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Chapter 01 Lecture Outline
See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes and animations. 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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**Important study hint**
Review the study hints at the end of the syllabus. Multitasking does NOT work! Eliminate distractions while studying. Don’t watch TV Don’t text or watch for texts. Turn off your phone. Don’t log in to social media. Don’t or use social media in class. Follow link
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The Science of Biology Chapter 1 3
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The Science of Life Biology unifies much of natural science
Life defies simple definition Living systems are the most complex chemical systems on Earth Life is constrained by the properties of chemistry and physics Science is becoming more interdisciplinary Combining multiple fields 4
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The Science of Life 7 characteristics of all living organisms
Cellular organization Ordered complexity Sensitivity Growth, development, and reproduction Energy utilization Homeostasis Evolutionary adaptation – at population level 5
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The Science of Life Living systems show hierarchical organization
Cellular level Organismal level Populational level Ecosystem level Biosphere 6
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The Science of Life Living systems show hierarchical organization
Cellular level Atoms, molecules, organelles, cells Cell is the basic unit of life Atoms Molecule Macromolecule CELLULAR LEVEL Organelle Cell 0.2 µm O C H N 7
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Cellular Level 8 Atoms Molecule Macromolecule CELLULAR LEVEL Organelle
H N 8 (organelle): © Dr. Donald Fawcett & Porter/Visuals Unlimited; (cell): © Steve Gschmeissner/Getty Images Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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The Science of Life Living systems show hierarchical organization
Organismal level Tissues, organs, organ systems individual organism Tissue Organ ORGANISMAL LEVEL Organ system Organism 9
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(tissue): © Ed Reschke; (organism): © Russell Illig/Getty Images RF
Organismal Level Tissue Organ ORGANISMAL LEVEL Organ system Organism PM: fix centering of col. Headings? 10 100 µm (tissue): © Ed Reschke; (organism): © Russell Illig/Getty Images RF Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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The Science of Life Living systems show hierarchical organization
Populational level Population (interbreeding) Community (all populations within a habitat) Ecosystem level Biosphere Earth is an ecosystem we call the biosphere POPULATIONAL LEVEL Population Species Community Ecosystem Biosphere 11
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Populational Level 12 POPULATIONAL LEVEL Population Species Community
Ecosystem Biosphere PM: alphas correct as set with photo source if not set w/art? Pl. confirm thru-out (population): © George Ostertag/agefotostock; (species): © PhotoDisc/Volume 44 RF; (community): © Ryan McGinnis/Alamy; (ecosystem): © Robert and Jean Pollock; (biosphere): NASA 12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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The Science of Life Each level has emergent properties
Result from interaction of components Cannot be deduced by looking at parts themselves – “whole is greater than the sum of the parts” “Life” is an emergent property Populational correct as set? 13
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The Nature of Science Science aims to understand the natural world through observation and reasoning Science begins with observations, therefore, much of science is purely descriptive Classification of all life on Earth Human genome sequencing 14
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The Nature of Science Science uses both deductive and inductive reasoning… Deductive reasoning uses general principles to make specific predictions (big idea specific situation) Inductive reasoning uses specific observations to develop general conclusions (specific observations big idea) 15
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The Nature of Science Scientists use a systematic approach to gain understanding of the natural world = Scientific Method Observation Hypothesis formation Prediction Experimentation Conclusion 16
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Note the use of alternative hypotheses
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Observation Note the use of alternative hypotheses Question Hypothesis 1 Hypothesis 2 Reject hypotheses 1 and 4 Potential hypotheses Hypothesis 3 Experiment Hypothesis 4 Hypothesis 5 Remaining possible hypotheses Hypothesis 2 Reject hypotheses 2 and 3 Hypothesis 3 Experiment Hypothesis 5 Last remaining possible hypothesis Hypothesis 5 Modify hypothesis Predictions Experiment 1 Experiment 2 Experiment 3 Experiment 4 Predictions confirmed 17
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The Nature of Science A hypothesis is a possible explanation for an observation – NOT just an “educated guess” A hypothesis (the “if”) Must be able to be tested to determine its validity Allows for predictions to be made if hypothesis is true Is often tested in many different ways Iterative Hypotheses can be changed and refined in light of new data “If this…then…” 18
