CHAPTER ONE test hypotheses Concept 1 3 In studying nature scientists make observations and then form and o The word science is derived from Latin and means to know o Inquiry is the search for information and explanation o The scientific process includes making observations forming logical hypotheses and testing them The Role of Hypotheses in Inquiry o A hypothesis is a tentative answer to a well framed question o A scientific hypothesis leads to predictions that can be tested by observation or experimentation o Failure to falsify a hypothesis does not prove that hypothesis The Flexibility of the Scientific Method o The scientific method is an idealized process of inquiry o Hypothesis based science is based on the textbook scientific method but rarely follows all the ordered steps Inductive Reasoning o Inductive reasoning draws conclusions through the logical process of induction o Repeating specific observations can lead to important generalizations For example the sun always rises in the east Deductive Reasoning and Hypothesis Testing o Deductive reasoning uses general premises to make specific predictions o For example if organisms are made of cells premise 1 and humans are organisms premise 2 then humans are composed of cells deductive Experimental Controls and Repeatability o A controlled experiment compares an experimental group with a control prediction group o Ideally only the variable of interest differs between the control and o A controlled experiment means that control groups are used to cancel the experimental groups effects of unwanted variables o A controlled experiment does not mean that all unwanted variables are kept constant Types of Data categories o Data are recorded observations or items of information these fall into two Qualitative data or descriptions rather than measurements For example Jane Goodall s observations of chimpanzee behavior Quantitative data or recorded measurements which are sometimes organized into tables and graphs Questions That Can and Cannot Be Addressed by Science o A hypothesis must be testable and falsifiable For example a hypothesis that ghosts fooled with the flashlight cannot be tested o Supernatural and religious explanations are outside the bounds of science Theories in Science o In the context of science a theory is Broader in scope than a hypothesis General and can lead to new testable hypotheses Supported by a large body of evidence in comparison to a hypothesis Overview Inquiring About the World of Life Evolution is the process of change that has transformed life on Earth Biology is the scientific study of life Biologists ask questions such as How a single cell develops into an organism How the human mind works How living things interact in communities Unifying Themes of Biology 1 New properties emerge at each level in the biological hierarchy 2 Organisms interact with other organisms and their physical environment 3 Life requires energy transfer and transformation 4 Structure and function are correlated at all levels of biological organization 5 Cells are an organism s basic units of structure and function 6 Continuity of life is based on heritable information in the form of DNA 7 Feedback mechanisms regulate biological systems 8 Evolution accounts for the unity and diversity of life and the match of organisms Theme New Properties Emerge at Each Level in the Biological Hierarchy to their environment Life can be studied at different levels from molecules to the entire living planet The study of life can be divided into different levels of biological organization Theme Organisms Interact with Other Organisms and the Physical Environment Every organism interacts with its environment including nonliving factors Both organisms and their environments are affected by the interactions and other organisms between them For example a tree takes up water and minerals from the soil and carbon dioxide from the air the tree releases oxygen to the air and roots help form soil Theme Life Requires Energy Transfer and Transformation o A fundamental characteristic of living organisms is their use of energy to o Work including moving growing and reproducing requires a source of carry out life s activities energy o Living organisms transform energy from one form to another For example light energy is converted to chemical energy then o Energy flows through an ecosystem usually entering as light and exiting kinetic energy as heat Theme Structure and Function Are Correlated at All Levels of Biological Organization o Structure and function of living organisms are closely related For example a leaf is thin and flat maximizing the capture of light by chloroplasts For example the structure of a bird s wing is adapted to flight Theme The Cell Is an Organism s Basic Unit of Structure and Function o The cell is the lowest level of organization that can perform all activities required for life o All cells Are enclosed by a membrane Use DNA as their genetic information A eukaryotic cell has membrane enclosed organelles the largest of which is usually the nucleus By comparison a prokaryotic cell is simpler and usually smaller and does not contain a nucleus or other membrane enclosed organelles Theme The Continuity of Life Is Based on Heritable Information in the Form of DNA Chromosomes contain most of a cell s genetic material in the form of DNA deoxyribonucleic acid DNA is the substance of genes to offspring Genes are the units of inheritance that transmit information from parents The ability of cells to divide is the basis of all reproduction growth and repair of multicellular organisms DNA Structure and Function Each chromosome has one long DNA molecule with hundreds or thousands of genes Genes encode information for building proteins DNA is inherited by offspring from their parents DNA controls the development and maintenance of organisms Theme Feedback Mechanisms Regulate Biological Systems Feedback mechanisms allow biological processes to self regulate Negative feedback means that as more of a product accumulates the process that creates it slows and less of the product is produced Positive feedback means that as more of a product accumulates the process that creates it speeds up and more of the product is produced Evolution the Overarching Theme of Biology Evolution makes sense of everything we know about biology Organisms are modified descendants of common ancestors Evolution explains patterns of unity and diversity in living organisms Similar
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