Lamarckism
Lamarckism is an old, outdated idea about evolution that scientists used to believe in a long time ago. It was named after a man named Jean-Baptiste Lamarck who thought that if an animal needed a certain trait to survive, like longer necks to reach leaves on high branches, they could develop that trait during their lifetime and pass it on to their babies.
For example, if a giraffe stretched its neck a lot during its lifetime to reach the high leaves, it would end up with a longer neck. And when it had babies, they would inherit that longer neck from their parents. This is not true, because your DNA and your body are two different things.
However, we now know that this idea is wrong. We now know that traits are not acquired through use, so your body can't change because of what you do during your lifetime. Evolution is caused by a different process: The animals that are better suited to their environment are more likely to survive and have babies, and their babies will inherit traits that help them survive too. Over time, animals with helpful traits prosper and the ones that don't die off. That's called natural selection.
For example, if a giraffe stretched its neck a lot during its lifetime to reach the high leaves, it would end up with a longer neck. And when it had babies, they would inherit that longer neck from their parents. This is not true, because your DNA and your body are two different things.
However, we now know that this idea is wrong. We now know that traits are not acquired through use, so your body can't change because of what you do during your lifetime. Evolution is caused by a different process: The animals that are better suited to their environment are more likely to survive and have babies, and their babies will inherit traits that help them survive too. Over time, animals with helpful traits prosper and the ones that don't die off. That's called natural selection.