QUESTION …How do the small changes shown by fossil evidence come
about…WHY DOES EVOLUTION HAPPEN?
THEORY…Charles Darwin believed that evolution occurs because of the
basic process of NATURAL SELECTION
1.
Living organisms overproduce:
_________________________________________________________
Other examples:
Spiders
Turtles
2. There are not enough resources for all of these overproduced offspring, so the organisms begin to compete
in a struggle
for survival.
a.
Each organism will need to find:
1.
2.
3.
4.
3. There is Variation among the offspring:
___________________________________________________
Q - What are the two causes of variation in living things?
________________________ and _________________________
Q – How can variation affect evolution?
A. ___________________________________ makes certain that variation occurs because the formation of
gametes ( __________ and __________ ) the process of _________________ shuffles the genes. If these inherited
traits help an individual live/survive it will be able to reproduce and pass those genes on to future generations.
B. _________________________ can affect evolution if they occur in _______________ . Other examples
of _____________________ that don’t affect evolution ….
4.
Survival of the fittest - Those organisms that are best adapted to a particular environment will be able
to survive long enough to __________________________.
a. This assures that positive traits (_____________________) are passed on to future generation and the
species evolves over time. This evolution occurs with small changes over time…little by little.