Transcript 15.1 The Puzzle of Life`s Diversity

What is evolution?
• Change over time
– DNA – mutations
• Genes and mutations that are beneficial are
passed on to offspring
– Goal of all living things: pass genes on to another
generation
• What if a gene causes a bad mutation?
15.1 The Puzzle of Life’s Diversity
Definitions
• Evolution:
– Change over time
– The process by which modern organisms have
descended from ancient organisms
• Theory:
– Well-supported testable explanation of phenomena
that occur in the natural world
Voyage of the Beagle
• Charles Darwin
– Born in England,
1809
– Boarded the Beagle
in 1831 for it’s
journey around the
world
Charles Darwin
• Made observations and collected evidence
• Kept detailed notes and brought specimens
home to study back in England
• Proposed a hypothesis about how life changes
over time
The Voyage of the Beagle
Darwin’s Observations
• Patterns of Diversity
– Darwin noticed that organisms living in different
habitats and environments had very different traits
– And…similar environments had organisms with
similar traits
Darwin’s Observations
• Living Organisms and
Fossils
– Darwin collected fossils
and compared them to
animals alive today
Darwin’s Observations
• The Galapagos Islands
– Located off the coast of
Ecuador
– The islands are close
together, but the climates
on them are different
– Animals living on these
islands were different
depending on the
environment
Darwin’s Observations
• Darwin studied finches from the Galapagos
– Found that they differed from island to island
– Realized that each different species evolved from
an original South American ancestor