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Biology & You Chapter 1
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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.
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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
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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
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7 themes of biology 1.Cellular structure & function 2.Reproduction 3.Metabolism 4.Homeostasis 5.Heredity 6.Evolution 7.Interdependence (ecology)
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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.
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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.
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Feeding a growing population Genetically engineered crops are more resistant to disease and insects. Reduce the need for insecticides. Increase crop yields.
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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.
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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.
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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….
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Asking questions Questions are formed from careful observations and are the basis for forming hypothesis and making predictions.
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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.
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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.
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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.
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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/
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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.
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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.
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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.
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