Teaching plan of "biological invaders" in the second day of junior high school

"Biological Invaders" Teaching Plan 13 (Shandong Education Press, Grade 8, Volume 2)

23. Biological invaders

Teaching objectives

Knowledge target

1. Accumulate vocabulary, master the pronunciation and meaning of words such as "plunder, habitat, fencing, blame", understand the meaning of words such as "doomed, colorful, helpless, natural selection, indifference", and learn to use them.

2. Understand the knowledge of ecological environment introduced in this paper, and understand the situation of biological invaders.

capability goal

1. Make clear the explanation order of this article, grasp the content of the article as a whole, and improve the reading ability of popular science.

2. Analyze the interpretation methods used in this paper to achieve its expressive effect.

Moral education goal

Understand the biological "pollution", strengthen the awareness of prevention, and strive to build and protect our home.

Teaching focus

Make clear the interpretation order of this article and master the interpretation methods used in this article.

Teaching difficulties

Guide students to understand: how to treat "human intervention" in the process of species migration? Why are the two conditions of "not competing with similar foods" and "not being harmed by natural enemies" emphasized in the process of forming "biological invaders"?

teaching method

1. Students mainly study by themselves. Teachers design reading topics, guide students to read independently, help students grasp the content of the text as a whole, and explore the interpretation skills of the article. Teachers only give necessary guidance.

2. Discussion method. Students can ask questions freely, explore and solve problems together through various forms of discussion and cooperation.

training/teaching aid

mixed-media

Class arrangement 1 class hour

teaching process

Students read the text by themselves, make clear the author's writing ideas, and then make clear the order of the articles; Analyze the interpretation methods used in this paper, and experience its expression effect, learn to use appropriate interpretation methods to write rational interpretation articles; Link extension, transforming the knowledge learned in class.

[Teaching Steps]

First, guide the design.

Design (1)

According to Guangming Daily (June, 2000 12), Mikania micrantha, a "plant killer", is spreading rapidly in Neilingding Island on the southwest coast of Shenzhen. They are like huge nets, shrouded in the darkness of beautiful litchi trees, banana trees and acacia trees. Trees die silently because they can't get sunshine, flowers and green grass wither because they can't get fresh air, and the land on the island is becoming a wasteland. Neilingding Island, known as the "plant paradise", may be destroyed by Mikania micrantha. So why is Mikania micrantha so destructive? Let's look for the answer from the biological invaders who entered Mei Tao. ?

Design (2)

What is a "biological intruder"? You may not be familiar with this. You know, this is a war initiated by human beings without smoke, which cannot but arouse our high vigilance. Today, we will go into the battlefield and make an inspection of this "war".

Second, students read the text independently, and teachers design questions to guide students to read independently.

Multimedia display:

1. Pay attention to the bold words below.

Blame it on predatory habitat fences.

2. Judge the correct and wrong usage of the following words.

A. I heard that Xiao Lin was admitted, and she was psychologically unbalanced, and the past came to mind again.

B.it came so suddenly that she seemed helpless.

C. if the natural environment is seriously damaged, all life will be destroyed.

D. despite the teacher's repeated persuasion, she remained indifferent.

Please summarize the knowledge about biological invaders introduced in this article in your own words. (not less than 5 points)

4. Make clear the order of this article.

5. What explanation methods are used in this paper? Find out and talk about their expressive effects.

Students think independently and then communicate in groups. The teacher chooses the leaders of five groups to communicate with the whole class, and each group is responsible for a small problem.

clear:lüèq fān Jiù

2 . a√b√c√d×

It doesn't matter: I'm not moved at all, I'm not tempted at all. Repeat the previous ideogram of "heart".

3. Biological invaders refer to "immigrants" who originally lived in a foreign country and moved to a new ecological environment by unnatural means. The harm of biological invaders is enormous, causing incalculable economic losses to human beings and posing a great threat to other invasive species and species diversity. So how did these biological intruders invade? Why is it increasing? Due to the growing prosperity of international trade, biological intruders "sneak" into China by hitchhiking in transnational trade; In addition, transnational pet trade also provides convenience for "biological invaders". At present, biology and ecology have different attitudes towards biological invaders: some people think that through "natural selection", the harm of "biological invaders" can be limited and a new ecological balance can be achieved; Others believe that letting "biological invaders" develop freely will cause serious harm to local ecology and human life. Countries all over the world are taking corresponding measures against "biological invaders".

