Mader/Inquiry into Life, 9/e

Lecture Enrichment Ideas - Chapter 1

Characteristics of Life
- a. Describe how the molecules in clay soil can dissolve and re-form a matrix pattern that replicates the order of the clay molecules next to them. Technically, this is a "self-replicating molecular assemblage"--one definition of life. Yet everyone knows clay is not living. What is lacking...why aren't the hills "alive"?
- b. Describe the many properties of quartz crystals: that crystals "grow" over time, little crystals are "reproduced" at angles off the sides of parent crystals, the crystal possesses a predictable angular "structure" that is not like the chaotic environment, and sheets of quartz evenshow a response to environmental stimuli--they convert light to current in a piezioelectric effect! With so many features of life, why isn't quartz considered living?
Ecosystems
- a. Outline the levels of organization on the board, from biosphere down to molecular levels. Read off the titles of research articles by your department's faculty and have students locate the closest level of description (i.e., "Metabolic pathways..." would be molecular or cellular, "Life cycle of..." would be population or organismal biology, etc.).
- b. Read job descriptions for biology positions from Science or the Chronicle of Higher Education and challenge students to determine the level of study.
Classification of Living Things
- a. Display an assortment of screws, bolts, nails, brads, staples and other fasteners on the overhead. Ask students to "classify" them in groups for easier display in a store, etc. On what basis do they group screws and bolts, tacks and nails, etc., together (common structures, threading, production methods, functions, etc.)? The basis for biological classification is common phylogenetic origin but likewise uses common structures and functions.
- b. When we discover an antibiotic among the microorganisms, why do we not search randomly among the thousands of others but look closely at its nearest relatives? Why do we test the effectiveness of antibiotics first on mice, and then on primates before testing them on humans? How can classification be predictive of things we do not yet know?
The Process of Science
- a. Buy a recent tabloid newspaper from the newstands featuring a pseudoscience topic; students readily recognize these from the grocery check-out stand. Read one brief account of a particularly preposterous assertion and ask what is necessary for a scientist to believe this, what internal contradictions belie its claims, what tests would be necessary to provide it with scientific legitimacy, etc.
- b. The journals The Skeptic and Skeptical Inquirer provide careful analysis of the actual facts surrounding accounts of spontaneous human combustion, crop circles, diseases that give the appearance of being possessed, etc. Relating these clear cases helps contrast the scientific view with some common uncritical public views.
- c. Briefly explain a case of science fraud, such as Cyril Burt and the twin-IQ studies, Piltdown Man, Lysenkoism, or various recent cases of fraud. Ask students what mechanisms exist to expose fraudulent results.