Darwin embarked as a naturalist, although he had no formal training and had recently left Cambridge University because he grew disinterested in his studies. But he was a very sharp observer of the natural world, and he lived at a time when a revolution in thinking was going on. Scientists were feverishly re-examining age-old questions, such as how old was the Earth? How did various features of the planet form?
Darwin was also fortunate that the Beagle took him to the Galapagos Islands, where he observed various animals and birds that had evolved in an isolated environment. His observations led him to his famous theory of natural selection. Are any of them extinct today? What types of plants did he note? What types of geology did he see? What would you imagine some of the hardships the explorers would have encountered on this voyage?
The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
The Rights Holder for media is the person or group credited. Tyson Brown, National Geographic Society. National Geographic Society. For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource. If a media asset is downloadable, a download button appears in the corner of the media viewer.
If no button appears, you cannot download or save the media. Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website. You cannot download interactives. This, by definition, is natural selection. The unequal ability between individuals to survive and reproduce will lead to gradual evolution of the population, with favourable characteristics accumulating over the generations through natural selection.
There are three key conclusions to be drawn from the theory of evolution: Natural selection is differential success in reproduction. Natural selection occurs through an interaction between the environment and the variability inherent among the individual organisms making up a population.
The product of natural selection in the adaptation of populations of organisms to their environments. Evolution is not progressive - Evolution is not designed to produce the best quality products, it only seeks to design adaptations 'that will do the job' most efficiently and economically. Therefore, evolution used the 'mammal template' throughout the development of all mammal species - eg. Evolution is not an argument for the status quo - Evolution does not dictate why things are the way they are.
It must be remembered that some of an animals features may be trade-offs or by-products of the evolution of an unrelated adaptation.
Evolution provides constraints - What has gone before sets physical limits on what we can do now.
0コメント