| − | Specifically, Darwin claimed that a mechanism of survival-of-the-fittest enabled more advanced and more complex members of a species to survive while the weaker ones would die off. Somehow more advanced members of a species could then produce entirely new species, though there is no evidence of that and no one has explained how that could ever happen. | + | Specifically, Darwin pointed out that organisms with favorable traits are more likely to survive and reproduce than those lacking those traits or possessing unfavorable traits. Over time this mechanism might allow those favorable traits which are inheritable to become more common. |