01-exploring biology text课件.ppt

Chapter 1;Overview: Biology’s Most Exciting Era Biology Is the scientific study of life;The phenomenon we call life Defies a simple, one-sentence definition;We recognize life By what living things do;Some properties of life;Concept 1.1: Biologists explore life from the microscopic to the global scale The study of life Extends from the microscope scale of molecules and cells to the global scale of the entire living planet;A Hierarchy of Biological Organization;From the biosphere to organisms;From cells to molecules;A Closer Look at Ecosystems;Ecosystem Dynamics;Energy Conversion;The exchange of energy between an organism and its surroundings Often involves the transformation of one form of energy to another;Energy flows through an ecosystem Usually entering as sunlight and exiting as heat;A Closer Look at Cells;The Cell’s Heritable Information;The molecular structure of DNA Accounts for it information-rich nature ;Two Main Forms of Cells;Eukaryotic cells Are subdivided by internal membranes into various membrane-enclosed organelles;Prokaryotic cells Lack the kinds of membrane-enclosed organelles found in eukaryotic cells;Concept 1.2: Biological systems are much more than the sum of their parts A system Is a combination of components that form a more complex organization;The Emergent Properties of Systems;The Power and Limitations of Reductionism;The study of DNA structure, an example of reductionism Has led to further study of heredity, such as the Human Genome Project;Systems Biology;CELL;Systems biology Is now taking hold in the study of life at the cellular and molecular levels Includes three key research developments: high-throughput technology, bioinformatics, and interdisciplinary research teams;Feedback Regulation in Biological Systems;In feedback regulation The output, or product, of a process regulates that very process;In negative feedback An accumulation of an end product slows the process that produces that product;In positive feedback The end product spe