"Plant Reproduction" Biological Reproduction and Development PPT Courseware 2

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"Plant Reproduction" Biological Reproduction and Development PPT Courseware 2

Think about it:

1. Why has life continued to exist on the earth since it appeared until now?

2. Some people say: "In this world, there are chickens first and then eggs." But some people hold the opposite view and believe that "there are eggs first, then chickens." Who do you agree with?

Think again:

1. What are the reproductive methods of organisms on earth? Can you recall what you learned?

2. Do you know which type of plant is the most widely distributed on the earth and most closely related to humans?

We know that flowers develop from flower buds. So, what important processes does a plant go through from the emergence and formation of flower buds to fruiting?

Flowering, pollination and fertilization are necessary before the ovary can develop into a fruit.

1. Sexual reproduction

What is "sexual reproduction"?

------- Reproductive method in which the reproductive cells of both sexes combine to form fertilized eggs, and then the fertilized eggs develop into new individuals.

2. Asexual reproduction

What is asexual reproduction?

The process of developing directly from the mother into a new individual without the combination of reproductive cells of both sexes.

discuss:

1. What do these plants have in common in their reproductive methods?

Answer: They all produce new individuals directly from the mother without going through the combination of reproductive cells of both sexes. (This method of reproduction is called asexual reproduction)

2. Plant reproduction methods are diverse.

Asexual reproduction produces offspring individuals relatively quickly (sexual reproduction generally takes a longer time), which is conducive to the reproduction of a large number of individuals in a short period of time under suitable environmental conditions, and the traits of the offspring are relatively consistent.

Seeds, fruits, etc. produced by sexual reproduction can often tolerate adverse environmental conditions and are easily spread to other places through various media, expanding the distribution range of plants. In addition, sexual reproduction can make offspring have the genes of both parents, have a stronger ability to adapt to environmental changes, and is more evolutionary meaningful.

3. Application of Asexual Reproduction

In production practice, people often use asexual reproduction of plants to cultivate crops and garden plants. Do you know why?

Advantages of asexual reproduction:

1. Save time; 2. Increase output;

3. Improve quality; 4. Innovate varieties.

Practice in class

Based on Figures 1 and 2, please answer the following questions:

1. Grafting includes two methods. The method shown in Figure 1 is___

The method shown in Figure 2 is ___.

2. The difference between the two grafting methods is the scion. Figure 1 uses ___ as the scion, and Figure 2 uses _____ as the scion.

summary

Notes on grafting:

1. In order to ensure the survival of the scion, the cambium layer of the scion and the rootstock should be tightly combined (when the scion is smaller than the rootstock, the cambium layer on one side should be docked)

2. When binding with plastic tape, pay attention to tightening it to prevent rapid evaporation of moisture at the joint or entry of external rainwater.

Practice questions

1. The main structure of a peach blossom is ( )

A. Torus B. Petals C. Stamens D. Ovules

2. Which of the following organisms can reproduce both sexually and asexually? ( )

A. Frog B. Peach tree

C. swallow D. giant panda

3. Among the following structures, which one can develop into a new generation of plants ( )

A. Flower B. Ovary

C. Pollen D. Fertilized egg

4. What kind of reproduction method does "unintentional planting of willows and willows create shade" refer to? ( )

A. Seed propagation B. Cutting propagation

C. Grafting propagation D. Layering propagation

5. Among the following crop reproduction methods, which one is sexual reproduction? ( )

A. Lychee propagation by grafting

B. Propagate grapes by cuttings

C. Propagate corn from seeds

D. Propagate bananas by dividing roots

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For more information about the PPT courseware "Reproduction and Development of Organisms and Reproduction of Plants", please click the Reproduction and Development of Organisms ppt Reproduction of Plants ppt tag.

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Update Time: 2024-11-20

This template belongs to biology courseware People's Education Edition Biology for Grade 8, Volume 2 industry PPT template

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