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Bio 178 Lecture 1 Biology: The Study of Life
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Reading Chapter 1 Quiz Material Questions on P18 Chapter 1 Quiz on Text Website (www.mhhe.com/raven7)
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Outline Definition of Biology Properties of Life Hierarchical Organization Scientific Method Unifying Themes of Biology
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What is Biology? The scientific study of organisms (living beings).
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Properties of Life Basic characteristics of living organisms –Cellular Organization –Order –Sensitivity –Growth, Development, and Reproduction –Energy Utilization (metabolism) –Evolutionary Adaptation –Homeostasis
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Hierarchical Organization Cellular level –Atoms –Molecules –Macromolecules –Organelles –Cells Organismal level –Tissues –Organs –Organ systems –Organisms
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Hierarchical Organization Populational level –population species –biological community »ecosystem –Emergent properties Novel properties that arise at each higher level
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The Scientific Method: The Hypothetico-Deductive Method Hypothesis - Tentative answer to a question (educated guess) Deductive - Deductive Reasoning Reasoning Deductive Reasoning (Predictions) –Apply general principles to predict specific results Eg. “If organisms are composed of cells (H 1 ) & humans are organisms (H 2 ), then humans are composed of cells (P)”. Inductive reasoning –Use specific observations to construct general principles
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Stages of a Scientific Investigation Observation Question Hypothesis(es) Prediction(s) Controlled Experiment Conclusion
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How to Write QHPs Example 1: The laptop stops working. O: The laptop is not working Q: Why is the laptop not working? H: Example 2 (include a control): Asprins get rid of headaches. Q: Do asprins truly get rid of headaches? H: If asprins truly get rid of headaches, the headaches will clear FASTER if asprin is taken than if it is not. Controlled Experiment: Predictions: Conclusions:
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A Few Definitions An experiment is used to test a hypothesis, and/or eliminate one or more multiple hypotheses. In a controlled experiment, all variables but one are kept constant in the experimental. In the control that variable is unaltered. A theory is a hypothesis supported by a wealth of scientific evidence ( is a generally accepted principle).
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Scientific Process O Q H P Controlled Experiments Conclusions Manuscript preparation for publication Peer Review Publication Replication by other scientists Acceptance by the scientific community
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Example of the Development of a Theory: Evolution Accepted “Belief” in 1831: Species have been specifically created and are unchangeable over time. Darwin’s Evidence: Fossil record Geographical Distribution Islands Darwin’s Theory:Evolutionary changes occurring by the mechanism of natural selection are responsible for the diversity of life on earth.
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Unifying Themes of Biology Cell theory Molecular basis of inheritance Evolutionary change - Diversity Evolutionary conservation - Successful structures are conserved
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Cell Theory Robert Hooke (1665): Discovered cells Schleiden and Schwann (1839): “All living things are composed of cells” Modern Cell Theory All living organisms are made of cells, and all living cells come from other living cells. Unifying Themes in Biology
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Unifying Themes of Biology Molecular basis of inheritance –DNA encodes genes which make-up and control living organisms. Heredity is dependent on the faithful copying of the cell’s DNA into daughter cells. Evolutionary conservation – Some fundamentally important characteristics of earlier organisms are preserved and passed on to future generations. Eg. Histones
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Unifying Themes of Biology Evolutionary change –Life-forms have evolved varying characteristics to adapt to varied environments. This has resulted in incredible diversity.
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