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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
Changes Over TimeMap of the Galapagos Island
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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?
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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
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adaptation
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EVOLUTIONEVOLUTION
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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?
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Darwin's Dangerous Idea
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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
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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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EVOLUTIONEVOLUTION
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.
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Relating Cause and EffectIn a graphic organizer, identify factors that cause natural selection.
Natural Selection
Overproduction: More offspring are produced than can survive.
Causes
Effect
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.
- Darwin’s Theory
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natural selection
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VIDEO: How does evolution work?
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VIDEO: Evolution of camouflage
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variation p 151
any difference between individuals of the same species
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variation
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Extinction: When Species Die
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Theory of Evolution
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Video: Why does evolution matter now?
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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.
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Identifying Supporting EvidenceEvidence 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.
Evolution
Fossils show that organisms that lived in the past were very different
from organisms alive today.
Patterns of early development show that some different
organisms look similar during their early stages.
Similar bodystructures in different species
show that the organisms shareda common ancestor.
Theory
Evidence
- Evidence of Evolution
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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
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.
Fossil Formation
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Why no internal organs?
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REVIEW: fossil formation
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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.
- The Fossil Record
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What is the geologic time scale?
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Precambrian Time and the Paleozoic Era p162-163
- The Fossil Record
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Mesozoic and Cenozoic Eras
- The Fossil Record
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Building VocabularyAfter you read the section, write a definition of each Key Term in your own words.
- The Fossil Record
Key Terms: Examples:
petrified fossil Fossils that form by minerals replacing remains are called petrified fossils.
mold A hollow space in the sediment in the shape of an organism or part of an organism is called a mold.
cast A cast is a copy of the shape of the organism that made a mold.
relative dating Scientists use relative dating to determine which of two fossils is older.
radioactive dating A technique called radioactive dating allows scientists to determine the actual age of fossils.
Key Terms: Examples:
radioactive element
half-life
fossil record
extinct
gradualism
The rocks that fossils are found near contain radioactive elements, which are unstable elements that decay, or break down, into different elements.
The half-life of a radioactive element is the time it takes for half of the atoms in a sample to decay.
The millions of fossils that scientists have collected are called the fossil record.
A species is extinct if no members of that species are still alive.
Gradualism proposes that evolution occurs slowly but steadily.
Key Terms: Examples:
punctuated equilibria The theory of punctuated equilibria accounts for the gaps in the fossil record.
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End of Section:The Fossil
Record
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Evolution
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evolution of the elephant
