"Linematids and Annelida" Main Groups of Animals PPT Courseware 2

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"Linematids and Annelida" Main Groups of Animals PPT Courseware 2

linear animals

Nematodes are so named because of their long and slender bodies. Some are parasitic, such as roundworms; some are free-living, such as Caenorhabditis elegans.

Please analyze the structural characteristics of roundworms. Which of them are suitable for parasitism in the human body?

The body is cylindrical, with a mouth and anus; the body surface has a cuticle, which plays a protective role; the digestive tract has a simple structure; the reproductive organs are well developed and the reproductive capacity is strong.

It has no specialized motor organs and can only move slowly.

What are the characteristics of roundworms that make them suitable for parasitism in the human body?

stratum corneum

Digestive tube structure is simple

Well-developed reproductive organs

No specialized motor organs

How do roundworms enter the human body?

Drinking water with insect eggs

Eating raw vegetables with insect eggs on them

Holding food with hands stained with insect eggs

What are the dangers of roundworms?

Roundworms live in the human small intestine and not only compete for human nutrients, but also cause a variety of diseases. The peristalsis of roundworms in the intestine can cause abdominal pain; the toxins secreted by roundworms are absorbed by the small intestine, causing mental restlessness, insomnia, irritability, night terrors, teeth grinding, cramps, headaches, etc.; if there are too many roundworms in the intestine, it can cause intestinal obstruction; the roundworms can burrow into the bile duct or appendix. , can cause biliary ascariasis or appendicitis; sometimes the roundworms can even break through the intestinal wall, causing peritonitis; too many roundworms invade the alveoli, causing pneumonia and other diseases.

How to prevent the occurrence of ascariasis?

Pay attention to personal food hygiene: do not drink unclean water, wash vegetables and fruits, and wash your hands before meals and after using the toilet.

Secondly, the feces must be managed well: the feces must be fermented to kill insect eggs before being used as fertilizer.

Main characteristics of earthworms:

(1) External form of earthworms:

Body shape: long cylindrical shape

Body: Many similar ring-shaped body segments

Body surface: mucus

Ventral surface: There are many small protrusions (setae), which feel rough to the touch.

(2) Movement of earthworms (muscles + bristles):

Rough paper: Movement is fast, the body becomes thicker and thinner, and it wriggles forward.

On the glass plate: the movement is slow, the body becomes thicker and thinner, but it is difficult to wriggle forward

(3) Earthworm breathing: moist body wall

(4) Digestion of earthworms: The intestinal wall has developed muscles and can peristalsis

(5) The benefits of earthworms to humans: they loosen the soil and improve soil fertility; earthworms themselves are rich in protein and are high-quality protein feed.

The relationship between lugworms, leeches and humans:

Nereis are food for fish, shrimps and crabs.

The saliva of leeches contains hirudin, a substance that prevents blood clotting and produces anti-thrombotic drugs.

Main characteristics of annelids:

The body is cylindrical and consists of many similar body segments; movement is assisted by setae and warty legs.

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For more information about the PPT courseware "The Main Groups of Animals Nematodes and Annelida", please click the Main Groups of Animals ppt Nematodes and Annelida ppt tag.

"Linematids and Annelida" Main Groups of Animals PPT Courseware 8:

"Nematodes and Annelida" Main Groups of Animals PPT Courseware 8 Nematodes Please analyze the structural characteristics of roundworms. What are the characteristics suitable for parasitism in the human body? The body is cylindrical, with a mouth and anus; there is a cuticle on the body surface for protection, and the structure of the digestive tract...

"Linematids and Annelida" Main Groups of Animals PPT Courseware 7:

"Nematodes and Annelida" Main groups of animals PPT courseware 7 Independent learning, cooperative exploration Reading and thinking: ⑴ What are the differences in the morphology of male and female roundworms? ⑵Where do roundworms infest? What are the feeding habits of roundworms? (3) What is the body structure of roundworms? What are the benefits of roundworms...

"Linematids and Annelida" Main Groups of Animals PPT Courseware 6:

"Nematodes and Annelida" Main Groups of Animals PPT Courseware 6 Exploring Observation Observe the roundworm specimens to see the difference in shape and size between male and female roundworms, as well as the characteristics of the body color and surface. Observe the internal structure of roundworms. What structural characteristics do you think of roundworms?

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Update Time: 2024-09-17

This template belongs to biology courseware People's Education Edition Biology for Grade 8, Volume 1 industry PPT template

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