What does Lamarckism idea of "acquired traits" propose?

According to Lamarckism, characteristics acquired by parents during development will be directly transferred to their children.

In its most basic form, this would imply that any child fathered by a weightlifter would inherit the muscular mass acquired through weight training.

Lamarckism uses the example that giraffes' offspring would have longer necks at birth because the animals had to extend their necks upward to feed on the leaves of taller Eucalyptus trees.

This made evolution fit within Archbishop Usher's timeline for the evolution of life on Earth, starting in 4004 BC, by allowing traits to change in each subsequent generation.

Lamarckism proposes that organisms can pass on traits acquired during their lifetime to their offspring. This suggests that characteristics acquired through use or disuse of organs can be inherited by subsequent generations.