I believe that what is meant with the phrase "older explanation" is none other that superstition. Therefore, I will give you one superstitious belief which is now explained by science.
In Southeast Asia, people used to believe that St. Elmo's fire appears in remote areas because a bloody battle occured in that place leaving disembodied souls of the dead wandering there in the night and even in sunshine!
For generations, many people believed that this is a fact and some even say that these apparitions are diabolical or demonic in nature. So often, caution is advised to people whenever a ball of fire appears out in the open.
However, recent breakthroughs in the 21st century helped scientists to explain this mysterious phenomena. They found out that St. Elmo's fire is actually plasma, nothing special. Now, plasma is considered one of the states of matter! But mind you, it still does not explain why St. Elmo's fire seems to have a mind of its own!
Answer:
Organisms can adapt to their environment within one generation if they are selected naturally by the nature.
Explanation:
Organisms can survived which can withstand or tolerate the harsh climate of the environment while some organisms removed from that environment due to low survival ability in that harsh climate. This selection is done by nature in which well suited animals and plants can survive in that environment due to certain adaptations. Those organisms can adapt to their environment within one generation due to survival ability and high fitness.
For example, in deserts, bears did not survive because it requires cold climate so only reptiles such as snakes and lizards can survive in this environment.