This is an explanatory article, explaining things in logical order. Starting with explaining the concept of "biological invader", this paper introduces the phenomenon of "biological invader", its harm to human beings and its destructive effect on ecological environment, discusses the reasons and finally discusses the countermeasures. Basically, it is carried out in accordance with the logical thinking of asking questions, analyzing problems and solving problems.

5. List the figures. For example, "Since World War II, nine of Guam's native 1 1 species of birds have been wiped out by brown snakes, and the number of the only two species of birds is decreasing, which is in danger of extinction at any time." The change of this figure clearly shows the harm of "biological invaders" to the natural ecology. Another example is: "In the United States alone, the economic loss caused by' biological invaders' is as high as more than 200 billion US dollars every year", which shows that' biological invaders' do great harm to human beings.

For example. Some examples are given to support this view and make it more convincing. For example, dandelion and fish and shrimp in a mountain stream with very limited breeding time and spatial span are taken as examples to prove the statement that "in the early stage of human civilization, land and navigation technologies were underdeveloped, and the ecological balance of nature was not greatly damaged"; Examples of spotted shellfish in Europe, horned beetles in Asia and red ants in South America invading North America are cited, which strongly illustrate the great harm that "biological invaders" have brought to mankind. Give an example of palm tree snake nearly killing birds in Guam to illustrate the destruction of natural ecology by "biological invaders"; Taking fresh fruits and vegetables and transnational pets as examples, this paper explains the human causes of "biological invaders"; Taking the bill passed by the US House of Representatives to strengthen the inter-departmental monitoring of vehicles that may carry alien species as an example, it shows that all countries in the world have taken corresponding measures to deal with "biological intruders".

For example. For example, the concept of "biological intruder" is metaphorical in itself, telling people that this kind of "intruder" behavior will bring harm to human beings and nature; Comparing the European bamboos that landed in North America to "stowaways", they landed on the North American continent unconsciously and quietly caused harm to human beings; The spread of pests around the world through trade routes is compared to "hitchhiking in transnational trade" These metaphors make the explanation more vivid, vivid and attractive to readers.

Third, students are free to ask questions, and students will discuss and answer each other. Teachers will organize student activities and give necessary guidance.

1. Each group takes turns to ask questions and discuss and solve them in the group. If you can't get a satisfactory answer, ask the teacher questions.

2. The teacher classifies and summarizes the questions raised by the students, and then demonstrates them, and the whole class discusses and solves them.

Questions that students find difficult to answer may include:

(1) How to understand "human intervention" in the process of species migration?

(2) Why emphasize the two conditions of "no competition from similar foods" and "no harm from natural enemies" in the process of forming "biological invaders"?

(3) Do you know other "biological invaders"? Have you ever found biological invasion in your life?

Teacher's guidance: (1) The natural reproduction and migration of biological species are very slow and limited by spatial span. But if this migration is caused by human cross-regional activities, the consequences will be unimaginable. Therefore, "human intervention" should be fully considered when preventing "biological intruders".

(2) The natural existence and development of living things have certain laws, namely "natural selection" and "survival of the fittest". The species in a certain area are all part of the local biological chain and have been in a state of balance for a long historical period. If human intervention breaks this balance, it is equivalent to breaking the balance of the biological chain, which may have two consequences: one is to reach a new balance after a long time; The other is to produce "biological invaders", which will bring harm to local ecology and human life.

(3) Teachers can use the materials at hand to introduce some examples of biological invasion:

① In China, a South American aquatic plant, Water hyacinth, greatly reduced the water area of Dianchi Lake in Kunming, and the local climate was obviously dry. There were 68 species and 38 species of fish in the lake.

② In Western Europe, a North American shrimp disease is attacking local shrimps, causing local shrimps to disappear in many rivers.

In the Mediterranean Sea and Adriatic Sea, a Pacific seaweed covers 3000 hectares of the sea floor.

④ From East Africa to the Indo-Pacific region, a A Lang grass from South Asia invaded millions of hectares of tropical forests, seriously affecting the natural regeneration of local trees.

⑤ A pathogenic fungus from Australia, possibly from Papua New Guinea, invaded from 1920, resulting in the destruction of thousands of hectares of forests. This fungus is harmful to three quarters of plants, including tall trees and short shrubs.

In New Zealand, a nocturnal kangaroo from Australia is estimated to eat 265,438+0 tons of local forest every night.

⑦ The palm tree snake from Papua New Guinea made the wild 1 1 species of birds and some lizards and bats extinct in Guam in the Pacific Ocean.

