Changes Over Time
5-1 Darwin’s Voyage
pages 146-156
Changes Over Time - Darwin’s Theory
Darwin’s Voyage
Charles Darwin sailed on the Beagle, from England to the
Galápagos Islands.
Changes Over Time
EVOLUTION
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Map of the Galapagos Island
Link
Changes Over Time
species
p 147
a group of similar
organisms whose
members can mate with
one another and
produce fertile offspring
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species
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page 148, figure 2
What difference in the environment
do you think might explain the
difference in color between the two
species of iguanas?
Changes Over Time
adaptation
p 149
a characteristic that
helps an organism
survive in its
environment or
reproduce
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adaptation
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ADAPTATIONS: Organisms in their
Environment
link
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adaptation
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EVOLUTION
EVOLUTION
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page 149, figure 3
What are some other ways
these birds might be similar or
different that you cannot
observe visually?
Changes Over Time
Darwin's Dangerous Idea
Link
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Darwin’s Discoveries Video
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evolution
p 149
the gradual
change in a
species over time
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evolution
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scientific theory
p 149
a well-tested concept
that explains a wide
range of observations
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scientific theory
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Great Transformations
LINK
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natural selection p 150
the process by which individuals
that are better adapted to their
environment are more likely to
survive and reproduce than
other members of the same
species
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natural selection p 150
“survival of
the fittest”
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natural selection
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EVOLUTION
EVOLUTION
Changes Over Time - Darwin’s Theory
Overproduction and Variation
Natural selection is the process by which individuals who are
better adapted to their environment are more likely to survive
and reproduce than other members of the same species.
Changes Over Time - Darwin’s Theory
Competition and Selection
Variations among turtles make some of them better able to
survive. Turtles that survive to become adults will be able to
reproduce.
Changes Over Time - Darwin’s Theory
Relating Cause and Effect
In a graphic organizer, identify factors that cause natural
selection.
Causes
Overproduction: More offspring are
produced than can survive.
Variations: Members of the same
species differ.
Competition: Offspring compete for
survival.
Selection: Some variations make
individuals better fit for survival.
Environmental Change: Changes can
affect an individual’s survival.( p 154, fig.6)
Genes: Genes that help determine survival
are passed from parent to offspring.
Effect
Natural Selection
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natural selection
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VIDEO: How does evolution work?
LINK
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VIDEO: Evolution of camouflage
LINK
Changes Over Time
variation p 151
any difference
between individuals
of the same species
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variation
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Extinction: When Species Die
LINK
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Theory of Evolution
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Video:
Why does evolution matter
now?
Link
Changes Over Time
End of Section:
Darwin’s Theory
Changes Over Time - Evidence of Evolution
Homologous Structures p166
The structure of the bones in a dolphin’s flipper, a bird’s
wing, and a dog’s leg is similar. Homologous bones are
shown in the same color.
Changes Over Time - Evidence of Evolution
A Branching Tree
This branching tree shows how scientists now think that
raccoons, lesser pandas, giant pandas, and bears are
related.
Changes Over Time - Evidence of Evolution
Kaibab and Abert’s Squirrels
These two kinds of squirrels have
been isolated from one another
for a long time. Eventually this
isolation may result in two
different species.
Changes Over Time - Evidence of Evolution
Identifying Supporting Evidence
Evidence consists of facts that can be confirmed by testing or
observation. As you read, identify the evidence that supports
the theory of evolution. Write the evidence in a graphic
organizer like the one below.
Evidence
Fossils show that organisms that
lived in the past were very different
from organisms alive today.
Theory
Evolution
Patterns of early development
show that some different
organisms look similar during their
early stages.
Similar body
structures in different species
show that the organisms shared
a common ancestor.
Changes Over Time
End of Section:
Evidence of
Evolution
Changes Over Time - The Fossil Record
How Do Fossils Form?
Most fossils form when organisms that die become buried in
sediments.
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fossil formation
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Graphic Organizer
Fossil Formation
An organism dies in water.
The organism is buried under sediment.
Over millions of years, the sediments harden and become rock, and the
hard parts of the organism are replaced by minerals.
The fossil becomes exposed on the surface of a rock.
Changes Over Time
Why no internal organs?
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REVIEW: fossil formation
Changes Over Time - The Fossil Record
Earth’s History as a Clock
Fossils found in rock layers tell the history of life on Earth.
The history of life can be compared to 12 hours on a clock.
Changes Over Time
What is the geologic time scale?
Changes Over Time - The Fossil Record
Precambrian Time and the Paleozoic Era p162-163
Changes Over Time - The Fossil Record
Mesozoic and Cenozoic Eras
Changes Over Time - The Fossil Record
Building Vocabulary
After you read the section, write a definition of each Key
Term in your own words.
Key Terms:
petrified fossil
radioactive
punctuated
element
equilibria
mold
half-life
cast
fossil record
relative dating
extinct
radioactive
gradualism dating
Examples:
Fossils
The
rocks
theory
thatthat
of
form
punctuated
fossils
by minerals
are found
equilibria
replacing
near contain
accounts
remainsfor
arethe
calledinpetrified
radioactive
gaps
the fossil
elements,
fossils.
record.which are unstable elements
that decay, or break down, into different elements.
A hollow space in the sediment in the shape of an
The
half-life
of a of
radioactive
element
is the
time it
organism
or part
an organism
is called
a mold.
takes for half of the atoms in a sample to decay.
A cast is a copy of the shape of the organism that
The
mademillions
a mold.of fossils that scientists have collected are
called the fossil record.
Scientists use relative dating to determine which of
A
species
two
fossilsisisextinct
older. if no members of that species are
still alive.
A
technique called
radioactive
dating
allowsslowly but
Gradualism
proposes
that evolution
occurs
scientists
steadily. to determine the actual age of fossils.
Changes Over Time
End of Section:
The Fossil
Record
Changes Over Time
Evolution
link
Changes Over Time
evolution of the elephant