Biology: The Science of Life

Overview

Course No. 1500

Get the complete background and professional guidance to explore in depth the fundamental principles of how living things work, taught by an award-winning professor at Duke University who has specially adapted his acclaimed introductory biology course. One of the greatest scientific feats of our era is the astonishing progress made in understanding biology—the intricate machinery of life—a progress to which the period we are living in right now has contributed the most.

As you read these words, researchers are delving ever deeper into the workings of living systems, turning their discoveries into new medical treatments, improved methods of growing food, and innovative products that are already changing the world. The 72 lectures in this comprehensive exploration of living systems at all levels—from biological molecules to global ecosystems—will give you all the information you need to grasp this fascinating field and its impact on both our own lives and our understanding of the life that surrounds us.

Professor Nowicki presents his subject in a conceptual format, emphasizing the importance of broad principles. Though facts and details are offered in abundance, it is always in the context of developing a framework listeners can readily absorb. Your newfound mastery of the fundamentals of biology will serve you in many ways—whether you want to read the headlines with greater insight, update a subject you studied long ago, view the natural world with new appreciation, become a better-informed voter and consumer, or gain the intellectual stimulation of understanding the basic principles that unite all living things.

Course Structure

1. The Scope of “Life”

The first lecture gives an overview of biology, raising key questions about the nature of life and the origin of living things, and concludes with an outline of the structure of the course.

Duration: 31 min

2. More on the Origin of Life

This lecture outlines the challenges of evolution for living entities such as we recognize today and reviews experimental data suggesting how these challenges might have been met. The process of reproduction identifies the concept of information in biology and introduces the connecting theme for the first third of the course.

Duration: 30 min

3. The Organism and the Cell

Professor Nowicki outlines the hierarchical nature of biological systems and introduces two fundamental levels of the hierarchy: the organism and the cell.

Duration: 30 min

4. Proteins—How Things Get Done in the Cell

This lecture describes the four major classes of biomolecules—lipids, carbohydrates, nucleic acids, and proteins—and discusses the role of proteins in the life of the cell.

Duration: 30 min

5. Which Molecule Holds the Code?

Key experiments in the first half of the 20th century led to the conclusion that DNA is the information-carrying molecule.

Duration: 31 min

6. The Double Helix

Experiments by Rosalind Franklin, Maurice Wilkins, and others led to the discovery by James Watson and Francis Crick of the double helix structure of DNA, suggesting a mechanism by which the information in DNA can be replicated.

Duration: 30 min

7. The Nuts and Bolts of Replicating DNA

After describing how the theory of DNA replication was confirmed, Professor Nowicki summarizes the process, which has been the key to understanding and manipulating biological systems.

Duration: 31 min

8. The Central Dogma

We are introduced to the “central dogma” of molecular biology: Genetic information flows in one direction only—from DNA to RNA to proteins, not in reverse.

Duration: 31 min

9. The Genetic Code

How is protein structure coded in DNA? This lecture describes the experiments that cracked the code and examines the code’s defining properties.

Duration: 30 min

10. From DNA to RNA

Step one in the journey of genetic information from DNA to proteins is the process of transcription, by which messenger RNA is made from a DNA template.

Duration: 29 min

11. From RNA to Protein

Completing the description of how genetic information finds its way to functional proteins, this lecture covers the process of translation, which is the synthesis of proteins based on an RNA template.

Duration: 30 min

12. When Mistakes Happen

We learn the causes for errors that creep into DNA during copying and the mechanisms that have evolved to detect and repair those errors.

Duration: 30 min

13. Dividing DNA Between Dividing Cells

Moving from the molecular level to the level of cells and organisms, this lecture addresses the question: When a new being is produced, how does it acquire DNA from its parents?

Duration: 30 min

14. Mendel and His Pea Plants

The first of two lectures on Gregor Mendel’s 19th-century experiments on the genetics of pea plants shows how this work anticipated the modern understanding of genes, chromosomes, and the formation of gametes during meiosis.

Duration: 30 min

15. How Sex Leads to Variation

This lecture continues the discussion of Mendel’s contributions to genetics, turning to subsequent experiments in which he looked at the transmission of more than one trait.

Duration: 29 min

16. Genes and Chromosomes

We explore the understanding of the cellular and molecular basis of genetics that emerged after Mendel at the turn of the 20th century.

Duration: 31 min

17. Charles Darwin and “The Origin of Species”

At almost the same time that Mendel was working on his laws of inheritance, Charles Darwin was completing his theory of natural selection, which sought to explain the change of species over time.

Duration: 30 min

18. Natural Selection in Action

This lecture presents several examples that demonstrate natural selection in action, including data from both field studies and laboratory experiments.

Duration: 30 min

19. Reconciling Darwin and Mendel

The apparent conflict between Mendel and Darwin was resolved through the “modern synthesis,” which models gene frequency changes in populations.

Duration: 30 min

20. Mechanisms of Evolutionary Change

Natural selection is not the only cause of evolution. Other factors can produce changes in the gene pool of a population, the most notable being genetic drift.

Duration: 30 min

21. What Are Species and How Do New Ones Arise?

Professor Nowicki discusses problems with the biological species concept, introduces alternate definitions, and describes the process of allopatric speciation.

Duration: 30 min

22. More on the Origin of New Species

Continuing the discussion of how new species arise, this lecture looks at sympatric speciation, which occurs in the absence of physical separation of populations.

Duration: 30 min

23. Reconstructing Evolution

How do biologists organize the enormous diversity of living things? We learn about phylogenetic systematics as an approach for reconstructing evolutionary history.

Duration: 31 min

24. The History of Life, Revisited

This lecture takes a final look at the concept of information and evolution in biology by returning to the question of how an original, primordial life form might have given rise to the complex biodiversity observed today.

Duration: 31 min