Evolutionary Theory and Evidence

Descent with Modification

Overview

  • Focuses on key concepts and observations related to biological diversity, evolution, and natural selection.

  • Important topics in this section include:

    • Historical perspectives on biodiversity

    • The development of the theory of evolution

    • Evidence supporting evolution.

Learning Objectives

  1. Describe how biological diversity was understood before Darwin's theory.

  2. Detail the rules of evolution and the observational basis Darwin used to support his theory.

  3. Identify various lines of evidence that support the theory of evolution.

Biological Diversity Pre-Darwin

Early Views of Biodiversity

  • Aristotle (384-322 BC)

    • Proposed that species possess "fixed properties" and were created by God in their current form (special creation).

    • Believed in a hierarchical organization of life called Scala Naturae, where life progresses from inanimate objects to higher forms, emphasizing a divine plan.

Naturalists and Taxonomy

  • Carolus Linnaeus (1707-1778)

    • Established modern taxonomy in his work, Systema Naturae.

    • Known as the founder of taxonomy, he laid the groundwork for classifying organisms.

Paleontology and Evidence of Change

  • Georges Cuvier (1769-1832)

    • Discovered that fossils (e.g., mammoths, mastodons) did not resemble modern species, implying extinction.

  • Mary Anning (1799-1847)

    • Known for her work discovering marine reptiles, further emphasizing the evidence that life changes over time.

Scientific Revolution and Evolving Ideas

Key Scientific Contributions

  • Scientific Revolution (15th-17th Century)

    • Advances in astronomy (Newton, Copernicus, Galileo) challenged geocentric views.

    • Geologists introduced the principle of uniformitarianism, proposing that past geological processes operated similarly to those today, indicating a very old Earth.

    • Natural History and Anatomy - Research by figures such as Leonardo da Vinci and Vesalius demonstrated similarities between species through anatomy, embryology, and geological formations.

Early Evolutionary Theorists

  • Jean-Baptiste Lamarck (1744-1829)

    • Proposed that organisms originated individually from non-living matter and acknowledged the role of the environment in evolution.

    • Introduced the mechanism of inheritance of acquired characteristics, stating organisms differ based on their needs and environmental adaptations.

Malthus and Population Theory

  • Thomas Malthus (1766-1834)

    • Economist who argued that human population growth rates exceed food supply growth, predicting famine and competition for resources.

    • His work inspired Darwin's concept of the **