BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 1 Introduction: The Scientific Study of Life Modules 1.1 – 1.3

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The lives of gray-headed flying foxes are closely entwined with the lives of the eucalyptus trees that form their habitat –Eucalyptus trees provide food and roosting sites for the flying foxes –Flying foxes aid in eucalyptus pollination and help disperse the resulting seeds Life in the Trees

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Flying foxes are becoming an endangered species, partly because of habitat destruction

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Biology is the scientific study of life Interactions between different kinds of organisms affect the lives of all –Recall the example of flying foxes and eucalyptus trees THE SCOPE OF BIOLOGY

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A structural hierarchy of life, from molecules to ecosystems, defines the scope of biology An ecosystem consists of: –all organisms living in a particular area –all nonliving physical components of the environment that affect the organisms (soil, water) 1.1 Life’s levels of organization define the scope of biology

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings At the top of life’s hierarchy is the ecosystem Ecosystems include: –all the organisms in an area, which make up a community –interbreeding organisms of the same species, a population ECOSYSTEM LEVEL Eucalyptus forest COMMUNITY LEVEL All organisms in eucalyptus forest POPULATION LEVEL Group of flying foxes ORGANISM LEVEL Flying fox ORGAN SYSTEM LEVEL Nervous system ORGAN LEVEL Brain Brain Spinal cord Nerve TISSUE LEVEL Nervous tissue CELLULAR LEVEL Nerve cell MOLECULAR LEVEL Molecule of DNA Figure 1.1

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Organisms are made up of: –organ systems –organs –tissues –cells –molecules ECOSYSTEM LEVEL Eucalyptus forest COMMUNITY LEVEL All organisms in eucalyptus forest POPULATION LEVEL Group of flying foxes ORGANISM LEVEL Flying fox ORGAN SYSTEM LEVEL Nervous system ORGAN LEVEL Brain Brain Spinal cord Nerve TISSUE LEVEL Nervous tissue CELLULAR LEVEL Nerve cell MOLECULAR LEVEL Molecule of DNA Figure 1.1

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In discovery science, scientists describe some aspect of the world and use inductive reasoning to draw general conclusions –Example: scientists have described how newborn flying foxes cling to their mother’s chest for the first weeks of life 1.2 Scientists use two main approaches to learn about nature THE PROCESS OF SCIENCE Figure 1.2

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In hypothesis-driven science, scientists use the “scientific method” –They propose a hypothesis –They make deductions leading to predictions –They then test the hypothesis by seeing if the predictions come true

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The main steps of the scientific method 1.3 With the scientific method, we pose and test hypotheses Observation Question Hypothesis Prediction Test: Experiment or additional observation Test does not support hypothesis; revise hypothesis or pose new one Test supports hypothesis; make additional predictions and test them Figure 1.3A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Deductive reasoning is used in testing hypotheses –If a hypothesis is correct, and we test it, then we can expect a particular outcome Case study: flashlight failure Figure 1.3B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Experiments designed to test hypotheses must be controlled experiments Control groups must be tested along with experimental groups for the meaning of the results to be clear

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Case study: spider mimicry Pounce rate (% of trials in which spider jumped on fly) Control group (untreated flies) Experimental group (wing markings masked) Figure 1.3C Figure 1.3D

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Another test of the spider mimic hypothesis: wing transplants Number of stalk and attack responses by spiders Wing markings Normal spider mimic Figure 1.3E Wing waving Mimic with mimic wing transplant ControlsExperimentals Mimic with housefly wing transplant Housefly with mimic wing transplant Normal housefly