Campbell Biology Chapter 1.3-1.4: Scientific Inquiry PDF

Chapter 1 Biology and Its Themes Lecture Presentations by Nicole Tunbridge and © 2021 Pearson Education Ltd....

Chapter 1 Biology and Its Themes Lecture Presentations by Nicole Tunbridge and © 2021 Pearson Education Ltd. Kathleen Fitzpatrick CONCEPT 1.3: In studying nature, scientists form and test hypotheses The word science is derived from Latin and means “to know” Inquiry is the search for information and explanations of natural phenomena Scientists use a process of inquiry that includes making observations, forming logical hypotheses, and testing them Exploration and Observation Biology begins with careful observation Observations can reveal valuable information about the natural world Biologists also rely heavily on the published contributions of fellow scientists They build on the foundation of existing knowledge Identifying relevant publications is easier than in the past, thanks to indexed and searchable electronic databases Gathering and Analyzing Data Recorded observations are called data Qualitative data often take the form of recorded descriptions Quantitative data are expressed as numerical measurement, organized into tables and graphs Figure 1.21  Inductive reasoning derives generalizations from a large number of specific observations Careful observations and data analyses, along with generalizations reached by induction, are fundamental to our understanding of nature Forming and Testing Hypotheses In science, a hypothesis is an explanation, based on observations and assumptions, that leads to a testable prediction It must lead to predictions that can be tested by making additional observations or by performing experiments An experiment is a scientific test, carried out under controlled conditions  For example: Observation: Desk lamp doesn’t work Question: Why does’t the desk lamp work? Hypothesis 1: The bulb is burnt out Hypothesis 2: The bulb is not screwed in properly Both these hypotheses are testable Figure 1.22 Deductive Reasoning Deductive reasoning uses general premises to make specific predictions Initial observations may give rise to multiple hypotheses We can never prove that a hypothesis is true, but testing it in many ways with different sorts of data can significantly increase our confidence in it Questions That Can and Cannot Be Addressed by Science A hypothesis must be testable For example, a hypothesis that ghosts fooled with the desk lamp cannot be tested Supernatural and religious explanations are outside the bounds of science Animation: Introduction to Experimental Design The Flexibility of the Scientific Process The scientific method is an idealized process of inquiry However, very few scientific inquiries adhere rigidly to this approach Backtracking may be necessary partway through the process In other cases, observations may be too puzzling to prompt well-defined questions, until further studies are complete Figure 1.23 A Case Study in Scientific Inquiry: Investigating Coat Coloration in Mouse Populations Color patterns of animals vary widely in nature, sometimes even between members of the same species Two populations of mice of the same species (Peromyscus polionotus), but with different color patterns reside in different environments The beach mouse lives on white sand dunes with sparse vegetation; the inland mouse lives on darker soil Figure 1.24  The two types of mice match the coloration of their habitats Natural predators of these mice are all visual hunters Francis Bertody Sumner hypothesized that the color patterns had evolved as adaptations to protect the mice from predators In 2010, Hopi Hoekstra and a group of students tested this hypothesis  The researchers predicted that mice that did not match their habitat would be preyed on more heavily than mice that did match the surroundings They built models of mice, painted them to match one of the surroundings, and placed equal numbers of each type of model in each habitat They then recorded signs of predation The data fit the key prediction of the camouflage hypothesis Figure 1.25 Video: The Making of the Fittest: Natural Selection and Adaptation (Rock Pocket Mouse) Variables and Controls in Experiments In a controlled experiment, an experimental group (the non-camouflaged mice in this case) is compared with a control group (the camouflaged mice) Experimental variables are features or quantities that vary in an experiment The independent variable is the one that is manipulated by the researchers The dependent variable is the one predicted to be affected in response Theories in Science In the context of science, a theory is Broader in scope than a hypothesis General enough to lead to many new, testable hypotheses Supported by a large body of evidence in comparison to a hypothesis CONCEPT 1.4: Science benefits from a cooperative approach and diverse viewpoints Most scientists work in teams, which often include graduate and undergraduate students Good communication is important in order to share results through seminars, publications, and websites Research papers are not published until vetted by colleagues in the “peer review” process Building on the Work of Others Scientists check each other’s claims by performing similar experiments If experimental results are not repeatable, the original claim will have to be revised It is not unusual for different scientists to work on the same research question  Scientists cooperate by sharing data about model organisms (for example, the fruit fly Drosophila melanogaster) There are several other popular model organisms as well Biologists approach interesting questions from different angles Science, Technology, and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose Science and technology are interdependent  The combination of science and technology can have dramatic effects on society For example, the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases Debates on technology center more on “should we do it” than “can we do it” Ethical issues that arise from new technology can have as much to do with politics, economics, and cultural values as with science and technology