Transcript 15-1 History of Evol Thought

CHAPTER 15-1, THE HISTORY OF
REVOLUTIONARY THOUGHT
VOCABULARY
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Evolution- A heritable change in the characteristics within
a population from one generation to the next: the
development of new types of organisms from preexisting types of
organisms over time.
Strata- Layers of rock.
Natural Selection- The process by which individuals that
are better adapted to their environment survive and
reproduce more successfully than less well adapted
individuals do: a theory to explain the mechanism of evolution.
Adaptation- The process of becoming adapted to an
environment: an anatomical, physiological, or behavioral trait
that improves an organism’s ability to survive and reproduce.
Fitness- In evolutionary theory, a measure of an
individual’s hereditary contribution to the next
generation.
DARWIN’S TIME
Charles Darwin (1809-1882) visited the
Galapagos Islands and was curious about how
evolution changed the animals on each island.
 Began theory which other scientists failed to
prove previously about evolution.
 Before Darwin, people thought the Earth was
only thousands of years old and that animals
were unchanging.
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GEOLOGY (CUVIER AND LYELL)
Georges Cuvier (1769-1832) studied the fossils of
organisms in the strata by reconstructing them.
 The older the strata layer, the more different the
organism from present-day organisms.
 Catastrophism: sudden geologic catastrophes
caused the extinction of large groups of
organisms in the past.
 Charles Lyell (1797-1875), an English scientist
 Uniformitarianism: Lyell’s idea that the
Earth’s geologic processes from the past work in
the same way today.
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LAMARCK’S IDEAS
Jean Baptiste Lamarck (1744-1829) had theories
of evolution.
 Living organisms arose from nonliving matter.
 Simple organisms evolve into complicated
organisms.
 Inheritance of acquired characteristics:
individuals could acquire traits during their
lifetimes as a result of experience or behavior,
then could pass those traits onto offspring.
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Inheritance of
Acquired
Characteristics
Offspring
DESCENT WITH MODIFICATION
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Darwin and Alfred Russel Wallace (1823-1913)
created a new theory of “descent with
modification”.
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Every species descended from a preexisting one and
changes over time.
NATURAL SELECTION
FITNESS
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An organism has a high fitness (in evolutionary
terms) if it reproduces more successfully than
other individuals.
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