Introduction to the Scientific Theory

Introduction to the Scientific Theory
Chapter 1: Pg. 3-14

What is Science?

What is Science? The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions. “Knowledge, especially that is gained through experience.”

Intro into Biology So why study Science? Why do we even care?
Has Science really effected YOUR life?

The Steps of the Scientific Method
Step 1: State the Problem Step 2: Form a Hypothesis Step 3: Perform an Experiment Step 4: Record the Data Step 5: Analyze the Data Step 6: Draw a Conclusion

So what is involved??? It starts with a Purpose/Problem
Identifying a problem that needs to be solved or investigated What is your question? What are you trying to determine?

Develop a Hypothesis Hypothesis: is a proposed scientific explanation for a set of observations. Educated guess based on what is already known A prediction of what you think will happen

Now to design an experiment
A Controlled Experiment: is an experiment in which only one variable is changed at a time. All other variables should be kept unchanged or controlled. Group whose conditions remain the SAME and are NOT exposed to experimental variable.

Factors that can change in an experiment is called a Variable Variables used in the experiment: the control and experimental groups are designed to be identical except for one factor or variable

Independent Variable: The factor that is changed in an experiment “What do I change?” Variable that the experimenter MANIPULATES

Dependent Variable: The variable that is measured in an experiment. “What do I observe?” Variable that changes as a result of what the experimenter manipulated. Control Variable: The variable is kept constant to prevent their influence on the effect of the independent variable on the dependent. “What do I keep the same?”

Control Variable: The variable is kept constant to prevent their influence on the effect of the independent variable on the dependent. “What do I keep the same?”

Observations Process of gathering information about events or processes in a careful, orderly way. The information gathered is called Data

Thinking like a scientist
How does science work?- You must THINK like a scientist Observations: process of gathering information about events or process

Thinking like a scientist
Information gathered from observations is called Data Quantitative Data Expressed in numbers, obtained by counting or measuring Qualitative Data Data that is descriptive

Analyzing Data Review your Data Place graph in a table Look for trends
Ask questions… Do you need to collect more data? Did you make any mistakes

Analyzing Data Make a Graph On the graph place:
Independent variables on the x-axis Dependent Variables on the y-axis

Dependent Variable Independent Variable

How to determine the scale of each axis
Determine the scale of each axis, separately. Scale is the value given to each grid of the graph along each axis. Use as much of the graph as possible on each axis. Determine the range of each axis by subtracting the lowest data value (or zero) from the highest data value Highest Lowest Range

Count the number of grids/lines on each axis # of grids c) Divide the range of data values by the number of grids on each axis. Range # of Grids Interval

Let “zero” be the origin for both axis unless the data makes it unrealistic. Maintain the same interval throughout an axis.

Interpreting Data After collecting data:
Find meaning to the collected data and make conclusions of the data Find if certain factors (variables) changed or remained the same

1. Identify the graph that matches each of the following stories:
I had just left home when I realized I had forgotten my books so I went back to pick them up. Things went fine until I had a flat tire. I started out calmly, but sped up when I realized I was going to be late.

How many total miles did the car travel?
What was the average speed of the car for the trip? Describe the motion of the car between hours 5 and 12? What direction is represented by line CD? How many miles were traveled in the first two hours of the trip? Which line represents the fastest speed?

Drawing conclusions… Once data are collected and analyzed, a conclusion is made as to whether the data supports the hypothesis. A hypothesis can be supported but never proven because another experiment with new data and new information may alter the conclusion.

Designing an Experiment
Scientific Method Designing an Experiment State the Problem Form a Hypothesis Set Up a Controlled Experiment Record Results Analyze Results Draw a Conclusion Publish Results

Problem #1 Dr. Smith thinks the drug, AZT, will cure AIDS. He takes 100 patients with AIDS and gives the drug AZT to 50 of them (Group A). To the other 50, he gives them a drug that looks just like AZT, but is really just sugar (Group B). In one year, 30 patients in group A are still healthy, 10 patients in group B are still healthy. In two years, 25 patients in group A are still healthy. 8 patients in group B are still healthy.

Hypothesis What was the hypothesis? (What did Dr. Smith think would happen?) The drug AZT will cure AIDS.

Make a Chart Make a chart showing the # of people who are still healthy in group A versus the # of people who are still healthy in group B over the entire length of the experiment.

