Natural Selection

Prologue BSCS

Evolution -

evidence for -

Scientists explained that evidence differently

Lamark - environment provided a need for the individuals of a species to change. They did so according to two laws/principles

use and disuse -

acquired traits are inheritable -

Experimental data does not support his second assumption, acquired traits are not inheritable,* therefore his entire hypothesis is invalid.

Charles Darwin - Natural Selection

1. Organisms within a species are not created/born identical, there are genetic variations and these variations are inheritable.

2. More organisms are born than the

3. Not all the of the population can survive, there will be

4. If an organism’s variation gives it an advantage in that environment (adaptation), then it will increase this organisms chance to survive and reproduce, passing on that adaptation. Not a guarantee of survival, only an increased chance for survival! Sometimes this is called the “survival of “

5. When these adaptations accumulate in the population as time goes on. The species will evolve or ___________________________. All experimental data to date, supports Darwin’s hypothesis. It is considered a __________________________.

Key idea to remember:

Variations are

Adaptations are