Biology

18 Chapter 1 Exploring Life and Science

• reproduce; and experience growth, and in many cases development;

• maintain homeostasis to maintain the conditions of an internal environment;

• respond to stimuli; and • have an evolutionary history and are adapted to a way oflife.

1.2 Humans Are Related to Other Animals The classification ofliving organisms mirrors their evolutionary relationships. Humans are mammals, a type of vertebrate in the animal kingdom ofthe domain Eukarya. Humans differ from other mammals, including apes, by their

• highly developed brains; • completely upright stance; • creative language; and • ability to use a wide variety of tools.

Humans Have a Cultural Heritage Language, tool use, values, and information are passed on from one generation to the next.

Humans Are Members of the Biosphere Humans depend on the biosphere for its many services, such as absorption of pollutants, sources of water and food, prevention of soil erosion, and natural beauty. Human population growth and use of resources threaten the biodiversity of the biosphere and is leading to the extinction of many species.

1.3 Science as a Process

Science is a way of knowing about the natural world. The scientific method consists of

• making an observation; • formulating a hypothesis; • carrying out experiments

and observations to collect data;

• coming to a conclusion; and

• presenting results of the study for peer review.

Over time, widely accepted concepts and ideas that explain patterns in the natural world may become principles of scientific theories.

Scientific Method

How the Cause of Ulcers Was Discovered

Dr. Marshall followed Koch's postulates to show that H. pylori causes ulcers.

How to Do a Controlled Study • In an experiment, the test group is exposed to the

experimental variable, while the control group is not. The control group may be given a placebo to ensure that the participants all behave the same during the experiment.

• All groups are otherwise treated the same, and it is best if the subjects and the technicians do not know what group they are in.

• The results and conclusion are published in a scientific journal. '......../

Scientific Journals Versus Other Sources of Information Primary sources of information are best; if secondhand sources are used, the reader needs to carefully evaluate the source. The Internet is not regulated, although URLs that end in .edu, .gov, and .org most likely provide reliable scientific information.

1.4 Making Sense of a Scientific Study In general, when assessing a scientific study you should beware of anecdotal and correlational data because they need further study to be substantiated. When examining graphs, ensure that they clearly show the relationship between quantities.

Statistical Data The standard error tells us how uncertain a particular value is. The statistical significance tells us how trustworthy the results are. The lower the statistical significance, the less likely the results are due to chance and the more likely they are due to the experimental variable.

1.5 Science and Social Responsibility Scientific information is based on observation and experimentation. Therefore, scientists need not make value judgments for us. The use of modern technology has its risks, and all citizens need to be able to make informed decisions regarding how and when technology should be used.

ASSESS ',;fu~~il

Testing Your Knowledge of the Concepts

1. Name and describe the basic characteristics oflife. (pages 2-6)

2. What is homeostasis, and why is it important? Give some examples that show how systems work together to maintain homeostasis. (page 4)

3. What are the major domains and kingdoms of life? (pages 7-8)

4. How do human activities threaten the biosphere? (page 9)

5. Discuss the importance of a scientific theory, and describe several theories basic to understanding biological principles. (page 10)

6. With reference to the steps of the scientific method, explain how scientists arrive at a theory. (page 10)

7. What are Koch's postulates, and what are they used for? (page 11)

8. What is a control group, and what is the importance of a control group in a controlled study? (page 12)

9. How do science and technology improve our lives? (pages 16-17)

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Chapter 1

A. Computer Homework B. Text Homework

Extra

1-9 Answer questions 1-9 in Testing Your Knowledge- page 18

10. What is a placebo and why might we use one when we investigate the effect of drugs on people? 11. What is the difference between qualitative and quantitative data? Which is more accurate? 12. What is an independent (experimental) variable? Where do we put it on a graph?

13 What is a dependent variable? Where do we put it on a graph? 14. What is a controlled variable? 15. Develop a "pretend" study and write a hypothesis. Graph your pretend results and label and identify the independent and dependent variables. 16.Why is Wikipedia not considered a reputable journal and why should you not cite it in your research

assignments?

Read the Articles: "The Mechanisms of a Controlled Trial" and "New Drugs Stir Debate on Rules of Clinical Trials".

Write a short opinion paper (at least 2 pages). Include a short summary of the story of the two cousins and your feelings about what happened. If you were the doctors involved in studying this drug, would you break the protocols (rules) to give the drug to more patients if it ruined the study (compromised the data). Remember, if the data is unreliable, it will be even more difficult, and take more time to get the drug to market. The study of PLX4032 was an unblinded study; do you think that the events in the study would have been less emotional if it had been a double blind study? If we do not have strictly controlled studies, can we really understand the true effects of a drug? Do we know the long term effects of the drug? If you were the director of the study what would you do?

This paper will be graded as a quiz and is due ______ _

_ 06joumall mader 13 fall 2013

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