"Animals in the Soil" Plant Life Land PPT Courseware

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"Animals in the Soil" Plant Life Land PPT Courseware

Explore the characteristics of earthworms adapting to life in the soil

1. Observe the morphological structure of earthworms

2. Think about where the “home” of earthworms is?

Earthworms live in moist, loose soil rich in organic matter. Earthworms burrow in the soil during the day and crawl to the ground at night (living in the day and emerging at night), feeding on organic matter in the soil or plant stems and leaves.

3. Think about whether earthworms have “legs”? How do earthworms move?

Under a magnifying glass we can see that it has bristles on the outside, just like our human feet.

The movement principle of earthworms.

It relies on the contraction and relaxation of muscles to provide the power for movement, and coordinates with the bristles to complete the movement.

illustrate:

1. There is a brain at the front end of the earthworm, and the brain extends backward into the ventral nerve cord. Therefore, earthworms respond more sensitively and accurately to stimulation.

2. Earthworms have no eyes and have a large number of photoreceptor cells on the surface of their body, especially at the front end.

3. Earthworms have no ears, but there are many sensory cells on their body walls. They can feel any small vibration from the outside.

4. Earthworm’s Breath

Earthworms do not have specialized respiratory organs and rely on their moist body surface for gas exchange. (The moist and slimy body surface can also reduce the friction between the body and the soil surface)

Discussion 1: Why do earthworms crawl to the ground when it rains?

The rain squeezes all the air out of the soil, making earthworms unable to breathe and forced to crawl to the ground to breathe.

Discussion 2: Why is it easy to dig earthworms on the soil surface in summer, but have to dig deep in winter?

Earthworms cannot maintain a constant body temperature. In winter, the temperature and humidity in the deep soil are higher and there are fewer enemies, which is suitable for their survival.

Summarize the characteristics of earthworms adapting to cave dwelling life:

1. Body shape:

Slender cylindrical shape reduces resistance when drilling into soil.

The body segments allow for flexible and free movement.

2. Breathing: Use the moist body surface to breathe; the mucus on the body surface can lubricate and reduce the friction of drilling soil.

3. Movement: Relying on the coordination of muscles and bristles.

4. Nervous system: It is more developed and can respond more sensitively and accurately to stimuli. (It has no eyes, but has a large number of photoreceptor cells on the body surface, especially at the front end)

Earthworms are full of treasures and are receiving more and more attention from people. Their functions include:

1. Improve the soil and increase soil fertility;

2. Dispose of domestic waste;

3. Use as feed;

4. Used as traditional Chinese medicine, "earth dragon";

5. Make health food and medicinal diet;

6. Use earthworms as raw materials to make light chemical products such as cosmetics, food and feed additives.

1. Earthworms live in the soil. Which of the following statements is incorrect ( )

A. Earthworms are arthropods

B. Earthworms can break down organic matter in the soil

C. Earthworms can move their bodies through the cooperation of muscles and bristles.

D. The respiration of earthworms depends on the body wall that secretes mucus and remains moist at all times.

2. The following surface is most suitable for earthworms to move on ( )

A. glass plate b. cardboard

C. Porcelain plate D. soil

3. Earthworms are small animals that lie dormant during the day and emerge at night. ( )

4. After thunderstorms, earthworms often emerge from the ground. This phenomenon is related to which physiological process of earthworms is hindered?

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Update Time: 2024-11-24

This template belongs to science courseware People's Education Press third grade science volume 2 industry PPT template

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