"Growth Changes of Silkworms" Animal Life Cycle PPT Courseware 2

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"Growth Changes of Silkworms" Animal Life Cycle PPT Courseware 2

Silkworm skin is gone

When the silkworm does not eat and raises its head high, it is called "sleeping".

After the silkworm "sleeps", the silkworm begins to "skin" from head to tail.

During the silkworm baby stage, a fifth-instar silkworm will shed its skin four times in total.

When silkworms grow to a certain stage, they will grow new skin and replace the old skin. This is called molting. Silkworms shed their skin because the silkworm's body needs to grow, and the epidermis limits the body's growth.

From the ant silkworm to spinning silk and cocoon, it sheds its skin four times.

The ant silkworms after ingestion are called the 1st instar silkworms, the 2nd instar silkworms after the first sleep, and so on, the 5th instar silkworms after the fourth sleep. Dormant larvae do not eat or drink. When the larvae develop to the end of the fifth instar, they gradually stop feeding, the silkworm body shrinks, the digestive tract is emptied, and the silkworm becomes transparent. At this time, it is called mature silkworm.

During the molting process, silkworms spin out a small amount of silk, fix their abdomen and legs on the silkworm seat, raise their head and chest, and stop moving as if they are asleep, which is called sleep.

Chest: consists of three links. There is a pair of thoracic legs on the ventral surface of each thoracic segment, a total of three pairs of thoracic legs.

effect:

1. Help the mouthparts control mulberry leaves to feed.

2. Used for making cocoons when spinning silk.

3. It only plays an auxiliary role in crawling.

Scientific knowledge 1

Silkworm appearance: white, cylindrical.

Head: Small, oblate, located at the front of the silkworm body.

Thorax: It is the three links behind the head. Each link has a pair of legs on its ventral surface, called thorax.

Abdomen: The ten links behind the chest. Segments 6, 7, 8, 9 and 13 each have a pair of gastropods. The gastropods on segment 13 are also called uropods because they are at the tail.

How do silkworms eat mulberry leaves?

The three pairs of legs on the chest can hold mulberry leaves to help eat, the four pairs of legs on the abdomen can move the body forward, and the last pair of tail legs on the abdomen can attach to objects with the abdominal legs to lift the front half of the body and perform various activities. .

Scientific knowledge 2

Thoraxes: Consisting of 3 segments, with dark brown claws at the lower end, which are used to hold mulberry leaves.

Gastropods: They are soft and jointless fleshy protrusions with disc-shaped tips and densely covered dark brown claws on the inner edges. Their function is to move the body forward.

The small black spots on both sides of the silkworm's body: are the valves, used for breathing.

Movement: Repeatedly move forward in waves.

Silkworms before spinning: If they don’t eat mulberry leaves, their bodies will turn yellow and shiny

Silkworm after spinning: its body becomes smaller and is hidden in the cocoon.

How to spin silk: body movement, head shaking back and forth.

What else will silkworms grow into?

After the silkworm becomes the fifth instar silkworm, what characteristics of the mature silkworm will it soon show?

After the silkworm molts four times, it becomes the fifth-instar silkworm. Generally, after five to eight days, it will show the characteristics of old age: loss of appetite, transparent chest, and then stop eating completely, the abdomen also becomes transparent, and the head of the silkworm body becomes transparent. It raises its head, spins strands of silk from its mouth, and swings left and right up and down to find a place to form a cocoon.

Preparing for silkworms to spin silk and form cocoons

The silkworm is about to spin silk, what should we prepare for it?

Prepare a place for silkworms to spin silk: use straw to tie a small frame, and paper to make a cylinder or grid room. Once the silkworm is found to be mature, it can be placed in a lattice or shelf.

Target Detection

fill in the blank:

1. During the growth process of silkworms, (body length), color, (eating situation), defecation, activities, etc. are constantly changing;

2. When silkworms grow to a certain stage, they will grow new skin and replace the old skin. This is called (molting);

3. The shape of silkworm is (long cylinder), and its body is divided into three parts (head), (thorax), and (abdomen); it uses (mouthparts) to eat mulberry leaves, uses (abdomen) to crawl, and uses (spiral valves) to breathe. ;

4. When the silkworm's body turns yellow and shiny and stops eating, it will (spin silk).

①How many times did you find that silkworms shed their skin?

②How long does it take to shed the skin?

③What are the abnormalities in silkworms before molting?

④What is the difference between silkworms before molting and after molting?

⑤Do you think your silkworms will still shed their skin?

⑥Why do you think silkworms molt?

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For more information about the PPT courseware "The Life Cycle of Animals and the Growth and Changes of Silkworms", please click the "The Life Cycle of Animals and the Growth and Changes of Silkworms" ppt tag.

Download the PPT "Growth and Changes of Silkworms" Animal Life Cycle:

"Growth and Changes of Silkworms" Animal Life Cycle PPT Download Part One: Introduction of New Knowledge Talk about it. Students, what is this fluffy little thing? How does it develop? What did you discover while recording your observations? What are ant silkworms like? The color is brown,...

"Growth Changes of Silkworms" Animal Life Cycle PPT:

"Growth and Changes of Silkworms" Animal Life Cycle PPT Part One Content: Communicating the Growth and Changes of Silkworms What changes have happened to the small silkworms? Share your silkworm raising experience with your classmates. When silkworms grow to a certain stage, they will grow new skin and replace the old skin. This is called molting. silkworm..

"Growth Changes of Silkworms" Animal Life Cycle PPT Courseware:

"Growth and Changes of Silkworms" Animal Life Cycle PPT Courseware Read pages 24 to 26 and think about the following questions: 1. As the silkworm grows, what changes will happen to it? 2. What is molting? Why do silkworms shed their skin? 3. What parts does the external shape of silkworm consist of?

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Update Time: 2024-11-18

This template belongs to science courseware Third Grade Science Volume 2, Textbook Edition industry PPT template

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