What are the basic concepts of Lamarck’s theory of the mechanism of evolution?
Lamarck believed that changes occur in an organism during its lifetime as a consequence of adapting
to a particular environment. Those parts that are used tend to become prominent, while those that are not
tend to degenerate (use-disuse concept). Further, the changes that occur in an organism during its lifetime
are then passed onto its offspring; i.e., the offspring inherit these acquired characteristics. Integral to
Lamarck’s theory was the concept of a deep-seated impulse toward higher levels of complexity within the
organism, as if each creature were endowed with the will to seek a higher station in life.
The chief defect in Lamarck’s theory is the view that acquired characteristics are inherited. With our
present understanding of the control of inheritance by the genetic apparatus, we realize that only changes
in the makeup of genes could lead to permanent alterations in the offspring. However, at the time of
Lamarck’s formulation, little was known of the mechanism of genetics. Even Darwin incorporated some
of the Lamarckian views of the inheritance of acquired characteristics into his own thinking.
Lamarck’s theory of evolution should not be regarded as being merely a conceptual error. Rather, it
should be viewed as a necessary step in a continuing development of greater exactness in the description
of a natural process. Science moves in slow, tentative steps to arrive at greater certainty. The truths of
today’s science are dependent on the intellectual forays of earlier investigators. They provide the shoulders
on which others may stand to reach for more fruitful explanations.
Lamarck believed that changes occur in an organism during its lifetime as a consequence of adapting
to a particular environment. Those parts that are used tend to become prominent, while those that are not
tend to degenerate (use-disuse concept). Further, the changes that occur in an organism during its lifetime
are then passed onto its offspring; i.e., the offspring inherit these acquired characteristics. Integral to
Lamarck’s theory was the concept of a deep-seated impulse toward higher levels of complexity within the
organism, as if each creature were endowed with the will to seek a higher station in life.
The chief defect in Lamarck’s theory is the view that acquired characteristics are inherited. With our
present understanding of the control of inheritance by the genetic apparatus, we realize that only changes
in the makeup of genes could lead to permanent alterations in the offspring. However, at the time of
Lamarck’s formulation, little was known of the mechanism of genetics. Even Darwin incorporated some
of the Lamarckian views of the inheritance of acquired characteristics into his own thinking.
Lamarck’s theory of evolution should not be regarded as being merely a conceptual error. Rather, it
should be viewed as a necessary step in a continuing development of greater exactness in the description
of a natural process. Science moves in slow, tentative steps to arrive at greater certainty. The truths of
today’s science are dependent on the intellectual forays of earlier investigators. They provide the shoulders
on which others may stand to reach for more fruitful explanations.
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