2003-7-29 23:0 1:30 Yonghe middle school read 2 133 times.

Research Group of Class Six, Grade Seven

Members: She Qiren, Cai Xiaobin, Weng Weiqiang

Cai, Deng, Yang

Instructor: Bao, Di Guilan

The topic of our group study is "earthworm regeneration", and we divide the work like this: field investigation: members of the whole group; Internet access: He Cai; Visiting experts: Deng, She Qiren, Cai; Written information: Weng Weiqiang, Cai Xiaobin; Summary paper: members of the whole group. Our final report is:

Put forward an experiment

I remember when I was a child, we often went to the river to catch earthworms and then went fishing. I remember that the earthworm was still moving after we cut it into four or five sections. A few days later, when I went fishing again, some earthworms died while others got into the soil. We are very puzzled about the regeneration of earthworms, but we have consulted many students, and they are as unclear as we are. Therefore, we set the goal of inquiry learning: the regenerative ability of earthworms.

We got many answers in a biology book: Earthworms, like geckos, contain biological organs-regenerative organs. This organ can regenerate earthworms after decomposition. If this organ is destroyed, maybe the earthworm can't regenerate. When the earthworm is decomposed, it will secrete a yellow sticky substance to wrap the wound, so that it can come back to life. If the reproductive organs of earthworms were not found to be divided, the survival and extinction of earthworms would still be a mystery, but now we have been further observing and experimenting, so we made the following assumptions.

Suppose: we break down earthworms into

1, divide the earthworm into two sections.

2. Divide the earthworm into four sections.

3. divide the earthworm into five sections

Will it survive?

experimental method

We are interested in the regeneration ability of earthworms. Therefore, we have made a new experiment on the regeneration ability of earthworm. We excitedly came to a small ditch with tools and grabbed earthworms.

We took five earthworms, prepared all the experimental tools and did the following experiments:

1. We took five plastic boxes, which contained 70% soil, and the soil moisture was about 80%. Then we put five earthworms into five boxes respectively. Each box is placed according to the number of A-B respectively.

2. Cut five healthy earthworms as follows: a, cut off two limbs (except the mouth) at both ends of the earthworms; B, cutting off six limbs at the front end of the earthworm (cutting off important organs such as mouth, pharynx, esophagus, suprapharyngeal ganglion and hypopharyngeal ganglion); C, cutting off six limbs at the rear end of the earthworm (cutting off anus and a small part of intestine); D, cutting off one third of the rear end of the earthworm (cutting off the anus and a part of the intestine); e.

3. After cutting five earthworms with a scalpel, put them into the corresponding plastic iron box, put some soil with more water, cover it, and then put the box in the dark.

4, put it in the dark, and then observe it every two days, and record the changes of earthworm wound cutting, pay attention to keep the humidity of the soil.

observed result

We observed the normal regeneration of earthworms on March 20th, and our group cut the earthworms into two or three sections. The wounds of some earthworms have basically healed, but some earthworms still haven't healed. We didn't observe them on March 2 1 day and March 22, but on March 23, we found that a large number of earthworms had died, some alive earthworms' wounds were only basically healed, and some had completely healed. Although some experiments were unsuccessful, our group carefully analyzed the experimental phenomenon of earthworm regeneration ability. We encourage students to further improve their experiments. After analysis, we have reached the following preliminary conclusions: 1. Earthworms have strong wound healing ability. 2. The filter paper is not wet enough to keep the earthworm moist, which leads to dyspnea and death. 3. Individual earthworms are thin and have poor resistance. 4. There is no purity in the Petri dish, and bacteria infect the earthworm wound. In view of the above reasons, we improved the experiment.

Experimental process and conclusion

I first came to a fertile land, caught two earthworms and put them on the board. Then I took out a sharp scalpel from home and cut them in the middle. Earthworms were cut in half by us. Earthworms rolled on the board and sometimes some mucus flowed out. These mucus stopped the bleeding and revived the earthworm's wound. Earthworms will release mucus, and at the same time, their bodies will shrink continuously, and finally they will be wrapped into a shell. I took an iron box, almost 20 cm long, put earthworms in the box, the humidity of the soil in the box was 80%, and then put the box in wet, loose and organic soil.

Then I put the second one on the chessboard, cut the earthworm into four sections with a scalpel, some moved and some didn't, just like just now, and released mucus to repair the broken body. Finally, I put the earthworm in an 8 cm high box, and finally I made a list:

Number of cut segments Number of live segments Percentage of live segments

2

2

100%

four

2

50%

five

2

40%

conclusion

According to the above experiment and table. We have reached the following conclusion: 1. Earthworms have strong wound healing ability. 2. Earthworms have strong regeneration ability, and organs with simple structures can grow again after being cut off. However, it is difficult for organs with complex structures to grow back after being cut off. For example, after the heart, gizzard, reproductive organs and other important organs are removed, earthworms can no longer survive.

After many experiments, we think that earthworm has very strong regeneration ability, but this gene in our body is dormant. I believe that in a few years or decades, if the scientific research is successful, the mutilated limbs of the human body can grow back. This will greatly benefit mankind and the world. There will be no disabled people in the world, and our life will be colorful and interesting.

Feelings and experiences

In this study, we studied the regeneration of earthworms. In this study, although we have a lot of doubts, through continuous research and experiments, we finally reached the above conclusion. At the same time, we have gained a lot of experience, for example, we encountered many difficulties in the experiment, which also strengthened our perseverance and let us know how to solve some difficulties. Also let us understand: as long as there is pay, there will be gains.