1. Darwin’s Observations
Section 10.2
Darwin’s Observations

2. Darwin observed variation among island species
Variation  the difference in the physical traits of an individual from those of other individuals in the group to which it belongs
Examples include tortoises:
Saddle-backed tortoises that have long necks live in areas with a lot of tall plants
Domed tortoises that have shorter necks and legs live in wet areas rich in mosses and shorter plants

3. Examples of Finches:
Finches with strong, thick beaks live in areas with a lot of large, hard-shelled nuts
Finches with more delicate beaks live in areas where insects or fruits are widely available

4. Darwin realized species could adapt to their environment
Adaptation  a feature that allows an organism to better survive in its environment
Can lead to genetic change in a population over time

5. Darwin observed fossil and geologic evidence of an ancient Earth
Fossil evidence included:
Darwin found fossils of huge animals such as a giant armadillo
These fossils looked like living species suggesting that modern animals might have some relationship to fossil forms
Geologic evidence included:
Darwin also found fossils of marine animals high up in the Andes mountains
This suggested that land that had been underwater was moved above sea level, possibly from an earthquake