Data Chart # Still Healthy Group A # Still Healthy Group B At start
After 1 year After 2 years 50 50 30 10 25 8

Control Group Which group was the control group? How do you know?
Group B because they did NOT receive the drug, the experimental variable. Their conditions remained the same.

Experimental Group Which group was the experimental group? How do you know? Group A, because they had their conditions manipulated by taking the drug AZT.

Independent Variable What was the independent variable? In other words, what did Dr. Smith make different between group A and group B? The drug given (AZT or no drug/placebo)

Dependent Variable What was the dependent variable? In other words, what changed at the end of the experiment as a result of the independent variable? The number of healthy people, because it depended on the type of drug given which was the independent variable.

The number of healthy people
Checking your Answer If your response for questions 4 & 5 are correct, the sentence below should make sense when you fill in the blanks. ____________________________ (Dependent Variable, #5 answer) depends on ____________________________. (Independent Variable, #4 answer) The number of healthy people The drug given

Conclusion What should Dr. Smith's conclusion be?
The drug AZT will help to prevent AIDS.

What is the Scientific Theory?
A theory is an explanation or model based on observation, experimentation and reasoning, especially one that has been tested and confirmed as a general principle helping to explain and predict natural phenomena

Theory A theory unites and explains a broad range of observations.
No absolute certainty in a scientific theory. The possibility always remains that future evidence will cause a scientific theory to be revised or rejected.

Theories…. THEORY OF EVOLUTION BIG BANG THEORY GLOBAL WARMING
Many many more……

Bell Ringer 1/24/12 What is the difference between Quantitative and Qualitative Data? How do you formulate, design and conduct scientific experiments?

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

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

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

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

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

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

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

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

Living things respond to their environment. A stimulus is a signal to which an organism responds. 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

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

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

Big Ideas in Biology Science as a Way of Knowing
Science is not just a list of “facts.” The job of science is to use observations, questions, and experiments to explain the natural world. 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 organsims and their enviroment depends on both the flow of energy and the cycling of matter. 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

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

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

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

Branches of Biology There a many branches of biology. For example:
Zoologists study animals. Botanists study plants. Paleontologists study ancient life. Taxonomy: Discipline of classifying organisms and assigning each organism a universally accepted name. Copyright Pearson Prentice Hall

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

Some of the levels at which life can be studied include: molecules
Branches of Biology Some of the levels at which life can be studied include: molecules cells organisms populations of a single kind of organism communities of different organisms in an area the biosphere Copyright Pearson Prentice Hall

Branches of Biology 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

Community and its nonliving surroundings
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

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

Branches of Biology 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

Branches of Biology Organism Individual living thing Bison
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

Branches of Biology 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

Branches of Biology Cells Smallest functional unit of life=Cells*****
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

Branches of Biology 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

Branches of Biology At all these levels, smaller living systems are found within larger systems. Copyright Pearson Prentice Hall

Biology in Everyday Life
More than any other area of study, biology touches your life every day. Copyright Pearson Prentice Hall

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. Copyright Pearson Prentice Hall

Biology is used to diagnose and treat medical problems. Biology identifies environmental factors that might threaten you. Copyright Pearson Prentice Hall

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

1-3 Copyright Pearson Prentice Hall

An increase in size is known as growth. metabolism. development.
1-3 An increase in size is known as growth. metabolism. development. differentiation. Copyright Pearson Prentice Hall

Which of the following is NOT a characteristic of all living things?
1-3 Which of the following is NOT a characteristic of all living things? use of energy made of cells stable internal environment need for oxygen Copyright Pearson Prentice Hall

Which of the following are branches in the study of biology?
1-3 Which of the following are branches in the study of biology? cells, tissues, organs, and organisms botany, cell biology, ecology, and zoology populations, communities, and ecosystems the genetic code, evolution, and the biosphere Copyright Pearson Prentice Hall

The genetic code is carried in Water. DNA. proteins. soil.
1-3 The genetic code is carried in Water. DNA. proteins. soil. Copyright Pearson Prentice Hall

organisms, cells, populations, molecules, ecosystems
1-3 Which of the following shows the levels of organization in correct order from the simplest to the most complex? organisms, cells, populations, molecules, ecosystems ecosystems, populations, organisms, cells, molecules molecules, cells, organisms, populations, ecosystems molecules, organisms, cells, populations, ecosystems Copyright Pearson Prentice Hall

END OF SECTION

Introduction to the Scientific Theory

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