Learning focus:

Screen the main points of view

Second, screen key sentences.

As a naturalist, I once participated in the round-the-world voyage of the cruiser Beagle, and I was deeply impressed by the biogeographic distribution of South America and the geological relationship between existing organisms and paleontology. After I returned to China, it occurred to me at 1837 that if I patiently collected all kinds of information related to this issue and sorted it out, I might gain something. In this way, in five years, I concentrated on studying this problem and made some notes. 1844, these notes were enriched and written as an outline of what I thought was the correct conclusion at that time. Since then, until now, my discussion on this issue has never stopped. I hope readers will forgive me for saying these trivial things. I explained them to show that I didn't jump to conclusions.

Now (1859) my work is almost over; But it will take more years to complete it all, and my physical strength is getting more and more tired, so I have to print this summary first. Mr. Wallace (4), who is now studying natural history in Malay archipelago, has almost the same conclusion about the origin of species as I do, which is one of the reasons why I published this abstract as soon as possible.

This book is still abstract in nature and may be incomplete; There are many discussions, but I can't point out its source and reference materials, but I hope readers will believe me. At the same time, although I try to be cautious and let everything be based on correct evidence, I will inevitably make mistakes. This book deals with only the general conclusions I have drawn, and gives several facts as examples. I hope readers don't think it is too simple. I look forward to and feel the need to publish in detail all the facts and reference materials on which I am based in the future. Because I know very well that there is almost nothing discussed in this book that cannot be proved by citing facts, and every argument obviously often leads me to some completely opposite conclusions. When we deal with a problem, we must describe and compare two facts and evidence in detail, and then we can get a perfect result, but it is impossible here.

Regarding the origin of species, if a naturalist thinks about the fact that organisms are interrelated (5) the relationship between their embryos, their geographical distribution and the procedures that appeared in geological periods, then we can infer that biological species, like varieties, evolved from other species before, rather than being created alone. This conclusion, even if it is well-founded, is not satisfactory if it can't explain how countless creatures on the earth undergo mutation to achieve their extremely perfect structure and mutual adaptation. General naturalist; External environment, such as climate, food, etc., is often considered as the only possible reason for variation. In a narrow sense, this is correct, which will be discussed later; However, if a structure like a woodpecker, its feet, tail, mouth and tongue are so skillfully adapted to catching insects in bark, it is unreasonable to attribute it only to external conditions. Mistletoe (7), which grows on some trees to absorb nutrients, needs birds to spread seeds. Because it is dioecious, it must rely on insects to complete pollination; It is also unreasonable to explain the structure of this parasitic plant and its relationship with several other organisms only by the external environment, or the influence of plant habits, or the tendency of plants themselves.

Therefore, we urgently need to have a clear understanding of the causes and methods of biological variation and mutual adaptation. At the beginning of my research on this subject, I felt that to solve this problem, we should start with studying domestic animals and cultivating plants; Sure enough, I didn't disappoint. I often get the knowledge that animals mutate because of domestication. Although it is not complete, it can always provide the best and most reliable clues for dealing with this problem and all other complex events. Therefore, although this kind of research is often ignored by general naturalists, I believe it is very valuable.

For the above reasons, I put the problem of domestic variation in the first chapter of this book. We will see from this that a large number of genetic variations are possible; Similarly, or more importantly, we will see the greatness of human seed selection ability, which can gradually accumulate tiny variations. Then, we will discuss the variation of species in the natural state. Unfortunately, what I say here must be very brief, because in order to discuss this problem properly, a lot of facts must be quoted.

If we realize that we still don't know much about the interrelationships of many creatures living around us, it's not surprising that we can't explain the origin of species or varieties. Why is a certain species widely distributed, while its neighboring species are narrow and rare? Who can explain this problem? However, these relationships are really important, because I believe that this determines the present and future fate of every living thing on earth, as well as the trend of variation. We know less about the interrelationships of countless creatures living in the past geological times. Although many facts are still unclear and will not be clear for a long time to come, after careful study and calm judgment, we can undoubtedly assert that creationism is wrong. The idea of creationism, though believed by many naturalists in modern times and once believed by myself, can never be established in fact. I am convinced that the species of living things are not constant; The so-called homologous species are all direct descendants of other species that are likely to be extinct, but now it is considered that all varieties of the same species are descendants of the same species. I am also convinced that although natural selection is not the only condition for species variation, it should be the most important condition.

(1) from the origin of species Chinese version (science press), the original title is "introduction", with abridgement. The first edition of the original work was published in 1859. Darwin (1809- 1882) was a British naturalist and the founder of evolution. Species, the basic unit of biological classification, is the meaning of species. Biological classification uses several taxonomic units, which are generally divided into species, genera, families, orders, classes, phylum and so on. Introduction introduction.

(2) [I used to sail around the world as a naturalist] From 183 1, Darwin, as a natural scientist, sailed around the world for five years free of charge on the cruiser Beagle, and made a lot of observations and collections on animals, plants and geology, and returned to China in 1836. Natural history, the general name of animals, plants, minerals, physiology and other disciplines in the old days.

(3) (Now (1859) my work is coming to an end ... more years) Darwin thinks that the Origin of Species is only an introduction to his theory of biological evolution, so he says so. Later, he discussed various problems of evolution in more detail, further enriching the content of evolution.

(4) Wallace (1823- 19 13) is a British natural scientist. 1858, he wrote a scientific paper on natural selection of biological evolution and sent it to Darwin. Darwin also published his research results and Wallace's paper in the Journal of Linnaeus Society.

⑤ 【 Kinship 】 refers to the close relationship between organisms in species. ⑥ [Variation] refers to the difference of traits between generations of the same organism or between different individuals within the same generation.

⑦ 【 mistletoe (hú) parasitism 】 A small parasitic shrub, which is mostly parasitic on the trunks of mistletoe, chestnut and other trees.

(8) Taxonomic units below species refer to individuals or groups of individuals with significant variation. Individuals with significant variation are equivalent to subspecies (for example, Northeast Tiger and South China Tiger are two subspecies).

9 [Creationism] A fallacy that every species is created by God.

practise

Read the text quickly and screen out two main viewpoints on the origin of species elaborated by the author.

Second, filter the sentences in the text as required.

1. The purpose of the author's research on domestic animals and cultivated plants.

2. The significance of the author's research on domestic animals and cultivated plants.

3. The author got two understandings from studying domestic animals and cultivated plants.

The three authors believe that there are still many questions about the origin of species that need to be clarified. From which two aspects does paragraph 7 of the text summarize these problems?

Of the six items after the following long sentences, which are essential to summarize the main points of long sentences? Regarding the origin of species, if a naturalist is interested in the genetic relationship between organisms, the relationship between their embryos, the geographical distribution and the procedures that appeared in geological periods. Facts, thinking, then, we can infer that biological species, like varieties, evolved from other species, rather than being created separately.

1. Background of studying the origin of species

2. Study the factual basis of the origin of species.

3. Methods of studying the origin of species

4. Inference of the origin of species

5. Criticism of wrong theory

6. Different understandings of the origin of species