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Evolution Notes
Darwin’s Theory
•__Charles Darwin_____________________ (English) set sail around the world on the HMS
Beagle_____________ in December 1831.
• He was a naturalist____________________________________ and wanted to learn about the living things in
the world.
•The diverse animals and plants he saw lead him to create the __theory of Evolution by natural
selection____________________________________
Darwin’s Observations
He stopped in South America, and then went to the Galapagos Islands_____________ ______
• He observed these three pieces of evidence to form his hypothesis:
1. The _diversity of living things
2. The _fossilized_______ remains of ancient organisms
3. Characteristics of life on the _Galapagos Islands______ ______ compared to the rest of the world.
Comparing the characteristics of the organisms on the Galapagos Islands to the South American organisms
•Many birds and plants on the islands were like those on the mainland.
•Iguanas_____________ on the island____________ had __larger claws________________ to grip rocks.
Iguanas_____________ on mainland__________________ had smaller claws___________________ to climb
trees.
•Darwin hypothesized that a small number of animals were blown_____ or drifted_____ from the mainland
to the islands.
•Then those animals___________________ reproduced and slowly become
different_____________________________ from their mainland relatives.
Examples of Comparisons Among the Island Organisms
•Differences in finches’ beaks.
oFinches that ate worms_____ had slender________ beaks
oFinches that ate seeds_______ had strong____, wide_____ beaks
•Adaptation: an inheritable_________ trait that increases an organism’s _fitness_____ in their environment.
•Fitness: how well an organism’s _trait__allows it to survive______ and reproduce______ in its
_enviorment____
Evolution
