Darwins Dilemma

            
             A)Darwin set sail on December 27, 1831 for a cruise around the world.
             1)He was well educated and had a strong interest in natural history.
             2)He also had keen powers of observation and an analytical mind.
             3)Each place he went he collected animal and plant specimens to his collection.
             (a)He examined his specimens and filled notebooks with his observations.
             B)Throughout the voyage he witnessed countless wonders of nature.
             1)He demanded explanations for these wonders.
             II)The Diversity of Life.
             A)When Darwin visited tropical South America he saw countless species.
             1)In one Brazilian forest he collected 68 different species of beetles.
             2)This was amazing because he wasn't specifically looking for beetles.
             B)Scientists now estimate that there are as many as 10 million species alive today.
             C)When Darwin traveled he found evidence of organisms that have vanished from the earth.
             1)Scientists estimate that more than 99.9% of the species that were alive are now extinct.
             2)That means that several hundred million species have become extinct.
             III)Fitness: To Survive and Reproduce.
             A)Darwin was impressed by the many different ways in which organisms survive.
             B)He noted that most animals and plants seem well designed to do what they do.
             C)The combination of physical traits and behaviors that helps organisms survive and reproduce in their environment is what Darwin called fitness.
             D)Darwin wrote The Origin of Species by Means of Natural Selection.
             1)He wrote that modern organisms have been produced through evolution.
             (a)Evolution is a slow process of change in species over time.
             2)He argued that each species has descended from other species over time.
             3)He said that if you looked back far enough you will see that all species have common ancestors.
             (a)He called this principal common descent.
             4)He also argued that fitness arises through adaptation.
             E)Successful adaptations enable organisms to be better suited to their environment.
             1)He also used adaptation to describe any characteristic that increases an organisms fitness for survival.