The inheritance of acquired characteristics is a theory that physiological changes acquired during an organism's lifetime can be passed down to the offspring.
It is also known as adaptation theory, and its sometimes confused with Lamarckism, the evolutionary theory of French naturalist Jean-Baptiste Lamarck.
The elongated neck of the giraffe is a classical example to explain the theory of acquired characteristics.
According to Lamarck's theory, a giraffe's neck could elongate over a lifetime of straining to reach high branches.
The elongated neck of the giraffe which is an acquired trait is then inherited from one generation to another.
