Chapter 1: Biology and You Section 1: Themes of Biology Objectives: Relate the seven properties of life to a living organism. Describe seven themes that can help you organize what you learn about biology. Identify the tiny structures that make up all living organisms. Differentiate between reproduction and heredity and between metabolism and homeostasis.
Characteristics of Living Organisms Biology is the study of life. o All living organisms share certain general properties that separate them from nonliving things. o Seven Properties of Life . Cellular organization - every living thing is composed of one or more cells . Reproduction - all living things are able to reproduce . Metabolism - all living things obtain and use energy to run the processes of life . Homeostasis - living organisms maintain a consistent internal environment . Heredity - living things pass traits to offspring . Responsiveness - all living things respond and adjust to the environment . Growth and development - all living things grow and develop Unifying Themes of Biology (different from the properties of life) 1. Cellular Structure and Function o Cells are highly organized, tiny structures with thin coverings called membranes. All living things are made of one or more cells. A cell is the smallest unit capable of all life functions. 2. Reproduction o Reproduction is the process by which organisms make more of their own kind from one generation to the next. 3. Metabolism o Metabolism is the sum of all the chemical reactions carried out in an organism. Almost all energy used by living organisms is originally captured from sunlight. 4. Homeostasis o Homeostasis is the maintenance of stable internal conditions in spite of changes in the external environment. An organism unable to balance its internal conditions with its environmental conditions could become ill and die.
5. Heredity o Heredity is the passing of traits from parent to offspring. The basic unit of heredity is called a gene. Genes are coded in a molecule called deoxyribonucleic acid (DNA). Genes determine an organism’s traits. A change in the DNA of a gene is called a mutation. Most mutations are harmful, but some mutations can help an organism survive. 6. Evolution o Evolution is defined as change in the inherited characteristics of species over generations. A species is a group of genetically similar organisms that can produce fertile offspring. Natural selection is the process in which organisms with favorable traits are more likely to survive and reproduce. 7. Interdependence o The organisms in a biological community live and interact with other organisms. Ecology is the branch of biology that studies the interactions of organisms with one another and with the nonliving part of their environment. Organisms are dependent on each other and on their environment.
Unifying Themes of Biology Properties of Life
Seven themes. Seven Properties.
1.Cellular Structure and Function 1. Cellular organization
2.Reproduction 2. Reproduction
3.Metabolism 3. Metabolism
4.Homeostasis 4. Homeostasis
5.Heredity 5. Heredity
6.Evolution 6. Responsiveness
7.Interdependence 7. Growth and development
Section 3: Scientific Processes Objectives: Describe the stages common to scientific investigations. Distinguish between forming a hypothesis and making a prediction. Differentiate a control group from an experimental group and an independent variable from a dependent variable. Define the word theory as used by a scientist. *The term scientific method comes from the definition of science as "knowledge" and the Greek word methodos, meaning "pursuit" or "going after."
The Scientific Method: Is "organized common sense" Is a way to obtain information. (Data) Is logical. Uses problem solving skills in an orderly manner.
Steps to follow in using the scientific method:
1. Define the problem by making observations. (Remember: question from….)
2. Research the problem
3. Form a hypothesis. "An Educated Guess"
4. Conduct an esperiment. 5. Make and record observations. 6. Analyze data. 7. Draw conclusions. (Answer your problem.) 8. Communicate results.(Report your results) 9. After many studies… Theory – set of related hypotheses that have been tested and
confirmed many times by many scientists. Objective: Identify controls &variables in an experiment.
Experiment - an organized procedure or method to test a hypothesis. Control - a standard for comparison o No variable. (Ex. plain water) Constants - factors that do not vary (do not change) in an experiment. o They must remain the same. (Ex. brand, height....) Independent variable - factor changed by the experimenter (the factor tested) - a good experiment tests one variable. Dependent variable - factor that depends on the value of the independent variable (a result measured) When graphing: Y - axis
Dependent
variable
here
X- axis
Independent variable here
Facts about controlled experiments:
1. The more times you do an experiment, the more dependable the results.
2. The larger the size of the experimental group, the more accurate the results.
3. Your hypothesis (educated guess) should be as specific as possible.
4. The procedures you use in an experiment must be as quantitative as possible.
5. All controls in an experiment must be kept the same.
*No control experiment invalid.
6. Only one variable can be tested in an experiment, otherwise the experiment becomes invalid.
Goal: Demonstrating observation as a tool for solving problems.
Observations are:
Information (data) gathered by using our senses. - seeing, hearing, touching, smelling, and tasting. There are 2 kinds of observations: 1. Quantitative 2. Qualitative
Quantitative Observations
About numbers A measurement How much? (quantity) Example: "20 drops" of water, length (meters), volume (liters), mass (grams), temperature ( Celsius)
Qualitative Observations
Anything but numbers Describe a property or characteristic (quality) o Example: Color, shape, form of matter (solid, liquid, gas)