What Science Is and Is Not What is the goal of science?

What Science Is and Is Not The goal of science is to: investigate and understand the natural world explain events in the natural world use those explanations to make useful predictions

What Science Is and Is Not Science is an organized way of using evidence to learn about the natural world. The word science also refers to the body of knowledge that scientists have gathered.

Scientific Method Observation Hypothesis Experiment Data Analysis/Conclusions Theory

Scientific Method 1. Observation Scientific thinking begins with observation (the process of gathering information about events or processes in a careful, orderly way).

1. Observation continued… Scientific Method 1. Observation continued… The information gathered from observations is called data. Quantitative data are expressed as numbers, obtained by counting or measuring. Qualitative data are descriptive and involve characteristics that can’t easily be measured.

1.Observation continued… Scientific Method 1.Observation continued… Scientists use data to make inferences. An inference is a logical interpretation based on prior knowledge or experience. Happy Sad Sick Mad

Scientific Method 2. Hypothesis A hypothesis is a proposed scientific explanation for a set of observations. “Educated guess” as to why. A hypothesis may be ruled out or confirmed by performing controlled experiments or by gathering new data

More later about designing experiments…… Scientific Method 3. Experiment Experiments must have only 1 variable that is changed to have valuable results. Manipulated/Independent Variable Responding/Dependent Variable More later about designing experiments……

Scientific Method 4. Data Scientists record data, findings, information (quantitative and/or qualitative) from their experiments. They analyze this data to make conclusions.

Scientific Method 5. Analysis/Conclusion Researchers often work in teams to analyze, review, and critique each other’s data and hypotheses. A review process helps ensure conclusions are valid. To be valid, a conclusion must be based on logical interpretation of reliable data.

Scientific Method 6. Theory Hypotheses that have been tested and retested by several scientists can be agreed upon as a theory, rather than an idea/hypothesis. This takes a lot of evidence and usually a lot of time in order for the majority to agree. Theories are not facts, however because they can change if further evidence proves them incorrect.

Science as a Way of Knowing Science is an ongoing process that involves: asking questions observing making inferences testing hypotheses

Science as a Way of Knowing Scientific understanding is always changing. Good scientists are skeptics who question both existing ideas and new hypotheses.

Science and Human Values Decisions involve many factors besides scientific information, including: the society in which we live economic considerations laws moral principles Citizens decide what to do when they vote.

1-2 How Scientists Work

Designing an Experiment a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be controlled. The process of testing a hypothesis includes: Asking a question Forming a hypothesis Setting up a controlled experiment Recording and analyzing results Drawing a conclusion

Designing an Experiment manipulated variable – (independent) variable that is deliberately changed responding variable – (dependent) variable that is observed after/because of the change

Redi’s Experiment In a controlled experiment, only one variable is tested at a time. Redi designed an experiment to determine what caused the sudden appearance of maggots. In his experiment, the manipulated variable was the presence or absence of the gauze covering. The results of this experiment helped disprove the hypothesis of spontaneous generation.

Repeating Investigations Scientists repeat experiments to be sure that the results match those already obtained. Needham's Test of Redi's Findings Needham challenged Redi’s results by claiming that spontaneous generation could occur under the right conditions.

Repeating Investigations Needham’s Test of Redi’s Findings Needham sealed a bottle of gravy and heated it. After several days, the gravy was swarming with microorganisms. Needham concluded that these organisms came from the gravy by spontaneous generation.

Spallanzani's Test of Redi's Findings Spallanzani did not believe that Needham had heated his samples enough! Spallanzani’s experiment showed that microorganisms will not grow in boiled gravy that has been sealed but will grow in boiled gravy that is left open to the air. Interpreting Graphics What variable was controlled in this experiment?

Repeating Investigations Pasteur's Test of Spontaneous Generation Louis Pasteur conclusively disproved the hypothesis of spontaneous generation.

When Experiments Are Not Possible It is not always possible to do an experiment to test a hypothesis. For example: Wild animals must be observed without disturbing them. Ethical considerations prevent some experiments.

How a Theory Develops How a Theory Develops As evidence from numerous investigations builds up, a hypothesis may become so well supported that scientists consider it a theory. In science, the word theory applies to a well-tested explanation that unifies a broad range of observations. No theory is considered absolute truth. As new evidence is uncovered, a theory may be revised or replaced by a more useful explanation.

