The Science of Biology Chapter 1 Pages 2 - 33 Updated July 5, 2004 Created by C. Ippolito July 5, 2004

What is the goal of science? Chapter 1 Section 1 Pages 3 - 7 What is Science What is the goal of science? Chapter 1 Section 1 Pages 3 - 7 Updated July 5, 2004 Created by C. Ippolito July 5, 2004

What Science Is and Is Not examines the natural world; collects and organizes information in an orderly manner; Looks for patterns and connections between events; Proposes explanations that can be tested. Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Science Consists of two major parts: It is an organized process that uses evidence to learn about the natural world; It is the body of knowledge that has been built up using the process. Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Thinking Like a Scientist Scientists begin with: Observation – information gathered using the senses. Data – information gathered by observing. Quantitative – presented as numbers (counted or measured). Qualitative – presented as descriptions, involve characteristics that can’t be counted or measured. Inference – logical interpretation of data based on prior knowledge or experience. Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Explaining and Interpreting Evidence Hypothesis – is a proposed scientific explanation that can be tested for a set of observations. Hypotheses are tested by: Controlled experiments Gathering more data Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Science as a Way of Knowing Science always changes: New tools, techniques, discoveries Existing ideas questioned and retested New hypotheses formed Scientific view: Universe is a collection of parts and processes that interact Interaction governed by basic natural laws Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Science and Human Values Goals of science: to understand the natural world; to explain natural world; Use explanations to predict and improve quality of life Bioethics: Considers how discoveries affect Moral principles Social laws Updated July 5, 2004 Created by C. Ippolito July 5, 2004

How Scientists Work How do scientists test hypotheses? How does a scientific theory develop? Chapter 1 Section 2 Pages 8 - 15 Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Scientific Method Aristotle’s Method Modern Method Ask Question Make Observations Form Hypothesis Explain with Reason Form Conclusion Modern Method Ask Question Make Observations Form Hypothesis Test by Experiment Record and Analyze Results Form Conclusion Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Setting Up a Controlled Experiment Variables – factors that can change results (equipment used, type of material, amount of material, temperature, light, and time) Manipulated (Independent) Variable – changed to see its effect Responding (Dependent) Variable – observation changes in response to the manipulated variable Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Controlled Experiment Process used to test a hypothesis. Only one variable is changed at a time. All other variables are unchanged or controlled. Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Where Do Living Things Originate Spontaneous Generation (Abiogenesis) Life can come from non living material Mice from grain Bees from dead bull Maggots from meat Scientists: Aristotle Needham Biogenesis Life can only come from preexisting life Scientists: Redi Spallanzani Pasteur Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Redi Experiment (Biogenesis) Francesco Redi – 1668 Italy Problem: How do maggots appear on meat? Hypothesis: If flies cannot reach meat, then maggots will not form. Manipulated (Independent) Variable – covered jars Responding (Dependent) Variable – maggots do not appear on meat Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Anton Leeuwenhoek’s Discovery Dutch lens maker invented simple microscope Found “animalicules” in rain water spontaneous generation? Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Needham Experiment (abiogenesis) John Needham – mid 1700 England Problem: Can animalicules arise from gravy? Hypothesis: If heat kills all existing life in the gravy then animalcules can form from gravy. Manipulated (Independent) Variable – heated and sealed flasks Responding (Dependent) Variable – animalicules appear in flasks Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Spallanzani’s Experiment (biogenesis) Lazzaro Spallanzani – mid 1700 Italy Problem: Microorganisms can only arise from other microorganisms in the gravy? Hypothesis: If heat kills all existing life in the gravy then sealed flasks will not have microorganisms. Manipulated (Independent) Variable – heated and sealed flasks Responding (Dependent) Variable – microorganism did not appear in flasks Vital Force of Air not allowed in!!! Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Pasteur’s Experiment (biogenesis) Louis Pasteur – 1864 France Problem: Microorganisms can only arise from other microorganisms carried by the air into flasks? Hypothesis: If heat kills all existing life in the gravy and only air is allowed in then flasks will not have microorganisms. Manipulated (Independent) Variable – heated swan necked flasks Responding (Dependent) Variable – microorganisms did not appear in flasks Updated July 5, 2004 Created by C. Ippolito July 5, 2004

How a Theory Develops Theory well tested explanation repeatedly verified by many scientists applies to broad range of observations Updated July 5, 2004 Created by C. Ippolito July 5, 2004