Download 10.2 Darwin`s Observations

10.2 Darwin’s Observations
KEY CONCEPT
Darwin’s voyage provided insight on evolution.
10.2 Darwin’s Observations
Early scientists proposed ideas about evolution.
• Evolution is the biological change process by which
descendants come to differ from their ancestors.
• A species is a group of organisms that can reproduce
and have fertile offspring.
These scientists included:
• Linnaeus
•Lamarck
•Darwin (we’ll focus here)
10.2 Darwin’s Observations
Darwin observed differences among island species.
• Variation is the difference in a physical trait between individuals .
– Galápagos saddle backed tortoises that live in areas with tall
plants have long necks and legs.
– Domed tortoises that live in wet areas with short plants have
shorter necks and legs.
10.2 Darwin’s Observations
Darwin observed differences among island species.
• Finches are another example.
– Finches with strong, thick beaks live in areas with a lot of
large, hard shell nuts.
– Finches with delicate beaks live in areas where small
insects and fruits are readily available.
10.2 Darwin’s Observations
• An adaptation is a feature that allows an organism to better
survive in its environment.
– Species are able to adapt to their
environment.
– Adaptations can lead to genetic
change in a population.
10.2 Darwin’s Observations
Darwin observed fossil and geologic evidence supporting
an ancient Earth.
• Fossil evidence included:
• Darwin found fossils of extinct animals that resemble modern
animals. (ex: Glyptodon- a giant extinct armadillo, resembled
modern armadillos)
• Darwin found fossil shells from
marine organisms high up in the
Andes mountains.