Copyright Pearson Prentice Hall 1-3 Studying Life Photo Credit: © Andrew Syred/Science Photo Library/Photo Researchers, Inc. Copyright Pearson Prentice Hall

Characteristics of Living Things What are some characteristics of living things? Copyright Pearson Prentice Hall

Characteristics of Living Things No single characteristic is enough to describe a living thing. Some nonliving things share one or more traits with living things. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things share the following characteristics: made up of units called cells reproduce based on a universal genetic code grow and develop obtain and use materials and energy respond to their environment maintain a stable internal environment change over time Copyright Pearson Prentice Hall

Characteristics of Living Things Living things are made up of cells. A cell is the smallest unit of an organism that can be considered alive. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things reproduce. In sexual reproduction, cells from two different parents unite to form the first cell of the new organism. In asexual reproduction, a single parent produces offspring that are identical to itself. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things grow and develop. During an organism’s development, cells differentiate, which means that the cells look different from one another and perform different functions. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things are based on a universal genetic code. Organisms store the information they need to live, grow, and reproduce in a genetic code in a molecule called DNA. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things obtain materials and use energy. The combination of chemical reactions through which an organism builds up or breaks down materials is called metabolism. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things respond to their environment. A stimulus is a signal to which an organism responds. Copyright Pearson Prentice Hall

Characteristics of Living Things Living things maintain a stable internal environment. Although conditions outside an organism may change, conditions inside an organism tend to remain constant. This process is called homeostasis. Copyright Pearson Prentice Hall

Characteristics of Living Things Taken as a group, livings things change over time. Over many generations, groups of organisms typically evolve. Copyright Pearson Prentice Hall

Interdependence in Nature Big Ideas in Biology Interdependence in Nature All forms of life on Earth are connected together into a biosphere, which literally means “living planet.” The relationship between organisms and their environment depends on both the flow of energy and the cycling of matter. Everything depends on everything to live!!! Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Big Ideas in Biology Matter and Energy Life’s most basic requirements are matter that serves as nutrients to build body structure and energy to fuel the processes of life. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Big Ideas in Biology Cellular Basis of Life Organisms are composed of one or more cells, which are the smallest units that can be considered fully alive. Copyright Pearson Prentice Hall

Information and Heredity Big Ideas in Biology Information and Heredity Life’s processes are directed by information carried in a genetic code that is common, with minor variations, to every organism on Earth. That information, carried in DNA, is copied and passed from parents to offspring. Copyright Pearson Prentice Hall

Unity and Diversity of Life Big Ideas in Biology Unity and Diversity of Life All living things are fundamentally alike at the molecular level, even though life takes an almost unbelievable variety of forms. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Big Ideas in Biology Evolution In biology, evolution, or the change in living things through time, explains inherited similarities as well as the diversity of life. Copyright Pearson Prentice Hall

Structure and Function Big Ideas in Biology Structure and Function Structures evolve in ways that make particular functions possible, allowing organisms to adapt to a wide range of environments. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Big Ideas in Biology Homeostasis An organism’s ability to maintain a relatively stable internal environment in the face of changing external conditions is vital to its survival. Copyright Pearson Prentice Hall

Science, Technology, and Society Big Ideas in Biology Science, Technology, and Society Science seeks to provide useful information, but only a public that truly understands science and how it works can determine how that information should be applied. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Branches of Biology Branches of Biology There a many branches of biology. For example: Zoologists study animals. Botanists study plants. Paleontologists study ancient life. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Branches of Biology How can life be studied at different levels? Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Organization of Life Life is organized into several levels. Atoms (O, C, N, H, etc.) Molecules (H20, DNA, etc.) Cells (Smallest unit of LIFE) Tissues (Collection of cells) Organs (Collection of Tissues) Organ Systems (Organs with a common purpose) Organisms (One body of life in a species that is fully functional) Populations of a single kind of organism (aka Species) Community of different organisms in an area (Different Species) Ecosystem (biotic/living and abiotic/nonliving parts) Biosphere (earth) Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Biosphere The part of Earth that contains all ecosystems Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Ecosystem Community and its nonliving surroundings Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Hawk, snake, bison, prairie dog, grass, stream, rocks, air Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Community Populations that live together in a defined area Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Hawk, snake, bison, prairie dog, grass Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Population Group of organisms of one type that live in the same area Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Bison herd Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Organism Individual living thing Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Bison Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Groups of Cells Tissues, organs, and organ systems Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Nervous tissue Brain Nervous system Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Cells Smallest functional unit of life Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Nerve cell Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall Molecules Groups of atoms; smallest unit of most chemical compounds Living things may be studied on many different levels. The largest and most complex level is the biosphere. The smallest level is the molecules that make up living things. Water DNA Copyright Pearson Prentice Hall

Tools and procedures Metric system - international Microscopes Compound Light Microscope – light and mirrors Electron microscope – electrons and magnets Technique Cell culture – Growing cells from one cell in a dish Cell fractionation – Separating parts of a cell by spinning it Work Safe Follow all teacher instructions

Biology in Everyday Life More than any other area of study, biology touches your life every day. Biology provides information about the food you need and the methods for sustaining the world’s food supplies. Biology describes the conditions of good health and the behaviors and diseases that can harm you. Biology is used to diagnose and treat medical problems. Biology identifies environmental factors that might threaten you. Biology helps you understand what effects the quality of your life. Biology provides decision makers with useful information and analytical skills needed to predict and effect the future of the planet. Copyright Pearson Prentice Hall