It is natural process of animal species to become extinct (e.g. dinosaurs, dodos etc.). There is no reason why people should stop happening this.
To what extent do you agree or disagree?
People have to admit that natural selection is the rule of nature ←表语部分的内容还是笼统的概念，换用“同位语从句”引出具体内容→ the nature's law that some species of animals die out because they are unable to adapt to the environmental change. , so it is reasonable that some animals die out. However, this does not represent mean that people cannot should not stop the extinction of animals. As a matter of fact, there are some reasons for people to stop it 词汇升级→ intervene.
Admittedly, in many cases, natural selection is a rule which we even the mighty humans need to obey because it benefits to the environment ←多余信息.For example, the food chain position of a local bird is may no longer exist because its incapability of replaced by a foreign specie which is more adaptable to local surviving the changed environment, then the original one will be extinct. ←简化内容和逻辑。However, it doesn't does not mean that people should not stop happening this humans' intervention is not needed. In fact, the extinction of some animals are is due to human activities, such as logging that destroys the habitats of some wildlife and conversion of the wilderness into farmlands, instead of natural the nature's selection of certain species and elimination of others. ← 换一个方式说natural selection咯。【可惜反驳部分的内容和题目给定的内容冲突了。】→ In fact, although the extinction of some animals is part of the development of nature, it needs to be stopped by external forces in order to prevent the adverse impact, which may be too heavy on humans. For example, the lack of a bird species in a local ecosystem may lead to the overpopulation of a species of insect, and the insect may spread so widely and densely that farmlands are destroyed.
As a matter of fact, it is only when some animals are available that the balance and diversity of the environment can be kept keep balance. In some areas, which the environment is poor and food chain is simple, ←多余的信息 the extinction of one a kind of animal whose lack may represent a link cause the degradation of the localecosystems which will have a huge impact on environment has to reproduce so that the wellbeing of the local ecosystems can be maintained. For example, one kind of mouse' extinction in the north of China lead to the proliferation of pests that leads to the damage of environment. an animal whose activities are underground may be favorable to the fertility of soil, and the disappearance of this animal species renders the soil infertile.【接下来的部分的内容和题目给定的内容冲突了。】Meanwhile, the extinction of certain animals because of human should be rescued. It is no denying that many buildings and plants take up animals habitats, so they loose their shelters from the storm. If mounting animals extinct due to human activities, people should definitely save those animals as well as themselves. → Another reason is a rather general one. Humans should not let the nature take its own course, because if the nature were kept in its natural state, many disasters would be highly likely to happen. ←注意此处故意用了虚拟语气。In fact, humans have historically intervened and successfully prevented many disasters. This principle also applies to animal extinction as part of the natural process, which cannot be left alone.
In conclusion, although people should not stop interfere with the natural process of animal extinction, due to because the nature develops by natural its own law of selection. However, it is would be ←注意此处故意用了虚拟语气。unfavorable disadvantageous for the two aforementioned reasons mentioned above.