
...by having variation, a species has more chance that at least some of its members will be able to survive under whatever pressures a changing environment brings.
this process is very difficult to observe.
Let us consider an imaginary population of leaf-eating insects.
Most biologists would say that evolution by natural selection is no longer a theory, but fact…nevertheless there are still very many unanswered questions.Despite these unanswered questions, the textbook does not present a scientific controversy over evolution. Rather, any controversy is seen as religious:
When, in 1859, Charles Darwin first published his ideas…his book was met with horror by many people. The idea that species might change was not only against people’s religious beliefs, but also against their instinctive beliefs…Worst of all was the suggestion that humans might not have been created as humans, but evolved from something similar to a monkey or ape. It is not surprising that these views provoked controversy and impassioned argument. Indeed, in some communities and religious groups they still do today.