What do evolution means?

Answer 1

Evolution just means "change" or "development" over time, so everything from the life cycle of a star to the movement of continents can be considered evolution.

Usually however when you hear the word "evolution" used in a scientific context it refers to biological evolution, which is the change in gene frequencies of a population over time.

What does this mean? All living organisms contain coded instructions or "genes," e.g. you have genes which determine your eye colour, hair colour, height, etc. Over many thousands, millions or even billions of years, the genes in a population of organisms can change, e.g. new genes appearing, certain genes becoming more common, etc. Say for example that the gene for brown eyes becomes more and more common over time, or that a new gene appears coding for red eyes. Those would be examples of evolution.

These small changes in the gene pool over a few generations may not seem like anything special, but they can add up over many centuries, millennia or even longer, producing entirely new traits and even new species - for example, small, gradual changes to their genes over millions of years allowed fish to develop lungs and limbs and crawl onto land; they allowed dinosaurs to develop warm blood and feathers and evolve into birds; and they allowed ape-like hairy ancestors to evolve into human beings.

That's the basic definition of what evolution is, but that's just a very very brief introduction to a huge and fascinating subject! If you want to know more, look up common descent, natural selection, speciation, the history of life on Earth, fossils, embryology, comparitive anatomy, genetic mutations, sexual selection, artificial selection, microevolution, antibiotic resistance, classification and taxonomy and more... evolution is a huge and interesting subject and I hope you're inspired to research further into it and ask more questions!

Answer 2

Evolution is the process through which the characteristics of species change over successive generations, typically through natural selection driven by environmental factors. It is a fundamental principle of Biology that explains how living organisms have diversified and adapted to their environments over time.