Bio-Pac 07: Objective 05-07

Question 1

Objective 5. State Lamarck’s theory of evolution.

Answer 1

Jean Lamarck believed that the environment was key to evolution. He had three parts to his theory of evolution. The first is the theory of need, which states organisms change because of an inner need to change. The second was the theory of use and disuse, which believed organs remain active and strong when used and disappear when not used. The third part is the theory of acquired traits which states traits “acquired” during a lifetime can be passed on to the offspring.

Question 2

Objective 6. Summarize Darwin’s theory of natural selection.

Answer 2

Charles Darwin’s theory of evolution explains how and why species develop during evolution. This theory has five steps. The first says all organisms produce more offspring then can actually survive. The second step says every organism struggles to survive. The third says individuals of a given species vary. (Individuals of a given species vary because of the environment.) The fourth step says that individuals best adapted to the environment will survive, in other words the survival of the fittest. The fifth step says that organisms that survive pass their traits on to their offspring.

Question 3

Objective 7. Describe how variations occur in species.

Answer 3

Organic variation has nothing to do with need. Organisms vary no matter what because of DNA. Whether a variation is helpful or harmful depends on the environment.