Chapter 16:
Darwin’s Theory of Evolution
Chapter 16.1 (Pg 450-453):
Darwin’s Voyage of Discovery
Darwin’s Journey
- Born in England on February 12, 1809
- View of the world changing during this time
- Traveled around the world aboard the
HMS Beagle for 5 years
- Collected plant and animal specimens
which led him to many conclusions
about ancient world
Darwin’s Observations
- Discovered many different species
- Made observations about species’
characteristics and habitats
- Observed three patterns of diversity:
1) Species vary globally
2) Species vary locally
3) Species vary over time
Species Vary Globally
- Different species that are ecologically similar
inhabit separated, but ecologically similar,
habitats around the globe
- Species with similar characteristics live in
different parts of the world
- Some species only found in one
part of the world
- Lemurs in Madagascar
- Kangaroos in Africa
Ostrich
Emu
Rhea
How do you explain these patterns?
Species Vary Locally
- Different species that are related often occupy different habitats in a
local area
- Galapagos Tortoises
- Shells differ from
island to island
- Bird beaks differ
on each island
Species Vary Over Time
- Darwin also collected fossils,
preserved remains of ancient
organisms
- Noticed that some fossils of extinct
animals were similar to living
species from the same area
Darwin’s Theory of Biological Evolution
- Suggested that species are not fixed but
could change by some natural process
- Explains how modern organisms evolved
over long periods of time through descent
from common ancestors