People's Education Edition Biology for Grade 8, Volume 1
People's Education Edition Biology for Grade 8, Volume 2
People's Education Press High School Biology Compulsory Course 2
People's Education Edition seventh grade biology volume 1
Beijing Normal University Edition Seventh Grade Biology Volume 2
Beijing Normal University Edition Eighth Grade Biology Volume 1
People's Education Press seventh grade biology book volume 2
Beijing Normal University Edition Seventh Grade Biology Volume 1
Beijing Normal University Edition Eighth Grade Biology Volume 2
Jiangsu Education Edition 8th Grade Biology Volume 1
High School Biology Compulsory Course 1, published by People's Education Press
Jiangsu Education Edition Seventh Grade Biology Volume 1
Jiangsu Education Edition Seventh Grade Biology Volume 2
Jiangsu Education Edition 8th Grade Biology Volume 2
!["Reproduction and Development of Amphibians" Reproduction and Development of Biological Organisms PPT Courseware 2](http://daogebangong.oss-cn-beijing.aliyuncs.com/ppt/preview/1/6f094a13-59bd-4c6e-9312-ae2308a17f5f.webp)
Category | Format | Size |
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People's Education Edition Biology for Grade 8, Volume 2 | pptx | 6 MB |
Description
"Reproduction and Development of Amphibians" Reproduction and Development of Biological Organisms PPT Courseware 2
1. Reproduction of frogs
What's the meaning of the frog's cry?
Courtship, attracting female frogs to cuddle with each other
The male frog has a pair of singing sacs at the corners of its mouth, which bulge and then deflate. During the breeding season, male frogs chirp as a way to court mates, so frog chirping is of great significance to the reproduction of the population.
What is the significance of the frog's embrace?
in vitro fertilization
Holding the baby right will help the semen to be discharged directly onto the egg cell, which will increase the fertilization rate of the egg.
2. Development of frogs
Developmental characteristics of frogs: metamorphosis
There are significant differences between larvae and adults in terms of morphological structure and living habits.
Amphibians:
The larvae live in water and breathe with gills; they metamorphose and develop into adults; the adults live on land or in water, breathing mainly with lungs and assisted by skin.
3. The relationship between amphibian reproductive development and the environment
A survey of global amphibians conducted by scientists showed that the number of frogs, toads and salamanders around the world is declining. In 2004, 168 species of amphibians became extinct globally, and the survival of 1/3 of amphibians is threatened, mainly due to their natural habitats. The living space has been destroyed. Half of all amphibians may become extinct within the next 100 years.
discuss
1. Deformed frogs appear in some areas. What may be the cause?
Deformed frogs may be caused by water environment pollution, which will inevitably affect the survival of amphibians and lead to a decrease in their numbers.
2. What lessons have you learned from the above examples?
In order to protect all living things, including us humans, we must care for the environment, protect the environment, and prevent the environment from being polluted. Reduce the use of pesticides, discharge of sewage, and protect the water environment.
According to research by scientists, it has been proven that the reproduction and development of amphibians are inseparable from water, and adults need to live on land. This leaves most amphibians confined to moist areas near water.
Environmental change is also an important factor affecting the distribution of amphibians. As ponds, rivers, lakes and other water environments shrink, the distribution range of amphibians is also getting smaller and smaller.
Reasons for the decline of amphibians:
1. Self-cause: Reproduction and development cannot be separated from water
2. Environmental reasons: ① Climate drought ② Human activities
Practice in class
1. The _____ and _____ of amphibians must be carried out in the water, and the larvae must go through _____ before they can live on land.
2. Which of the following is not an amphibian? ( )
A. Giant salamander B. Turtle C. Frog D. Toad
3. The frog that can chirp is ( )
A. Female frog B. Female frog and male frog
C. Male frog D. Female or male frog
4. Which of the following are amphibians ( )
A. Turtle B. Giant salamander C. Crocodile D. Chinese sturgeon
5. The mature frog will return to the water ( )
A. Catch flies B. Get all the food
C. Breeding D. Moisten gills
6. The reproduction and development of frogs take place in �().
A. In water and on land B. In water
C. Proceed on land D. Proceed in mother body
7. The reproductive method of frogs is: ( )
A. In vitro fertilization, egg laying B. In vitro fertilization, metamorphosis
C. Internal fertilization, egg laying D. internal fertilization, metamorphosis
8. The ontogeny of frogs has gone through ( )
A. Egg----embryo----young frog----adult frog
B. Egg----embryo----tadpole----adult frog
C. Fertilized egg----tadpole----adult frog
D. Fertilized eggs----tadpoles----young frogs----adult frogs
Keywords: teaching courseware on the reproduction and development of organisms, teaching courseware on the reproduction and development of amphibians, new PEP eighth grade biology PPT courseware for the second volume, eighth grade biology slide courseware download, reproduction and development of organisms PPT courseware download, amphibians Animal Reproduction and Development PPT courseware download, .ppt format
For more information about the PPT courseware "Reproduction and Development of Biological Reproduction and Development of Amphibians", please click the Reproduction and Development of Biological Things ppt Reproduction and Development of Amphibians ppt tag.
"Reproduction and Development of Amphibians" Biological Reproduction and Development PPT Courseware 6:
"Reproduction and Development of Amphibians" Reproduction and Development of Organisms PPT Courseware 6 Amphibians contain two meanings: First, from the perspective of the evolutionary history of vertebrates, amphibians are a group that transitioned from aquatic to terrestrial. The second is from the individual findings of amphibians...
"Reproduction and Development of Amphibians" Biological Reproduction and Development PPT Courseware 5:
"Reproduction and Development of Amphibians" Reproduction and Development of Organisms PPT Courseware 5 Amphibians Larvae live in water and breathe with gills; adults live amphibious life, breathing with lungs and using skin to assist breathing. Such animals are called amphibians. Thinking about frog life..
"Reproduction and Development of Amphibians" Biological Reproduction and Development PPT Courseware 4:
"Reproduction and Development of Amphibians" Biological Reproduction and Development PPT Courseware 4 Questions before class 1. What stages does the development process of silkworm go through? 2. What are the similarities and differences in the external morphology of silkworm larvae and adults? 3. What stages does a locust go through in its development process? 4..
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Update Time: 2024-09-09
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!["Reproduction and Development of Amphibians" Reproduction and Development of Biological Organisms PPT Courseware 2](http://daogebangong.oss-cn-beijing.aliyuncs.com/ppt/preview/1/273661b4-06f7-4ddf-8c7b-9e48a9fdf3d0.webp)