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The Meaning of Life

In Search of an Answer


Author(s)

Lior M. Burko
Science
Theiss Research/Chamblee Charter High School
L.Burko@TheissResearch.org

Abstract

This case study takes the form of a dialogue between three students searching for a definition of life. The characters are very loosely based on Galileo’s Dialogue Concerning the Two Chief World Systems. The three students are a physics student (Dave/Salviati), a biology student (Mary/Sagredo), and a chemistry student (John/Simplicio). The case consists of two parts. The first part examines the need for a definition of life, and the two most common approaches: (1) define life by listing the properties of life as we know it (e.g., organization, metabolism, homeostasis, growth, reproduction, response to stimuli, and evolution), and (2) the Joyce definition that NASA uses, i.e., life is a self-sustained chemical system capable of undergoing Darwinian evolution. The second part of the case study discusses the approach of Schrödinger: life is defined by physical principles, specifically those of entropy and free energy. The case was designed for an introductory course on astrobiology, but it can also be used in any course that discusses thermodynamics (specifically, the second law of thermodynamics) or the definition of life (e.g., biology courses).


Objectives

  • Articulate the advantages and disadvantages of using conventional definitions and approaches for the definition of life.
  • Compare and contrast the Clausius and the Kelvin versions of the second law of thermodynamics, and their relationship to systems outside of equilibrium, specifically living systems.
  • Compare and contrast the definitions of life offered by Joyce (NASA), Schrödinger, and biology textbooks, including their relative advantages and disadvantages.

Keywords

Life; entropy; thermodynamics; extraterrestrial life; astrobiology; Schrödinger;

Topical Areas

N/A

Educational Level

High school, Undergraduate lower division

Format

PDF

Type / Methods

Directed, Discussion

Language

English

Subject Headings

Astronomy  |   Biology (General)  |   Physics  |   Science (General)  |  


Date Posted

11/22/2021

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