Natural Sciences 2294
Darwin and the Foundations of Evolutionary Biology

INSTRUCTOR: Robert J. O’Hara

DESCRIPTION: An introduction to some of the fundamental ideas that underlie the historical study of nature, with a consideration of their humanistic relations. Readings from original as well as secondary sources. Topics include species, natural selection, geologic time, biogeography, and systematics. Suitable for non-science majors.

REQUIRED TEXTS: (1) Charles Darwin, On the Origin of Species (reprint of first edition, 1859); (2) Peter Bowler, Evolution: The History of an Idea (revised edition, 1989); (3) various short papers and extracts to be announced.

RECOMMENDED TEXTS: (1) Linda Gamlin & Gail Vines, eds., The Evolution of Life (1987); (2) Goode’s World Atlas, 18th edition (an atlas of some kind will be needed to complete some of the assignments; students may use an atlas they already have, the Goode’s atlas, or an atlas in the library); (3) some of the texts we will read are old and some specialized, so students are expected to have and make use of a good dictionary.

RESERVES: Copies of the required and recommended texts will be on reserve in the library.

GRADING AND EXAMS: Grades will be based on a species biography project (30%), one exam (60%), and a memorization assignment (10%). The species biography project and memorization assignment are described below; the exam will consist of short essay and identification questions on the material covered in the course.

Outline of Topics

1. Introduction

Natural history and its place in the sciences. The history of nature in the Nineteenth Century and before. Natural theology as a research program. Darwin’s life and times. The idea of evolution. How to study an old text. Readings from Bacon, the Bible, Bowler (Chapter 1), Cowper, Darwin (Autobiography selections, Origin Introduction), Ray, and Whewell.

2. Species: Essentialism and Population Thinking

Animals and plants in nature seem to come in various “kinds” known as species. What are species? Are the “species” of animals and plants different in any way from the “kinds” we recognize among inanimate objects? Readings from Buffon, Darwin (Origin I & II), Emerson, Mayr, and Plato.

3. Natural Selection

Natural selection is the evolutionary mechanism Darwin proposes in the Origin; it is the driving force of evolutionary change. What is distinctive about natural selection as a process, and what is its relation to determinism and randomness? Readings from Bowler (Chapter 6), Darwin (1858 paper, Origin III & IV), Malthus, and Wallace.

4. The Discovery of Time

The acceptance of evolution was facilitated by the earlier work of geologists, who had shown by the early 1800’s that the earth had a long and complicated history. What sorts of evidence and what methods of reasoning did geologists use to reconstruct the history of the earth? Readings from the Bible, Bowler (Chapter 2), Cowper, Darwin (Origin IX), Gould, Lyell, and Tennyson.

5. The Geographical Distribution of Animals and Plants

The species of animals and plants are distributed neither uniformly nor randomly across the surface of the earth. What does the geographical distribution of animals and plants tell us about their history and the history of the earth? Readings from Browne, Darwin (Origin XI & XII), Mayr, and Wallace.

6. The Natural System

The large-scale structure of living diversity—the universal arrangement or classification within which all animals and plants have a place—is known as “the Natural System.” What was the role of systematics, the study of the Natural System, in the development of evolutionary thought? Readings from Bowler (Chapter 3), Darwin (Origin X & XIII), Jenyns, Pope, Stevens, and Wallace.

7. Recapitulation and Conclusion

The historical sciences, the history and classification of the sciences, and evolution of science. Readings from Darwin (Origin XIV), Toulmin, and Wedgwood.

SPECIES BIOGRAPHY PROJECT: Near the beginning of the term students will select or be assigned a species that occurs in the local area. Over the course of the term each student will collect information on this species and assemble it into a short (fewer than ten pages) species “biography” of the type that might appear in a faunal or floral work. This exercise may involve both examination of the species in nature, as well as research on it in the library. The species biography should include: (1) The name of the species and a statement of its position in standard classifications. (2) A description of the characteristics of the species that serve to distinguish it from similar species (i.e., how you know it is x, instead of the similar species y or z). (3) A map of the species’ geographical distribution, and a discussion of any geographical variation that the species exhibits. (4) A list of references from which the above materials were drawn. The completed species biographies are to be handed in at the time of the final exam.

MEMORIZATION ASSIGNMENT: As a part of the final exam you will be asked to reproduce word for word the two quotations below (six sentences in all). These quotations embody two of the ways of seeing the world that we will examine in this course. The first, from the American essayist Ralph Waldo Emerson, presents the “essentialist” view of nature, a view rejected by Charles Darwin’s evolutionary biology. The second, the concluding paragraph of Darwin’s Origin of Species, summarizes the idea of evolution by natural selection as Darwin understood it. It is interesting to note that even though the views of nature that are embodied in these quotations differ sharply, both authors inserted into their statements a measure of consolation for those who find their views disturbing.

In countless upward-striving waves
The moon-drawn tide-wave strives;
In thousand far-transplanted grafts
The parent fruit survives;
So, in the new-born millions,
The perfect Adam lives.
Not less are summer-mornings dear
To every child they wake,
And each with novel life his sphere
Fills for his proper sake.

Ralph Waldo Emerson, 1844, “Nominalist and Realist”

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. (Charles Darwin, 1859, On the Origin of Species.)