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The Nature of Science Predictions (the “then”)
Valid hypotheses must provide testable predictions Predictions provide a way to test the validity of hypotheses, … Hypothesis must be rejected if the experiment produces results inconsistent with the predictions The more experimentally supported predictions a hypothesis makes, the more valid the hypothesis “If this…then…” 19
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The Nature of Science Experiment Tests the hypothesis thru predictions
Must be carefully designed to test only one variable at a time Consists of a test treatment(s) and a control(s) Must have replication Results must be reproducible Control (0 mg drug) 1 mg drug 2 mg drug 4 mg drug 20
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Copyright © The McGraw-Hill Companies, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. SCIENTIFIC THINKING Test: Use swan-necked flasks to prevent entry of microorganisms. To ensure that broth can still support life, break swan-neck after sterilization. Question: Broken neck of flask Flask is sterilized by boiling the broth. Unbroken flask remains sterile. Broken flask becomes contaminated after exposure to germ-laden air. Conclusion: Growth in broth is of preexisting microorganisms. What is the source of contamination that occurs in a flask of nutrient broth left exposed to the air? Germ Hypothesis: Preexisting microorganisms present in the air contaminate nutrient broth. Prediction: Sterilized broth will remain sterile if microorganisms are prevented from entering flask. Spontaneous Generation Hypothesis: Living organisms will spontaneously generate from nonliving organic molecules in broth. Prediction: Organisms will spontaneously generate from organic molecules in broth after sterilization. Result: No growth occurs in sterile swan-necked flasks. When the neck is broken off, and the broth is exposed to air, growth occurs. Note that the alternative hypotheses have different (mutually exclusive) predictions 21
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The Nature of Science Complimentary philosophical approaches to science Reductionism To break a complex process down to its simpler parts Systems biology Focus on emergent properties that can’t be understood by looking at simpler parts 22
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The Nature of Science Models in science Way to organize thought
The Nature of Science Models in science Way to organize thought Parts provided by reductionist approach Model shows how they fit together Suggest experiments to test the model Mathematical, graphical, computer 23
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The Nature of Science Scientific theory – more than “just a theory”
Body of interconnected concepts Supported by much experimental evidence and scientific reasoning Expresses ideas of which we are most certain Compare to general meaning of theory Implies a lack of knowledge or a guess 24
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Darwin and Evolution Example of how a scientist develops a hypothesis and a theory gains acceptance Charles Darwin served as naturalist on mapping expedition around coastal South America 30 years of observation and study before publishing On the Origin of Species by Means of Natural Selection 25 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Voyage of the HMS Beagle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. NORTH PACIFIC OCEAN Marquesas Society Islands Straits of Magellan Cape Horn Tierra del Fuego SOUTH ATLANTIC New Zealand Hobart King George’s Sound Mauritius Bourbon Island Philippine British Isles Western Isles EUROPE ASIA Madagascar Friendly Equator AMERICA Galápagos Cape Verde Canary AFRICA Sydney AUSTRALIA INDIAN Cape of Good Hope Falkland Valparaiso Port Desire Buenos Aires Montevideo Keeling Bahia Ascension St. Helena Rio de Janeiro 26
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Darwin and Evolution Darwin was not the first to propose evolution
It was known that living things have changed over time Darwin’s contribution was a mechanism for evolution Natural selection 27
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Darwin and Evolution On the Beagle, Darwin saw that characteristics of similar species varied from place to place Galápagos Finches 14 related species differ only slightly “Descent with modification” or evolution Woodpecker Finch (Cactospiza pallida) Large Ground Finch (Geospiza magnirostris) Cactus Finch (Geospiza scandens) 28 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Darwin and Evolution Darwin studied Thomas Malthus’s An Essay on the Principle of Population Populations of plants and animals increase geometrically (multiplicative, example x3) Humans can only increase their food supply arithmetically (additive, example +2) Populations of species remain constant because death limits population numbers 29
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Darwin and Evolution Darwin saw that:
Every organism has the potential to produce more offspring But, only a limited number survive and reproduce themselves Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. geometric progression arithmetic progression 54 Human Growth is Geometric Human food production is Arithmetic 18 6 8 2 6 4 30
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Darwin and Evolution Darwin made an important association:
