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Chapter 1 A View of Life

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Chapter 1 A View of Life

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    1. Chapter 1 A View of Life Introduction to College Biology

    2. What does Biology have to do with Me? What is biology? How does it affect you? Where will you find biologists?

    4. Summary 3 Major themes of biology addressed in text Characteristics of Life Organization of living organisms Science and How Biologists Work Evolution Taxonomy The tree of life Natural selection

    5. 3 Major Themes in Biology Evolution Information transfer DNA Hormones and neurotransmitters Electrical Energy for life Sun ? producers (autotrophs) ? consumers (heterotrophs) ? decomposers (heterotrophs)

    6. Characteristics of Living Organisms Composed of cells Cell Theory part 1 – the cell is the fundamental unit of life. Unicellular/multicellular Prokaryotes/Eukaryotes

    7. Prokaryote vs Eukaryote

    8. Characteristics of Living Organisms Grow and develop Increase in size Exhibit structural and functional changes throughout life Regulate their own metabolic processes Metabolism = sum of all chemical activities Homeostasis = maintaining a stable internal environment despite changes in the external environment. Negative feedback mechanisms Positive feedback mechanisms

    9. Homeostasis Negative feedback Internal conditions have a normal value or range of values = set point. Variations from the set point stimulate a … Sensor that relays this information to the… Integration center that evaluates the information and sends instructions, if necessary, to an… Effector that corrects the problem and eliminates the signal to the sensor.

    11. Homeostasis Positive feedback Used sparingly in living things. Stimulus – integrations center - effector. In this case the effector does not eliminate the stimulus to the sensor; the physiological mechanism is amplified. Ex. Blood clotting, labor. Turned off by external event.

    12. Characteristics of Living Things Respond to stimuli Name some stimuli. How do organisms respond?

    13. Characteristics of Living Organisms Reproduce themselves Cell theory part 2 – all cells come from preexisting cells. Asexual and sexual

    14. Characteristics of Living Organisms Populations evolve and adapt to the environment. Adaptation involves characteristics that are inherited, i.e. genetic changes. Primary driving forces: Eating Avoiding being eaten Reproducing

    16. Process of Science Deductive reasoning draws specific conclusions based on general information (facts). Inductive reasoning draws general conclusions based on specific observations.

    17. How Do Biologists (Scientists) Work Scientific Method Observation Question or problem Hypotheses Testable predictions Experiments Analysis of data Conclusions

    18. Scientific Method Hypothesis Tentative explanation for observations Can be tested Can be rejected Prediction – using deductive reasoning to express the hypothesis in a way that can be tested. Experiments – testing predictions Best – test one variable at a time (variable is something that can be changed). Involve at least 2 groups

    20. Scientific Method Control groups Negative control – similar to experimental group but without the variable. Also called blank or zero. Positive control – similar to experimental group but does contain the variable. In quantitative analysis these become standards.

    21. Scientific Method Analyze data from several experiments. Conclusion(s): is hypothesis true or false? PUBLISH**** Consistent data by several investigators may lead to a ….

    22. Scientific Theory An explanation of natural world phenomena. Based on testable hypotheses. Supported by reproducible observations, i.e many scientists have the same conclusions. 2 components: Pattern – what is observed; the facts Process – how it happened

    23. Theory of Evolution Pattern: Populations change over time. Some species have become extinct. Observed by many scientists Process: natural selection Charles Darwin and Alfred Russel Wallace

    24. Natural Selection Applies to populations not individuals Darwin’s 4 Observations: Individuals in a population vary. More offspring are produced than survive long enough to reproduce. Organisms compete for resources; some are better adapted to succeed. Individuals that adapt most successfully survive to reproduce. Genetic variation through sexual reproduction and mutation fuels natural selection and evolution.

    26. Organizing the Study of Life Systematics - study of organisms and their evolutionary advances. Results often presented as “trees”. Taxonomy – Science of naming and classifying organisms. Classifying begins with the group or taxa with the smallest number of different individuals, the… Species – populations capable of breeding with one another.

    27. Taxonomy Carolus Linneaus – father of modern day taxonomy; created binomial nomenclature. Binomial nomenclature = two name system for all organisms, genus and species. Also began the classification of living organisms.

    28. Taxonomic Classification Today Domain Kingdom Phylum Class Order Family Genus Species

    29. 3 Domains and 6 Kingdoms Bacteria Kingdom - Bacteria Archaea Kingdom - Archaea Eukarya Kingdoms – Protista, Plantae, Fungi, Animalia NOTE: Both bacteria and archaea are prokaryotes all of the others are eukaryotes.

    30. Tree of Life

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