What were Lamarck’s ideas about evolution and why were those ideas incorrect?

Lamark suggested that organisms can acquire traits which benefit them without any genetic means. He suggested that a change was gradually introduced into organisms of a species during their lifetime and this change could then be seen in the offsprings.

This idea was wrong because an organisms characteristics cannot change in his lifetime.

The theory of Lamarck's inheritance can be disregarded by our knowledge about hereditary genetics.