Download U6-Topic1_Developing a theory

Grade 11A
Name:______________________________ Class: _________________
Active reading 11A – Evolution by natural selection
Topic 1: Developing a theory
How did Darwin’s experiences influence his ideas about evolution?
Evolution is the process by which species change over time. Modern evolutionary
theory began when Charles Darwin presented evidence that evolution happens
and gave an explanation of how it happens.
The VOYAGE OF THE BEAGLE
In the 1830s, Darwin took a global
voyage on a ship called the Beagle.
This voyage inspired many of his
ideas. During the voyage, Darwin
collected many natural objects,
including nine species of finches in
the Galapagos Islands. The birds
were very similar, but their beaks
differed in size and shape. He also
noted that many of the island’s plant
and animal species were similar to
species in South America.
Darwin proposed that the finch
species descended from a single South American species. The descendants
became modified, or changed, over time to survive on different foods. Darwin
called such a change descent with modification. This idea was a key part of his
history. After he returned from his voyage, Darwin studied his data for years. He
did not report his ideas about evolution right way. Instead, he took time to gather
more data and to form a good explanation for how evolution happens.
Grade 11A
Name:______________________________ Class: _________________
ARTIFICIAL SELECTION
Later in his life, Darwin became interested in breeding exotic pigeons. He noted
that breeders take advantage of natural variations within a species. Breeders
identify traits in each generation that they prefer. For example, a dog breeder
may prefer a dog with thicker fur or longer legs. If these traits can be inherited,
breeders can simply select individuals that have the traits. Darwin called this
process artificial selection.
How did the ideas of others influence Darwin?
Most people in Darwin’s time thought that species stayed the same forever.
However, some scientists proposed ways that species may change over time.
Darwin was influenced by ideas from the fields of natural history, economics, and
geology.
Individuals and ideas that influenced Darwin
Individual(s)
Major ideas
and field
Jean Baptiste
 Proposed that organisms change
Lamark (natural
over time as they adapt to
history)
changing environments
 Though (incorrectly) that changes
due to use or disuse of a trait
would be passed on to offspring
Thomas
 Noted that the human
Malthus
population was growing faster
(economics)
than the food supply
 Predicted that limited resources
would cause deaths from
disease, war, or famine
Georges Cuvier Argued that fossils in rock layers
(geology)
showed:
 Differences in species over time
 That species from the past
differed from those of the
present
James Hutton
Thought that geologic processes, such as
and Charles
those that form rocks and fossils, work
Lyell (geology)
gradually and constantly
Importance to Darwin’s theory
Suggested that inheritance plays
a role in evolution
Darwin proposed that all
populations, not just human
populations, are limited by their
environments.
Showed that species change over
time
Showed that earth’s history was
long enough for species to have
evolved gradually
Grade 11A
Name:______________________________ Class: _________________
Key words
Evolution
Descendant
Artificial selection
Finches
Trait
Species
Vocabulary
Artificial selection The human practice of breeding animals or plants that have
certain desired traits.
Evolution generally, in biology, the process of change by which new species
develop from preexisting species over time; at the genetic level, the process in
which inherited characteristics within populations change over time; the process
defined by Darwin as ‘’descent with modification’’
A. Write one or more sentences to answer the following questions
1. How did Darwin explain the similarities among finches in the Galapagos
Islands and in South America?
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2. Explain according to Darwin, why did the different populations of finches
become modified over time?
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3. What is descent with modification?
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Grade 11A
Name:______________________________ Class: _________________
4. How does artificial selection provide evidence that species can change over
time?
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5. Identify what idea did Lamarck and Darwin share?
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6. What evidence from fossils and rock layers influenced Darwin’s ideas?
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7. What idea of Malthus did Darwin extend to all populations?
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8. Identify three fields of study that influenced Darwin’s ideas?
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Grade 11A
Name:______________________________ Class: _________________
B. Circle the letter of the phrase that best answers the question.
1. Prior to the 1800's people believed _____.
A)
B)
C)
D)
The earth was billions of years old
Living things shared a common ancestor
Species were specially created and fixed in time
Species evolved in response to their environment
2. Darwin made some of his most famous observations of species'
adaptations on the _____ Islands.
A)
B)
C)
D)
Virgin
Galapagos
Falkland
Philippines
3. All the ground-dwelling finches that live on the Galapagos Islands have
the same size and shape beaks.
A)
B)
True
False
4. According to Darwin’s descent with modification, organisms …
A)
B)
C)
D)
Can exist in only one particular geographic location
Give rise to similar organisms
Do not change over time
Both (a) and (b)
C. What does Islam say about evolution? What is the Islamic view on
evolution?
Search the internet or discuss with your Islamic teacher
Grade 11A
Name:______________________________ Class: _________________
D. The illustration below show a South American finch and some of the
species of finches found on Galapagos Islands. The map shows the
relationship of the Galapagos Islands to the west coast of South America.
There are 13 species of finches found on the Galapagos Islands. These finches
have a wide variety of food sources and beak shapes. There is one genetically
similar species of finch found on the South American mainland. This finch eats
small seeds.
Use the map and the bird illustrations to identify and explain two ways that
these finches provide evidence that supports the theory of evolution.
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