Teori Lamark

This theory is based on the inheritance of acquired character  which are defined as the changes (variation) developed from normal in response to changes of environment.

1.      New needs

The changes in the environmental factors lead to new needs in the living organism. To fullfil the new needs, organism have to exert special effort like change habit or behavior.

2.      Use and Disuse organ

New habit lead to greater use of certain organ. This use and disuse organs greatly affect the form, structure and function of organs. Extra use of organ make them more efficient while disuse lead to degeneration and ultimate disappear.

3.      Inheritance of acquired inherintance

Are inheritable and transmitted to offspring so that these are born fit to face the changed environmental condition and the changes of their survival are increase. The inheritance of acquired characteristics is a hypothesis that physiological changes acquired over the life of an organism (such as the enlargement of a muscle through repeated use) may be transmitted to offspring

4.      Speciation

Every generation, new character are acquired and transmitted to generation, so that new character acumulate. After a number of generation, a new species is formed. Modification developed by animal during their own lifetime are inheritable and acumulate over a period of time resulting new species.

The Critism of Lamark's theory

"the environmental factors effect only somatic cells and not germ cell". 

=> Breeding of mutilated tail mice for 22 generation  but tailless mice were never born. It means phenotypic change do not result in genetic change that can be passed on to the next generation