1 Biology and You-Chapter 1

2 I. Themes of Biology A. Living Organisms have certain characteristics in common. 1. Biology is the study of life.

3 B. Seven Themes Unify the science of Biology 1. Cellular structure and function= cells. a. All living things are composed of one or more cells. b. Cells are highly organized, tiny structures with thin membranes.

4 2. All living things reproduce. a. Reproduction is the process by which organisms make more of their own kind from one generation to the next.

5 3. Metabolism a. Living organisms perform many different chemical reactions in order to obtain and use energy to run the processes of life. b. Metabolism is the sum of all the chemical reactions carries out in an organism.

6 4. Homeostasis a. All living organism must maintain a stable internal environment in order to function properly. b. The maintenance of stable internal conditions in spite of changes in the external environment is called homeostasis.

7 5. Heredity a. All living things are able to pass on their characteristics to their offspring through genes that are passed from parent to offspring each generation.

8 b. The passing of traits from parent to offspring is called heredity. c. A change in the DNA of a gene is called a mutation.

9 6. Evolution a. Change in the inherited traits of species over time is called evolution. b. A species is a group of genetically similar organisms that can produce fertile offspring. c. Organisms with favorable genes are more likely to survive and reproduce natural selection.

10 7. Interdependence a. A biological community is a group of interacting organisms. b. Ecology is the science that studies the interactions of living organisms with one another and with the nonliving part of their environment.

11 II. Biology in our world A. Living in harmony with our environment 1. In 1999, the world ’ s human population was passed 6 billion people! 2. Humans are seriously harming other creatures that share our planet.

12 B. Feeding a growing population 1. As the population continues to grow, the demand for food is going to strain our ability to feed all the people. 2. Genetic engineers are transplanting beneficial plants genes into other plants to create crops that are more resistant to insects and microorganisms.

13 C. Biology Can Help fight Disease 1. AIDS- Acquired Immune Deficiency Syndrome. 2. Cancer 3. Cystic Fibrosis

14 III. Scientific Process A. Shared observations help to solve scientific puzzles 1. Observation is the act of noting or perceiving objects or events using the senses.

15 B. Collecting observations C. Asking questions 1. Observations of the natural world often raise questions.

16 D. Forming hypotheses and making predictions 1. A hypothesis is an explanation that might be true- a statement that can be tested by additional observations or experimentation. 2. A prediction is the expected outcome of a test, assuming the hypothesis is correct.

17 E. Confirming predictions 1. An experiment (a planned procedure to test a hypothesis) must be performed. 2. A control group is a group in an experiment that receives no experimental treatment.

18 3. The factor that is varied in an experiment is called the independent variable. 4. The variable that is measured in an experiment is called the dependent variable.

19 F. Drawing a conclusion 1. Once data are collected and analyzed, a conclusion is made as to whether the data support the hypothesis. 2. Further analysis is conducted to determine any problems in the experiment.

20 G. Publishing results in scientific journals 1. Once a scientist completes an experiment he/she will write up a report and print it in a science journal.

21 H. Theories are Ideas Supported by a Great deal of Evidence 1. A theory is a set of related hypotheses that have been tested and confirmed many times by many scientists.

22 2. To scientists a theory represents that of which they are most certain. 3. To the public, theory may imply a lack of knowledge, a guess.

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24 The End