Evolution

biology · change-over-time · adaptation · science

DNA gets passed down. Every creature inherits genes from its parents, and these genes carry instructions for what traits it will have. Over many generations, the mix of genes in a population can shift and change.

Natural selection favors winners. When an animal has a helpful trait, like a thick fur coat in a cold climate, it survives better and has more babies. Those babies inherit the same helpful trait, so the whole population gradually becomes better at surviving.

Diversity comes from small changes. Over millions of years, tiny changes add up until creatures become completely different from their ancestors. This is how all the incredible variety of life on Earth, from butterflies to bears, came from common ancestors long ago.

Random changes happen too. Sometimes genetic changes occur just by random chance, not because they help or hurt. These random shifts are called genetic drift, and they can change what traits are common in a population over time.

Fit survives and thrives. When creatures are well-adapted to their home, they live longer and have more offspring who inherit those same advantages. This means the best-adapted traits spread through a population naturally.