Biology and You I. Themes of Biology Biology-the study of life

A. Living things share these PROPERTIES OF LIFE:  Cellular Structure and Function  Reproduction  Metabolism  Homeostasis  Heredity  Evolution  Interdependence

The Latin meaning of science is “to know”

1. Cellular Structure and Function All living things are made of one or more cells. Cells-smallest unit capable of all life functions

2. Reproduction  All living things can reproduce.  Bacteria can reproduce as fast as every 15 minutes.  Bristlecone Pines can be 5,000 years old and still be forming seeds.

3. Metabolism  Living things carry out many different chemical reactions in order to obtain and use ENERGY to run the processes of life.  Metabolism is the sum of all of the chemical reactions carried out in an organism.

3. Metabolism  Almost all the energy used by living organisms is originally captured from sunlight.  PHOTOSYNTHESIS is the process that plants, algae and some bacteria use to capture solar energy and use it to make food.  Energy flows from sun to plants, plants to plant-eaters, plant eaters to meat-eaters.

4. Homeostasis  All organisms must maintain a stable internal environment to function properly. This maintenance of stable conditions is called HOMEOSTASIS.  Examples: BODY TEMPERATURE, FLUIDS, PH, SUGAR LEVELS

5. Heredity  All living things are able to pass on traits to their offspring through genes that are passed from parent to offspring each generation.  A gene is the basic unit of heredity and are coded in a molecule called deoxyribonucleic acid (DNA).  The passing of traits from parent to offspring is called heredity.  Mutation –a change in the DNA of a gene  Example: Sickle Cell Anemia

6. Evolution  Change in the inherited traits of species over generations is called evolution.  Species is a group of genetically similar organisms that can produce fertile offspring.  Charles Darwin- 19th century naturalist known as the father of evolution; provided a consistent explanation for life’s diversity.  Natural Selection is the process in which organisms with favorable genes are more likely to survive to reproduce

7. Interdependence  Organisms in a biological community live and interact with other organisms.  Ecology-the branch of biology that studies the interactions of organisms with one another and with the nonliving part of their environment.

. Biology and Your World What world problems are biologists working to solve? What world problems are biologists working to solve?

Preserving Our Environment  Conservation and Preservation are now everyday activities of government, industry and individuals.

Improving Food Supply  One of greatest impacts of modern biology on society in recent years has been the genetic engineering of crop plants.  Genetic engineering has made some crop plants resistant to herbicides, some crop plants poisonous to insect pests, but not humans and has produced new varieties of crop plants.

Understanding the Human Genome  June 26, 2000: the announcement of the completion of the sequencing of the human genome.  A genome is the complete genetic material contained in an individual.  The human genome contains 3 billion individual units. 3 billion individual units.

Fighting Disease  AIDS-caused by HIV; destroys and attacks the immune system.  Cancer- a growth defect in cells.  3. Emerging Diseases- West Nile Virus is transmitted by mosquitoes and is known to infect humans, birds, horses, and other animals.  Mad Cow Disease is a caused by eating the body parts of infected animals.

Fighting Disease  Gene Therapy- Searching for ways to introduce “healthy” genes into people that are suffering from hereditary disorders.  a. Cystic Fibrosis-a fatal disorder in which mucus clogs passages in many of the body’s organs.  b. Gene Therapy-the replacement of a defective gene with a normal version.

 Steps to the Scientific Method –Title –Question/Problem –Research –Hypothesis/Prediction –Experiment/Test  Control, Independent & Dependent Variable –Data/Analysis –Conclusion

III. Scientific Processes  A. Solving Scientific Puzzles  OBSERVATION- the act of noting or perceiving objects or events using the senses.

B. Stages of Scientific Observations  1. Collecting Observations  2. Asking Questions  Talk to other scientists, read scientific reports  3. Forming Hypotheses  Hypothesis is an explanation that might be true- a statement that can be tested by additional observations.  Prediction is the expected outcome of a test.

Stages of Scientific Observations Con’t  4. Confirming Predictions  Experiment is a planned procedure to test a hypothesis.  Control Group is a group in the experiment that receives NO experimental treatment.  Independent variable is what is changed in an experiment.  Dependent variable is the variable that is measured in the experiment.

Stages of Scientific Observations Con’t  5. Drawing Conclusions  The hypothesis may be accepted or rejected.

Scientific Explanations- The Development of a Theory  A theory is a set of related hypothesis that have been tested and confirmed many times by many scientists.  A theory unites and explains a broad range of observations.