Third Grade Science Volume 2, Textbook Edition

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"Silkworms have changed their appearance" PPT courseware on the life cycle of animals

The formation of silkworm chrysalis

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 of the larvae is destroyed, and on the other hand, the body of the moth is created. The amazing thing is that they all happened at the same time

1. Pre-pupa. 2. Start peeling. 3. Complete shedding of skin 4. Become a pupa 5. Complete metamorphosis

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. You have to cover yourself to protect yourself.

What is the difference between the appearance of pupae and silkworms:

The pupa body is short and short, spindle-shaped, divided into three parts: head, thorax and abdomen. The head is small, the body is shortened and brown.

The body of silkworm is long cylindrical, divided into three parts: head, chest and abdomen. The head is small and the body is bluish white.

The value of silkworm chrysalis

According to data, silkworm pupae are of relatively high value. my country began to cook 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 the body's 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.

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.

2. ABC of happiness

1. A silkworm turns into a pupa in the cocoon it spins. The appearance of pupae and silkworm babies ( ).

A. Completely different B. Exactly the same C. Similar

2. Silkworm cocoons can be spun. When spinning, we need to use the ( ) tool to pick out the thread ends and wind them around the thread board.

A. Finger B. Bamboo stick C. Sewing needle

3. In order to pull the silk out of the cocoon, what kind of treatment should be done to the cocoon first? ( )

A. Soak the silkworm cocoons in cold water first

B. Soak the silkworm cocoons in hot water first

C. Put the silkworm cocoon in the refrigerator first.

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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:

"Silkworm Has 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: 2024-06-27

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