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Chapter 10 “Natural
Selection”
10.1 “A Riddle:
Life’s Diversity and
Connections”.
 Section
 Objectives:
Define Evolution.
• Describe Darwin’s
contributions to science.
Introduction to Evolution
 1.
Charles Darwin believed
that humans evolved from
monkeys.
 2. Darwin went to the
Galapagos Islands on vacation.
 3. Evolution is a gradual
change over time.
Cont…..
 4.
If I cut off my arm 50% of
my offspring (children) will
have only one arm.
 Inferior males get all the
girls.
Voyage of the Beagle
 Charles
Darwin:
contributed to our
understanding of
Evolution.
 Set sail on the Beagle (a
research ship) in 1831.
Observations
 Studied
the “natural” world.
 Noticed diversity in his
travels.
 Species observed were well
suited to whatever
environment they inhabited.
 Collected fossils that
resembled sp. living today.
Galapagos Islands
 Influenced
Darwin the
most.
 Small group of islands west
of South America.
 Paid attention mostly to
giant tortoises, marine
iguanas, and finches.
Continued….
 Collected
specimens
throughout his voyage and
studied comparisons.
 Began asking Q’s about the
different species.
 Fitness = the ability to
survive and reproduce.
Structures
 Discoveries
made by
researchers at the time.
 Homologous Structures =
developed from similar tissues
at early stages of life.
 Vestigial Organs = structures
that have little or no obvious
purpose.
Today’s Assignment
 Complete Worksheet
10.1
“Darwin’s Solutions”
Section 10-2
 Objective:
• Explain what is meant by the
term artificial selection.
• Explain Evolution by
Natural Selection.
Darwin’s Findings
 Great
adventure and
turning point within the
scientific community.
 Galapagos Island species
vs. Mainland species.
The Finches
(page 227, fig. 10-11)
 Darwin
thought they were
different species.
 Why do they have different
shaped beaks?
 Why would each island have
different variations of the
same bird?
Darwin’s Book
 In
1844 Darwin wrote most
of his ideas.
 In 1859 (30 years later), he
published his findings in
the Origin of Species.
“Origin of Species”
 Caused
mass hysteria in the
community.
 Supported the idea that life
has changed, or evolved over
time.
 Proposed a hypothesis to
explain how evolution works.
Breeding (page 228, 10-12)
 Selective breeding =
producing a new generation by
mating individuals with desired
characteristics.
 Artificial breeding = nature
provided the variation among
different organisms, and humans
selected those variations they
found.
Natural Selection
 In
nature, selective
pressures decide who will
survive and reproduce.
 The “struggle for
existence”selects the fittest
individuals to survive in
nature.