Why tamper with evolution by protecting endangered species?

It is said that extinction is a natural occurrence in evolution. Even though this is true, scientist believe that we should still save some species because they are dying before evolution can happen. The extinction of just one species can have a drastic impact on many other species. The only way protecting endangered species could be considered tampering with evolution is by killing species faster than evolution. As said by PBS, “No species exists in a vacuum”, no one species is isolated so every species has an effect on the other.

In today’s society there are many organizations working to save endangered species. These organizations realized that all species play a role in another’s life. If we were to lose a large number of one species there will be no food for the species that feed on them. Which would lead to the death of several species until we are all gone.

Many think of saving endangered species as tampering with evolution as said by Sheila Conant, Professor, and Department of Zoology University of Hawaii.  She believes that the endangerment of species is a natural process. She says this because a majority of the time species becomes endangered because their habitat has inadequate food quality or amount. This lowers the chances of an animal’s reproduction, and survival.

When we move an animal for instance moving polar bears to America because the are endangered that is an example of tampering with evolution because we are removing the species from its natural habitat, which is tinkering with its food, and natural reproduction abilities.

Questions

 - Since we believe animals evolve, why  aren't new species with similar but better characteristics created from evolution before extinction occurs?

- Is it possible to speed up the process of evolution?

- Do species become extinct not just because they can't survive in the present conditions but because they have no chance of survival in the future ?

Sources
http://www.pbs.org/wgbh/evolution/library/faq/cat08.html#Q03
http://jhered.oxfordjournals.org/content/101/4/437.abstract
http://www.jstor.org/pss/1310848

http://www.ncbi.nlm.nih.gov/pubmed/20332163

http://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_02