Flashcards in Theories Deck (11)
name 4 postulates of Lamarckism
1. Theory of elan vitae or growth
2. Theory of environment pressure needs and spontaneous formation of organs
3. theory of use and disuse
4. Theory of Inheritance of acquired characters
Theory of elan vitae or growth
The internal forces of life tend to increase the size of an organism by growth and systems.
Theory of environment pressure need and spontaneous formation of organs
New organs and systems are formed because of need or want which has arisen due to continuous environment pressure on the organism
Change in environment can bring change in organs.
Infertile and fertile soil relation to plant growth.
Theory of use or disuse
The development of an organ is directly proportional to its use; continuous use strengthen the organ while disuse weakens it.
Theory of inheritance of acquired characters
all the changes in organisms acquired during life time are transmitted to the next generation k/a inheritance of acquired characters
Mechanism of lamarckism
Critics of Theory of elan vitae or growth
often evolution proceeded without increase in size rather reduction in size
Many ferns and conifers which became extinct were once a gigantic tree.
Critics of Theory of environment pressure need and spontaneous formation of organs
the desire of man can not lead to formation of new structure.
Many wanted to fly but never got wings.
Critics of Theory of use or disuse
heart is not increasing its size inspite of its continuous use.
Critics of Theory of inheritance of acquired characters
Cutting mice tail for 20 generation to observe length of tail not getting any shorter. means, Acquired characters (mutilated tails) were not inherited.