"Insect Reproduction and Development" PPT courseware

Description

"Insect Reproduction and Development" PPT courseware

Part One: Introduction of New Course

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[Tang]Li Shangyin

It's hard to say goodbye when we meet, the east wind is powerless and the flowers are withered.

The spring silkworm's silk will not be used up until it dies, and the wax torch will not dry until it turns to ashes. …

Is it true that the spring silkworm's life ends when it spins silk, as the poem says?

learning target

1. Give examples of reproductive development and developmental processes of insects.

2. Give examples of complete metamorphosis and incomplete metamorphosis.

Part 2: Reproduction and development of silkworms

Bombyx mori is an insect that everyone is very familiar with. Our country was once famous for its "sericulture and silk reeling".

The world-famous Silk Road was an important transportation route across the entire Eurasian continent in ancient times. The working people of our country have been raising silkworms for a long time. A large number of Chinese silk fabrics were transported westward to Europe through this route, hence the name.

The tiny silkworm is not only closely connected with Chinese civilization, but also promotes cultural exchanges between China and foreign countries.

Let’s take a look at what the life of a silkworm is like!

discuss

1. How many developmental stages does a silkworm go through in its life?

Like silkworms, during the process of developing from fertilized eggs to new individuals, the morphological structure and life habits of larvae and adults are very different, which is called complete metamorphosis.

2. What is the difference between the larval stage and the adult stage of silkworm?

larval stage

The body is soft and segmented, with eight pairs of legs on the chest and abdomen.

It feeds on mulberry leaves, molts four times, and spins silk and cocoons before pupating.

adult stage

It has three pairs of legs, two pairs of wings, and its body is covered with white scales.

It does not eat and can hardly fly. The male silk moth dies after mating.

3. Think about it, what other insects have development processes similar to those of silkworms?

Part Three: Reproduction and Development of Locusts

Locusts are harmful insects that feed mainly on the leaves and stems of plants, such as many crops. Locusts will migrate in groups, damaging crops over a large area and causing locust plagues.

Understanding the reproductive and developmental characteristics of locusts will help prevent and control locust plagues.

The development process of locusts goes through three stages: eggs, larvae, and adults. The larvae are similar to adults in terms of morphological structure and living habits, except that their bodies are smaller and their reproductive organs are not mature. The development process of locusts is called incomplete metamorphosis.

How to prevent and control locusts?

External environmental conditions have an important impact on locust egg laying and hatching. Locusts can be controlled through the following measures:

1. Afforestation

2. Change the environment and climate

3. Reduce suitable places for locusts to lay eggs and hatch.

Part 4: Feedback in class

1. Comparing the ontogeny of locusts and silkworms, the period that does not exist in the life history of locusts is ( )

A. Fertilized eggs B. Larvae

C.Pupa D.Adult

2. In summer, annoying mosquitoes can cause harm to people's health. What stages does a mosquito go through in its development process? ( )

A. Fertilized egg → larva → adult

B. Fertilized egg → larva → pupa → adult

C. Fertilized egg → pupa → adult

D. Fertilized egg → pupa → larva → adult

3. Beautiful butterflies are transformed from "caterpillars". The period of the "caterpillar" in the butterfly's life should be ( )

A. Fertilized eggs B. Larvae

C.Pupa D.Adult

Keywords: Jiangsu Education Edition eighth grade biology PPT courseware for the second volume free download, Reproduction and Development of Insects PPT download, .PPT format;

For more information about the "Reproduction and Development of Insects" PPT courseware, please click the Reproduction and Development of Insects ppt tab.

"Reproduction and Development of Insects" PPT:

"Reproduction and Development of Insects" PPT Part One: Class Discussion What are the common insects in our lives? Which insects are beneficial? Which insects are harmful? Reproduction and development of silkworms What benefits does silkworms have to humans? Silk can be woven into silk...

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Update Time: 2024-10-05

This template belongs to biology courseware Jiangsu Education Edition 8th Grade Biology Volume 2 industry PPT template

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