Today, February 2, 20021Daily News Report Recently, the General Administration of Quality Supervision, Inspection and Quarantine, the Ministry of Agriculture and the State Forestry Administration jointly issued an announcement to suspend the import of pineapple, banana seedlings and other parasitic plants of banana perforation nematodes from the Philippines. Once found, all will be returned or destroyed.

It seems that "biological intruders" may invade at any time today, and China has taken strict precautions against "biological intruders".

Fourth, class summary.

The Biological Intruder is an expository article, which explains things in a logical order, with clear organization and proper explanation methods. It is a normative expository article, and its writing method is worth learning from for beginners. The knowledge about biological pollution introduced in this paper should be learned to use, improve awareness of prevention, strengthen ecological awareness, understand the value of local natural scenery, and resist the invasion of foreign creatures.

Verb (abbreviation for verb) assigns homework.

1. Use the Internet to search for information about biological pollution, sort it out and tell students.

2. Read about light pollution and answer the questions.

light pollution

An environmentalist in the west once put forward an argument that human beings are destroying the world while creating it. His words are a little pessimistic, but they are also true. The exploration of coal and the development of oil have greatly promoted the development of industry. But not long after, people found that the city was shrouded in dust and fog, and the rivers were polluted by oil.

Similarly, when Edison's electric light flashed that epoch-making light for the first time, generations were immersed in cheers and thousands of sleepless cities were born. In the face of brightly lit scenes, people can't help but admire: the Milky Way in the sky fell on earth. However, when students turn on the lights to study at night, when workers burn the midnight oil, and when citizens are immersed in the sea of lights on holiday nights, have we ever thought that if it brings bright lights to mankind, it will also become a kind of pollution?

1950, when a British transport plane landed at night, it mistook the street lamp of a section of expressway for the indicator light of the airport runway, which led to the tragedy of plane crash and death.

In Chile, an old man jumped to his death because the "little sun" on the construction site outside the window could not sleep at night.

As for driving at night, there are countless traffic accidents caused by the dazzling lights of cars coming from the opposite side.

Due to the lack of scientific and rational use of lighting, lighting has become a kind of pollution, which brings great harm to human beings and cannot but attract people's attention.

There are usually two reasons for this pollution:

First, the brightness is too large, exceeding the amount needed for normal work and life. Usually, the brightness of the lamp used by people is about 80~ 120 lux. When the brightness is too high, it will hurt people's eyes, cause diseases such as myopia and blindness, and even bring mental stimulation.

Second, the distribution of light sources is unreasonable. The aforementioned night flight plane crash was caused by this.

In order to eliminate light pollution, people have taken many measures according to the causes of light pollution. For example, the regulation of the maximum brightness index of lamps in daily life is one of the measures to protect human health; In the production environment where high brightness is needed, it is also a good method to equip the operator with anti-glare glasses. The installation of dual-focus anti-glare lights on cars has greatly reduced the number of traffic accidents related to this.

Now people have a lot of understanding of the rationality of light source distribution that was previously ignored. In some countries in western Europe, the government has incorporated the provisions to prevent distributed light pollution into environmental protection laws. Arrange the distribution of light sources near hospitals, houses, hotels and other facilities reasonably, and stipulate their maximum gathering brightness according to different situations.

With the enhancement of people's awareness of environmental protection, the problem of light pollution is gradually being solved. In addition, military experts have turned waste into treasure and used light pollution as a strategic defense strategy, which has achieved certain results.

Just as the Thames turns from turbid to clear, the problem of light pollution will be completely solved. Because human beings are not only good at creating a beautiful world, but also good at protecting this beautiful world and making it more brilliant.

1. What kind of interpretation order is adopted in this paper?

2. What explanation methods are used in this paper?

Reference answer:

1. This article is an expository article, explaining things in a logical order. Through some special examples, such as transport plane crash, mental disorder of the elderly, traffic accidents caused by dazzling lights, etc., this paper expounds the causes of light pollution, and puts forward some solutions. The explanation materials are basically arranged according to the idea of asking questions-analyzing problems-solving problems.

2. The interpretation methods used are: examples and charts. Examples are the main explanation methods.

● Blackboard design

Second, organize a small debate on whether to interfere with' biological invaders'.

(Basic viewpoint: (1) Humans should not interfere too much with the migration process of biological species, and the imbalance is temporary. "Natural selection, survival of the fittest", the balance of nature will eventually be realized. (2) Human beings must intervene in "biological invaders". If left unchecked, the diversity of natural species will be seriously damaged and human society will suffer huge economic losses.