Figure 7.9: Four of Darwin’s finch species from the Galápagos Islands. The birds came
from the same finch ancestor. They evolved as they adapted to different food resources on
different islands. The first bird uses its large beak to crack open and eat large seeds. Bird
#3 is able to pull small seeds out of small spaces. ( 31 )
Return to England
When Darwin returned to England five years later, he did not rush to announce his discover-
ies. Unlike other naturalists before him, Darwin did not want to present any ideas unless he
had strong evidence supporting them. Instead, once Darwin returned to England, he spent
over twenty years examining specimens, talking with other scientists and collecting more
information before he presented his theories. Darwin’s observations eventually resulted in
the Theory of Evolution by Natural Selection. His now famous book,The Origin of Species
is a diary of his explorations and discussion on how he interpreted his observations (Figure
7.10).
Other Influences on Darwin
How did Darwin come up with his theories? Some of Darwin’s idea conflicted with widely
held beliefs, included those from religious leaders, such as:
- All organisms never change and never go extinct, they are fixed.
- The world is only about 6,000 years old.
It was because of these widely held beliefs that delayed Darwin from presenting his findings.
Charles Darwin was influenced by the ideas from several people.
Before his voyage on the Beagle: