Evolution and Natural Selection
How do Species Change and Diverge Over Time?
Adaptations: _________________________________________________________________
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Charles Darwin (1809 - 1882):
-​ An English naturalist who studied variations in plants, animals, and even fossils
-​ Famous for his theory of evolution, suggesting that the organisms that survive are
those that adapt best to their environment
-​ In September 1835, he visited the Galápagos Island, a chain of islands in the eastern
Pacific Ocean. There, he made detailed notes and observations on plants and animals.
Some of his observations include:
-​ There was variation between members of the same species.
-​ Some members of a species were better suited to the environment than others.
Among his best-known animal specimens are the finches. He observed different types of
finches, with each island hosting a distinct species. These species exhibit varying beak sizes
and shapes, which are adaptations to their respective primary food sources.
What is Natural Selection?
-​ Every species contains __________________, and individuals best ________________
to the environment survive.
-​ They are also more likely to survive long enough to _____________________________,
passing their ‘successful’ genes on to the next _______________________.
-​ Natural selection is the engine that drives evolution.
Evolution: _________________________________________________________________
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It happens ____________ and _____________________ due to natural selection.
However, larger-scale changes can be _______________ by extreme events such as
earthquakes, a new predator, a new disease or a physical separation such as a
mountain rising up or a land mass breaking apart.
Does evolution occur in other organisms besides animals? Below, list some examples:
Variation: _________________________________________________________________
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*Variation is mainly the result of genetic differences and mutations
Directional Selection: ________________________________________________________
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Example and Explanation:
Stabilizing Selection: ________________________________________________________
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Example and Explanation:
Disruptive Selection: ________________________________________________________
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Example and Explanation: