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Theory A well-supported general idea that
explains a large set of factual patterns and predicts other patterns.
Science The method of inquiry that requires
the generation, testing, and acceptance or rejection of hypotheses.
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The Scientific Method Patterns, Associations, Connections Hypotheses Predictions Observations, Experiments, New
data
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The Evolution of Evolution How did our knowledge of the
history of living organisms move from the realm of belief systems to the realm of science?
How did the scientific evidence for evolution develop?
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How Do We Know That Evolution Has Occurred? The evidence for evolution has
primarily come from four sources: 1. the fossil record of change in
earlier species 2. the chemical and anatomical
similarities of related life forms
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3. the geographic distribution of related species
4. the recorded genetic changes in living organisms over many generations
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The Evolution of Evolution “On the Shoulders of Giants”:
Explaining the Changing Earth Through the work of Hooke, Steno,
Hutton, Smith, and Lyell-- and many others-- the study of the earth shifted from the supernatural to the natural.
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Evolution Change through time; here, with reference to
biological species.
Fossils Remains of life-forms of the past.
Strata Layers; here, the layers of rock and soil under
the earth’s surface.
Stratigraphy The study of the earth’s strata.
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Pre-Darwin theories on evolution The leading biological scientist of the
mid 18th century was the Swedish botanist Karl von Linné (Carolus Linnaeus) 1707-1778. He proposed a logical classification system for all living things which he proposed in his book Systema Naturae, taxonomy.
Jean-Baptiste Lamarck. 1744-1829. He believed that evolution was mostly due to the inheritance of acquired characteristics as creatures adapted to their environments.
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George Cuvier, 1769-1832. He advocated the theory of catastrophism , as did most other leading scientists of his day. Cuvier's explanation relied solely on scientific evidence rather than biblical interpretation.
Charles Lyell , 1797-1875. He documented the fact that the earth must be very old and that it has been subject to the same sort of natural processes in the past that operate today in shaping the land. He provided conclusive evidence for the theory of uniformitarianism
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Darwin and Natural Selection Charles Darwin, 1809-1882
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Darwin identified 13 species of finches in the Galápagos Islands
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Darwin identified 13 species of finches in the Galápagos Islands
He concluded that when the original South American finches reached the islands, they dispersed to different environments where they had to adapt to different conditions
Today we use the term adaptive radiation to refer to this sort of branching evolution in which different populations of a species become reproductively isolated from each other by adapting to different ecological niches and eventually become separate species.
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Darwin came to understand that any population consists of individuals that are all slightly different from one another. Those individuals having a variation that gives them an advantage in staying alive long enough to successfully reproduce are the ones that pass on their traits more frequently to the next generation.
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Darwin did not believe that the environment was producing the variation within the finch populations. He correctly thought that the variation already existed and that nature just selected for the most suitable beak shape and against less useful ones.
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definitions
Catastrophists Those who believe the history of the earth is
explained by a series of global catastrophes, either natural or divine in origin.
Comparative Anatomy Comparing the anatomical features of various
species. Used to reconstruct a fossil species from fragmentary remains.
Uniformitarianism The idea that present-day geological processes can
also explain the history of the earth.
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The Evolution of Evolution “Common Sense At Its Best”:
Explaining Biological Change Charles Darwin was born into a world
that accepted the fact of biological change but was still in search of a mechanism for that change.
Lamarck’s model of inheritance of acquired characteristics applied to the evolution of long necks and tall bodies in giraffes.
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definitions
Adaptation The state in which an organism is
adjusted to and can survive in its environment through its physical traits and behaviors. Also, the process by which an organism develops this state through natural processes.
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definitions
Progressive In evolution, the now-discounted idea
that all change is toward increasing complexity.
Inheritance of acquired characteristics The incorrect idea that adaptive traits
acquired during an organism’s lifetime can be passed on to its offspring.
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definitions
Fitness The relative adaptiveness of an
individual organism, measured ultimately by reproductive success.
Natural Selection Evolutionary change based on the
differential reproductive success of individuals within a species.