
Educate students to love nature and enhance their awareness of environmental protection.
Teaching preparation:
1, a multimedia courseware
2. Students preview before class and collect information about the ecological pyramid.
Teaching time:
2 class hours
first kind
First, create a situation to stimulate the introduction of interest
1, multimedia broadcast a short film about the ecological environment; What did the students see? Tell me how you feel.
2. The teacher's camera passion introduction:
On the vast Yuan Ye in Africa, antelopes are running, lions are cruising and goshawks are hovering. Although their lifestyles are different, they can survive on this grassland for thousands of years. Why? Let's find the answer in the text to be studied today.
3. Write on the blackboard and read the topic together.
Second, questioning self-study.
1, query: What do you want to know after reading the topic?
Students may ask: What is an ecological pyramid? How is the ecological pyramid formed?
2. With questions, students can read the text freely, read the correct pronunciation and read the text.
Try to segment the article and summarize the main idea of the paragraph.
4. Students talk about the situation in groups.
Third, learn to appreciate and understand the content of the text.
1, read the natural paragraphs of the text by yourself 1, 2, see what you can understand and what you can't understand, and sketch in the book while reading.
2. Feedback communication. Read aloud repeatedly, taste related sentences, connect with the context and understand interesting biological phenomena.
1) The last two sentences of paragraph 1 introduce the general laws of the biological world. (? Isn't it? Or? Less quilts? These words should be combined with specific language environment to help students understand)
2) Guide students to read these two sentences well, and on the basis of familiarity, help students understand their meanings by writing on the blackboard or drawing schematic diagrams.
3. Is this really the case in biology? Read the second paragraph freely and see how the author illustrates it with examples.
4, exchange feedback, read the schematic diagram, deepen understanding.
1) The first four sentences of the second paragraph give examples to illustrate the number of organisms at all levels.
Weeds outnumber and feed herbivores.
There are more herbivores than carnivores.
2) Learn the author's explanation methods. On the basis of reading, guide students to compare and distinguish.
? A beetle 1 m2 underground foraging space can meet its energy and nutrition needs, while an eagle needs to forage within dozens of square kilometers to get enough food. ?
This sentence? Beetle? And then what? Eagle? Compare feeding space and range of activities with? 1 m2? And then what? Dozens of square kilometers? These accurate data are used to illustrate the difference between herbivores and carnivores.
3) Drawing comprehension
hawk
tit
Spider; Spider-like objects; Star wheel; Cross; Connecting handle; crosshead
Insect beetle
Cao Qing
4) Read the text to deepen understanding.
Fourth, classroom exercises.
Read the text aloud
Second lesson
First, review the previous content and import it into the following.
Last class, we studied paragraphs 1 and 2 of the text, and we knew the interdependence between organisms. So who will use their own words to say what is the interdependence between organisms?
Students can answer and express freely.
Scientists have investigated the interdependence between living things and named this interdependence? Ecological pyramid? .
Read the natural paragraphs of Text 3-6 freely and think:
How is the text introduced to us? Ecological pyramid? what's up
Second, learn to appreciate and understand the content of the text.
Students communicate on the basis of reading aloud and group discussion.
For example 1, tell us what it is. Ecological pyramid?
1) Read the third paragraph together.
2) Why is it called? ecological pyramid
(1) Review the pictures drawn in the interdependence between organisms in the second paragraph.
(2) Grasp the sentences in the text? Like a pyramid with a big bottom and a small top? To understand
3) Read again.
2. The pyramids in Egypt are made of huge stones, so? Ecological pyramid? How is it constituted?
Read the fourth paragraph, in your own words? Ecological pyramid? The composition of.
Students say and complete the structure diagram.
Meat 3 rd yingyangji
animal
The second trophic level of herbivores
The first trophic level of green plants
? Ecological pyramid? What is the relationship between different trophic levels?
Students find the relevant sentences and show them:
? In the trophic level sequence of the pyramid, the previous trophic level always depends on the energy of the next trophic level; But the energy of the next trophic level can only meet the needs of a few consumers in the previous trophic level. ?
(emphasis:? Dependence? It means that all things or phenomena are interdependent and inseparable. )
What can we see from here?
Students answer: What is the relationship between trophic level sequences? Producers at the bottom, consumers at the top? .
The teacher concluded: Yes? Ecological pyramid? The middle and lower levels are producers, while the upper level is consumers. However, the energy of the lower nutrition level cannot meet the needs of all consumers at the upper nutrition level, and can only serve a few consumers. So? Ecological pyramid? Strict level.
So you think, in? Ecological pyramid? Which level is the most important? Why?
Students find the answers to sentences from the text and talk about their experiences.
? Green plants are the energy base of all living things, the primary producers and the first nutritional level in the food chain. ?
? Green plants on the earth are collectors of solar energy and providers of energy and nutrition on the earth. ?
In other words, all living things get energy and nutrition from green plants. )
? The utilization efficiency of solar energy by green plants and their production scale determine how much energy enters the ecosystem, and also determine how many herbivores and carnivores our planet can carry, even the people at the top of the ecological pyramid. ?
(note:? Bearing? Is to hold an object and bear its weight. )
In other words, green plants also affect people. )
The teacher concluded that the number of green plants determines the bearing capacity of the earth and affects the survival of all living things on the earth.
Man is also a member of nature. What is the level of mankind in the ecological pyramid? (Top level)
Please read paragraphs 5 and 6 freely and think: What is the relationship between human beings and green plants? What method is used to explain the problem?
Students discuss and communicate after reading.
1)? Every time the ecological pyramid passes through a trophic level, the energy loss is about 90%. The higher, the finer the energy flow, the less energy flowing into the top of the tower, and the less energy that humans can use. ?
(Note: Four? Yue? Words play an important role. )
(That is to say, the energy available to human beings is limited. )
2)? Ecologist Odem made a hypothesis: in a country where meat is the main food, a boy weighing 48kg eats veal and needs to eat 45 calves a year. In order to raise these 45 calves, it is necessary to reclaim 4 hectares of land and plant alfalfa to produce feed. What is the final result? The baby weighs 48kg, the calf weighs 1035kg, and the alfalfa weighs 82 1 1kg. The weight of calves is 22 times that of children, and that of alfalfa is 17 1 times that of children! ?
It can be seen that human consumption is the biggest. Imagine: there are 6.3 billion people on the earth who need to survive, how many green plants and how much land they need! (193 countries and regions with a population of 6.3 billion)
3) Experience the interpretation method used by the author.
(The author adopts the methods of list, example and comparison. To illustrate? Ecological pyramid? Relationship with human beings)
Students find out the relevant sentences and read them.
4、? Ecological pyramid? Has a close relationship with human beings. What are you going to say?
Students talk about their feelings according to the information they have collected (it can be to introduce the information they have collected, how they feel after learning the text, or what they plan to do in the future).
5. Teacher's summary: This article introduces us? Ecological pyramid? The composition tells us that protecting green plants, cultivated land and ecological environment is to protect human beings!
As the last paragraph says:? Human activities must follow this natural law, otherwise, human beings will be punished by nature. ?
Let's read the last paragraph of nature with emotion!
Third, expand the practice.
1, select an aspect of the text, draw an ecological pyramid, and write down the contents of each layer.
2. Write a summary based on the information collected by yourself.
3. Try some explanation methods used in the article and write an article that you are familiar with.