Biology & You Chapter 1

1-1 Themes of Biology Learning results:  Relate the 7 properties of life to living things.  Describe the 7 themes of biology.  Identify the tiny structures that make up all living things.  Differentiate between reproduction & heredity and metabolism & homeostasis.

Living organisms have certain characteristics Biology; Bio-, Life -logy, study of The study of life Biologist Bio- -logy - ist, specialist Person who specializes in the study of life

7 characteristics of life 1. Cellular organization: all living things are composed of cells. 2. Reproduction: ability to reproduce. 3. Metabolism: Obtain & uses energy for life processes 4. Homeostasis: Maintain constant internal environment 5. Heredity: Pass trait to offspring 6. Responsiveness: Respond to environment 7. Growth & development

7 themes of biology 1.Cellular structure & function 2.Reproduction 3.Metabolism 4.Homeostasis 5.Heredity 6.Evolution 7.Interdependence (ecology)

1-2 Biology & your world Learning results:  Evaluate the role biologists play in saving our tropical forests.  Describe the role biologists play in trying to increase & improve our food supply.  Describe efforts to combat diseases that are subject of current scientific research.

Living in harmony with your environment  Environmental ecology of rainforest:  hold more plant & animal species than any other biome area.  Human impact: destroyed at an acre per second.

Feeding a growing population  Genetically engineered crops are more resistant to disease and insects.  Reduce the need for insecticides.  Increase crop yields.

Help Fight disease  HIV/Aids: virus that destroys immune system.  Drugs to fight virus and stop it’s spread  Cancer: Uncontrolled cell division  Pacific Yew tree contains taxol, a anticancer chemical used to treat ovarian & breast cancers.  Stem cells  Cystic Fibrosis: Lungs have abnormally thick mucous build up caused by defective gene.  Gene replacement therapy can cure the person inflicted with disease.

1-3 The scientific process Learning results:  Describe stages common to scientific experimentation.  Distinguish between forming a hypothesis & making a prediction.  Differentiate a control group from an experimental group and an independent variable from dependant variable.  Define the word theory.

Observation  The act of noting or perceiving objects or events using the senses.  Qualitative observation: qualities of the object.  The object smells like, tastes like, feels like, sounds like, looks like…..  Quantitative observation: comparing an object/event to a standard or non standard measurement.  The object is 6 feet tall, weighs 300kgs, is 5 hands wide….

Asking questions  Questions are formed from careful observations and are the basis for forming hypothesis and making predictions.

Forming Hypotheses & making predictions  An explanation that might be true and can be tested.  Predictions are the expected outcome of a test assuming the hypothesis is correct.

Experimentation  A planned procedure to test a hypothesis  Control group: receives no experimental treatment  Independent variable: variable that will be changed or tested.  Dependant variable: variable that is measured.

Collect data & draw conclusions  The hypothesis is either supported or rejected.  Supported hypothesis give support to scientific theories.  Theories unite a broad range of observations. A generally accepted principle.

Salamander experiment  Observation:  Observed salamander population decreasing  Observed a 65% decrease in population.  Questions:  What was causing the population decrease?  Was acid rain causing the decrease?  Hypothesized:  that acids formed in the upper atmosphere were falling a s snow.  Melting snow caused the pH level in the ponds to increase effecting the salamander embryos/

 Experiment:  Captive salamanders laid eggs in regular pond water. Eggs divided into 5 groups.  Control: eggs out in neutral pH pond water.  4 groups placed in water at varying pH levels.  Independent variable: pH level (acidity) of water  Dependant variable: number of healthy salamanders born.

 Data collection  Many salamanders did not hatch in acidic water and those that did had abnormalities.  Conclusion:  Pond water became more acid after snow melted.  Acidic water reduces the birthrate of health salamanders.

Summary  Scientists add to scientific knowledge by sharing observations.  Observing, asking questions, and forming and testing hypotheses are important in planning scientific experiments.  In a controlled experiment, the independent variable is varied between the experimental and control group.  The measured variable is the dependent variable.  A collection of hypotheses that have been repeatedly tests and supported form the basis for scientific theory.