Individuals with attributes that give them an advantage in their environment are more likely to survive and reproduce Pass these characteristics on to their offspring The population will gradually change over time Darwin called this selection
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Darwin and Evolution Evidence supporting Darwin’s theory has only grown Fossil record Earth’s age Mechanism for heredity Comparative anatomy Molecular evidence 32
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Darwin and Evolution Evidence supporting Darwin’s theory has only grown Fossil record Transitional forms have been found at predicted positions in time Earth’s age Physicists of Darwin’s time were wrong Earth is very old – 4.5 billion years old 33 Image by B. Tyler
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Darwin and Evolution Evidence supporting Darwin’s theory has only grown Mechanism for heredity Mendel’s laws of inheritance were unknown to Darwin At time of Darwin there was no concept of “genes” or how heredity worked Darwin could not completely explain how evolution worked Now have detailed understanding of heredity 34
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Darwin and Evolution Evidence supporting Darwin’s theory has only grown Comparative anatomy Vertebrate forelimbs all share the same basic array of bones Homologous – same evolutionary origin but now differ in structure and function (forelimbs of verts) Analogous – structures of different origin used for the same purpose (butterfly and bird wings) Human Cat Porpoise Horse Bat 35
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Darwin and Evolution Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Human Cat Porpoise Horse Bat Homologous – same evolutionary origin but now differ in structure and function 36
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Darwin and Evolution Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Evidence supporting Darwin’s theory has only grown Molecular Evidence Compare genomes or proteins of different organisms Phylogenetic trees – based on tracing origin of particular nucleotide changes to reconstruct an evolutionary history Human Rhesus Dog Bird Frog 10 20 30 40 50 60 70 Number of Amino Acid Differences in a Hemoglobin Polypeptide 37
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Unifying Themes in Biology
Cell theory All organisms composed of cells Cells are life’s basic units All cells come from preexisting cells a. b. 60 µm 500 µm Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Dennis Kunkel/Phototake; b: © Karl E. Deckart/Phototake 38
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Unifying Themes in Biology
Molecular basis of inheritance Deoxyribonucleic acid (DNA) Sequence of 4 nucleotides encode cell’s information Gene – discrete unit of information Genome – entire set of DNA instructions Continuity of life depends on faithful copying of DNA into daughter cells 39
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Unifying Themes in Biology
Structure and function Study structure to learn function Know a function – look for that structure in other organisms Example Receptor on human cell for insulin known Find similar molecule in a worm Might conclude this molecule functions the same in the worm 40
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Unifying Themes in Biology
Diversity of life arises by evolution Underlying unity of biochemistry and genetics argues for life from the same origin event Diversity due to evolutionary change over time 3 domains of life Bacteria – single-celled prokaryote Archaea – single-celled prokaryote Eukarya – single-celled or multicellular eukaryote Know these! 41
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Know the kingdoms! Domain Kingdoms 42 Plantae Fungi Eukarya Animalia
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Domain Kingdoms Plantae Know the kingdoms! Fungi Eukarya Animalia Protista (plantae middle): © David M. Dennis/Animals Animals; (plantae right): © Corbis/Volume 46 RF; (fungi left): © Royalty Free/Corbis; (fungi middle): © Mediscan/Corbis; (fungi right): © PhotoDisc BS/Volume 15 RF; (animalia left): © Royalty-Free/Corbis; (animalia middle): © Tom Brakefield/Corbis; (animalia right): © PhotoDisc/Volume 44 RF; (protista left): © Corbis/Volume 64 RF; (protista middle): © Tom Adams/Visuals Unlimited; (protista right): © Douglas P. Wilson/Frank Lane Picture Agency/Corbis 42
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Unifying Themes in Biology
Evolutionary conservation All organisms today descended from a simple creature 3.5 BYA Many characteristics preserved Ex: use of DNA Conservation reflects that they have a fundamental role in life Evidence for evolution Tree of Life 43
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Unifying Themes in Biology
Cells are information-processing systems Information in DNA used to direct synthesis of cellular components Control of gene expression leads to different cells/ tissue types Cells process environmental information Glucose levels, presence of hormones Cells in multicellular organisms must coordinate with each other 44
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Cells to ecosystems are open
Unifying Themes in Biology Nonequilibrium state Living systems are open systems Constant supply of energy needed Self-organizing properties at different levels Emergent properties from collections of molecules, cells, and individuals Cells to ecosystems are open 45
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