Chapter Two: The Evolution of Evolution

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?

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.

definitions Evolution Fossils Strata Stratigraphy 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.

J. Best Publishing Company Fig 2.2 J. Best Publishing Company

definitions Catastrophists Comparative Anatomy Uniformitarianism 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.

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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Adaptation definitions 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.

Inheritance of acquired characteristics 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.

Fitness Natural Selection definitions 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.

The Evolution of Evolution Summary As the scientific method was applied to the study of the earth, scientists gradually learned to give up their presuppositions.

Questions for further thought The scientific research and ideas of many early biologists and geologists were influenced by philosophical concepts. Do you think such influences ended with people lie Darwin? Can you think of a modern scientific matter that may be influenced by beliefs?

Questions for further thought Whereas biological evolution is not Lamarckian, the evolution of culture is. How so?

Questions for further thought There are those who say that certain areas of scientific research should be avoided either because their results might be misused or because the facts generated might be unpleasant. What sorts of research do you think these people might be referring to? How would you respond to such cautions?