What is meant by the term evolution?

Hint: Life first originated from one unicellular organism. This organism gave rise to all of the organisms that we see on the earth today. Thus the way that organisms are able to change their traits and evolve is known as evolution.

Complete answer:
The various organisms on the earth have all evolved from one single organism that existed a long time ago. Thus in order to survive in the world, organisms need to adapt to their surroundings. To do this organisms change their traits and their genes to give them the best chance of survival. This is the theory that Charles Darwin formulated that was called natural selection. This theory describes the survival of the fittest. Thus only those organisms that were able to survive and thrive in their habitat would be able to evolve and procreate.
The term evolution refers to the changes that come about due to adaptations. These changes are able to alter the genes of the organism. Thus the changes get passed down to the offspring of the individual. This evolution usually happens over long periods of time but certain changes also happen in short spans of time.

Note:
Evolution is a term that is used to describe the genetic changes that occur in organisms as they evolve. Evolution is the reason that organisms are able to adapt to their surroundings and evolve into different species.