Chapter 1 Biology Dr. Steve W. Altstiel Biology and You Chapter 1 Biology Dr. Steve W. Altstiel

Themes of Biology Characteristics of Living Organisms How do we know if something is alive? What does being alive mean? Biology - the study of life.

Unifying Themes of Biology Cellular Structure and Function All living things are made up of one or more cells. Cells – highly organized, tiny membrane-bound structures. Smallest unit capable of all life functions. Reproduction All living things can reproduce. Reproduction – the process by which organisms make more of their kind from one generation to the next. Metabolism Metabolism – the sum of all of the chemical reactions carried out in an organism. Chemical reactions are carried out to obtain and use energy. All living things use energy to grow, to move, and to process information.

Unifying Themes of Biology Homeostasis All organisms must maintain a stable internal environment in order to function properly. Homeostasis – the maintenance of stable internal conditions in spite of changes in the external environment. Heredity Organisms pass on traits to their offspring through genes from parents to offspring. Heredity – passing of traits from parents to offspring. Gene – the basic unit of heredity. Coded in a DNA (Deoxyribonucleic acid) molecule. Mutation – damage or a change in a gene in DNA.

Unifying Themes of Biology Evolution Changes in the inherited characteristics of species over generations. Species – a group of genetically similar organisms that can produce fertile offspring. Natural Selection – the process in which organisms with favorable traits are more likely to survive and reproduce.

Unifying Themes of Biology Interdependence Organisms in a biological community live and interact with other organisms. Community – a group of interacting organisms. Ecology – the branch of Biology that studies the interactions of organisms with one another and with the nonliving part of their environment.

Bell Ringer Imagine that all the birds around the school are dying. How might you investigate the problem? In your notebook, write a brief description of your investigation. Which stages of the scientific method are represented in your answer?

Scientific Processes Scientific Method

Stages of Scientific Investigations How can we determine if something is a fact or an opinion? How can we determine an answer to a problem? The answer is use the scientific method. What is the Scientific Method? It is a series of steps used to help solve a problem.

Scientific Method  Step 1. Define the problem. Make sure only one problem is being studied. Step 2. Research the problem. Use all available resources to collect data on the subject being covered. Libraries, Internet, books, magazines, personal interviews, etc. Step 3. Develop a hypothesis (educated guess). Make it a short definitive statement. It should be an "if" then" statement. The “if” part will become the hypothesis and the then part should be the results received at the end of the controlled experiment. Remember your hypothesis can be changed it is not formed in concrete.

Scientific Method Cont. Step 4. Develop a controlled experiment. A controlled experiment is an experiment that contains only one experimental variable. An experimental variable is the thing being tested. Everything else in the experiment or all other variables must be the same. These variables are also called the controlled variables. Keeping these variables the same allows the experimenter to show that it was the experimental variable that caused the results.

Scientific Method Cont. Step 5. Analyze the data and come up with a conclusion. The conclusion may or may not support the hypothesis. Additional experimentation must then take place to build documentation concerning the problem. If the hypothesis is proven wrong, change the hypothesis, not the data.

Scientific Method Cont. Example: Problem: Research the problem:   Make a Hypothesis:   Develop a controlled experiment: Conduct the experiment & collect data: Form a conclusion based on the data: