2.4 History and Philosophy of Biology

Why This Section Matters

A significant slice of the Nature of Science subarea asks you to identify a scientist's principal contribution or to recognize a paradigm shift in biology. ETS uses these items to assess whether you understand that scientific knowledge is constructed over time, revised when new evidence arrives, and held together by overlapping lines of support.

Key Historical Figures

Taxonomy and Classification

• Carolus Linnaeus (1707-1778) developed binomial nomenclature (Genus species) and the hierarchical classification of kingdoms, classes, orders, genera, and species. Modern taxonomy retains his framework while adding domain (Woese, 1990) and phylogenetic methods.

Microbiology and Germ Theory

• Anton van Leeuwenhoek (1632-1723) built single-lens microscopes and was the first to describe "animalcules" — protists, bacteria, and sperm cells.
• Louis Pasteur (1822-1895) used swan-neck flask experiments (1859-1862) to demonstrate that broth remained sterile when airborne particles could not enter, definitively disproving spontaneous generation. He also developed pasteurization, vaccines against rabies and anthrax, and the germ theory of disease.
• Robert Koch (1843-1910) formulated Koch's postulates for proving a specific microbe causes a specific disease and identified Mycobacterium tuberculosis and Vibrio cholerae.

Cell Theory

Three contributors are typically cited:

• Matthias Schleiden (1838) - all plants are made of cells.
• Theodor Schwann (1839) - all animals are made of cells; cells are the fundamental unit of life.
• Rudolf Virchow (1855) - Omnis cellula e cellula (every cell comes from a pre-existing cell), closing the circle.

Genetics

• Gregor Mendel (1822-1884) published his pea-plant experiments in 1866. The work was ignored for 34 years and then independently rediscovered around 1900 by Hugo de Vries, Carl Correns, and Erich von Tschermak.
• Thomas Hunt Morgan (1866-1945) demonstrated chromosomal inheritance using Drosophila melanogaster, including sex linkage.
• Barbara McClintock (1902-1992) discovered transposable elements ("jumping genes") in maize; Nobel Prize 1983.

Evolution

• Jean-Baptiste Lamarck (1744-1829) proposed inheritance of acquired characteristics — an early but ultimately incorrect theory of evolutionary change.
• Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913) independently proposed natural selection. Darwin published On the Origin of Species in 1859 after his Beagle voyage observations of the Galapagos finches and other taxa.
• The Modern Synthesis (1930s-1940s) united Darwinian natural selection with Mendelian genetics through the work of Ronald Fisher, J.B.S. Haldane, Sewall Wright, Theodosius Dobzhansky, Ernst Mayr, and George Gaylord Simpson.

DNA Structure

• Friedrich Miescher (1869) isolated "nuclein" (DNA) from white blood cells.
• Frederick Griffith (1928) demonstrated bacterial transformation, suggesting a hereditary substance.
• Avery, MacLeod, and McCarty (1944) identified DNA — not protein — as that hereditary substance.
• Hershey and Chase (1952) used radioactive labeling of phages to confirm DNA as genetic material.
• Rosalind Franklin and Maurice Wilkins produced X-ray diffraction images of DNA, including Photo 51 (1952).
• James Watson and Francis Crick published the double-helix model in Nature on April 25, 1953, drawing on Franklin's data. Watson, Crick, and Wilkins received the 1962 Nobel Prize; Franklin had died in 1958 and was therefore ineligible.

Major Paradigm Shifts

A paradigm shift (Thomas Kuhn, 1962) is a fundamental change in the framework of a scientific field. Biology has experienced several:

Nature of Scientific Knowledge

ETS expects you to articulate the following features in your own teaching:

1. Empirical - rooted in observation and measurement of the natural world.
2. Tentative but durable - subject to revision when new evidence demands it, yet well-established theories (cell theory, evolution, plate tectonics) are not overturned casually.
3. Theory-laden - observations are interpreted through current theoretical frameworks; "raw data" is never fully raw.
4. Socially and culturally embedded - scientists work within communities, and their cultural context can shape which questions they choose to ask, though peer review and replication constrain how those questions are answered.
5. Distinct from technology - science seeks explanation; technology applies that knowledge to solve problems. They feed each other but are not the same.
6. Limited in scope - science cannot answer questions of value, ethics, or supernatural claims. Those questions are real and important but lie outside the methodological reach of science.

These commitments are codified in the Next Generation Science Standards (NGSS) Appendix H, Understanding the Scientific Enterprise: The Nature of Science in the Next Generation Science Standards.