NATURAL SELECTION

ON THE ORIGIN OF SPECIES Darwin delayed publishing for over 25 years (largely due to social influences)

He left out his hypotheses about human evolution.

Darwin proposed “Natural Selection” and “Survival of the Fittest”

His theories form the current basis for evolution and the study of biological science

ARTIFICIAL SELECTION

NATURAL SELECTION1. Competition for resources – food, space,

mates

NATURAL SELECTION2. Survival of the fittest – variations within genes

may provide some organisms with an advantage over others

“The individual best suited to their environment will survive to reproduce.”

Ex – camouflage, mimicry, efficiency of photosynthesis, hunting in packs.

Over time, the population changes due to the frequency of inherited traits.

Real Life Scenario: Industrial revolution increases pollution in the air. The pollution can be seen discoloring the environment. Peppered moths saw a big change in favored color.

Before Industrial Revolution After

MISCO

NCEPTIO

NS

Bigger and stronger is not always better!

4 COMPONENTS OF NATURAL SELECTION

1. Natural Variation in DNA. 

2. DNA is inherited. 

3. More individuals are born than can survive (struggle for existence).

4. Variable “fitness” leads to the best suited organisms surviving to reproduce.

THE END