"Silkworms have changed their appearance" Animal life cycle PPT courseware 2

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"Silkworms have changed their appearance" Animal life cycle PPT courseware 2

The formation of silkworm chrysalis (yǒng)

What kind of skills does the silkworm baby practice inside the cocoon? Use scissors to carefully cut a cocoon in a straight direction. Wow! The silkworm baby has turned into a pupa, and there is still a set of outer skin inside the cocoon. This is the coat that the silkworm sheds when it molts and turns into a pupa. At first, the pupa is white and soft, then slowly changes color, and finally becomes brown and hard. Generally speaking, one may think that silkworms are resting in their pupae. In fact, major structural changes are taking place in the body of the pupa. On the one hand, the body in the larval stage is destroyed, and on the other hand, the body of the moth is created. The amazing thing is, they all happen at the same time.

Why does silkworm make a cocoon to wrap itself?

Because the pupa cannot move and has no ability to resist, if it is not wrapped up, it will be eaten by birds or other things, or it will be killed by the rain. To cover oneself is to protect oneself.

How is the appearance of a pupa different from that of a silkworm?

Silkworms have a long cylindrical body shape. The body is bluish white and divided into three parts: head, chest and abdomen. The head is very small.

The pupa has a stubby body shape, spindle shape, and is divided into three parts: head, thorax and abdomen, dark brown, with a small head.

The value of silkworm chrysalis

According to data, silkworm pupae are of relatively high value. my country began to steam and eat silkworm pupae more than 1,400 years ago. Silkworm chrysalis is rich in protein and a variety of amino acids. It is an advanced nutritional supplement for the frail, post-ill, elderly and postpartum women. Silkworm chrysalis can produce pharmacologically active substances, which can effectively increase the level of white blood cells in the human body, thereby improving human immune function and delaying the aging of human body functions. Silkworm chrysalis oil can lower blood lipids and cholesterol, and is significant in treating hypercholesterolemia and improving liver function. effect.

How long is the silk in a cocoon?

Silkworm cocoon is composed of silk. The silk of a silkworm cocoon is generally 900-1500 meters long in spring cocoons and 700-1200 meters long in summer and autumn cocoons.

Summarize

① The silkworm before turning into a pupa is a larvae in the growth and development process of the silkworm, and the pupa is another form in the growth and development process of the silkworm. The appearance of pupae is very different from that of larvae.

② Silkworm pupae are wrapped in cocoons, and the cocoons can protect the pupae.

③A silkworm cocoon is composed of a piece of silk, which can be woven into silk or processed into various silk fabrics.

Operation

1. Go home and collect information about silkworm chrysalises to better understand them.

2. Preview the lesson "What Becomes a Chrysalis".

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For more information about the PPT courseware "The Life Cycle of Animals, Silkworms Have Changed Their New Looks", please click the "The Life Cycle of Animals ppt, Silkworms Have Changed Their New Looks" ppt tag.

"Silkworm Has Changed Its New Look" Animal Life Cycle PPT Download:

"Silkworms Changed a New Look" PPT Download of Animal Life Cycle Part One: Introduction of New Knowledge Thinking: Students, do you know what will happen after spinning silk? So do you know what a silkworm chrysalis looks like? What are silkworm cocoons used for? With this question...

"Silkworm Has Changed a New Look" Animal Life Cycle PPT:

"Silkworms Changed a New Look" Animal Life Cycle PPT Part One: Observing Silkworm Chrysalises The silkworms spin silk, and the silk tightly wraps the silkworms. Why does a silkworm make a cocoon to wrap itself up? What becomes of the silkworm in the cocoon? Is the silkworm inside the cocoon still alive? us..

"Silkworm Has Changed Its New Look" Animal Life Cycle PPT Courseware 3:

"Silkworm Has Changed a New Look" Animal Life Cycle PPT Courseware 3 Why does silkworm make a cocoon to wrap itself? Because the pupa cannot move and has no ability to resist. If it does not wrap itself, it will be killed by birds and the like. Eat it, or die in the rain. Wrapping yourself up is protection...

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Update Time: 2024-09-09

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

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