BIOL1152-02_Handouts_Part_1.pdf

BIOL1152-02 Fall 2024 MSVU BIOL1152 02 Handouts Part 1 - Introduction...

BIOL1152-02 Fall 2024 MSVU BIOL1152 02 Handouts Part 1 - Introduction - How Science Works - Diversity and Evolution 1 BIOLOGY Greek: Bios (“life”) and Logos (“meaning”) The Study of Life and Living Organisms! 2 Copyrighted Material for In-class Use! No Publication or Distribution! 1  BIOL1152-02 Fall 2024 Biology as a Science! Biology is the “youngest” of Natural Sciences, even if it has been part of human life for thousands of years Since When? 3 BIOLOGY = Greek bios – life & logos – knowledge Science of Life Modern Biology: - “Youngest” and Most Interdisciplinary of the Natural Sciences - Chemistry - Physics - Statistics/Mathematics - Computer science A Chemist can do chemistry without knowing biology A Physicist can do physics without knowing biology A Mathematician / Statistician can work without knowing biology Biologists Must Know Some Chemistry, Physics, Math and Stats otherwise, they do not get far 4 Copyrighted Material for In-class Use! No Publication or Distribution! 2  BIOL1152-02 Fall 2024 Since the 19th Century (e.g., 1800s) Biology as a Science Has Been On The Fast Track! Alexander von Humboldt (1769 – 1859) Charles Darwin (1809 – 1882) Gregor Mendel (1822 – 1884) Louis Pasteur (1822 - 1895) Jean-Henri Fabre (1823 – 1915) New Technologies, New Methods, New Ways of Thinking Lead to Leaps in Scientific Progress! 5 BIOLOGY = Greek bios – life & logos – knowledge Science of Life Modern Biology: - First boom in the 19th century, Second boom since the late 20th century - New Tools, Methods, Techniques, Ideas, Visions - Computer Technology (data analysis) - Molecular Biological Methods - Genome Databases - Antibody based Immunohistology - Imaging Techniques - Genetic Engineering 6 Copyrighted Material for In-class Use! No Publication or Distribution! 3  BIOL1152-02 Fall 2024 What is Science? A Brief Definition of Science and How Science Works! 7 SCIENCE = Latin knowledge Natural Sciences are mostly Descriptive and Empirical Sciences! Based on Gathering Evidence, looking for Explanations - by Observation - by Description of the Observed - by Interpretation of the Observed Goal of Science: Understand and Explain the World Around Us! Interpretation of collected evidence can be based on - Deductive Reasoning Both Are Valid and Used Approaches! - Inductive Reasoning 8 Copyrighted Material for In-class Use! No Publication or Distribution! 4  BIOL1152-02 Fall 2024 What is Science? Deductive Reasoning / Logic: If all premises are correct, the terms are clear, and the rules of deductive logic are followed, then the Conclusion Reached is Necessarily True. Example: All human are mortal. The pope is a human. Conclusion: Therefore, the pope is mortal. 9 What is Science? Inductive Reasoning / Logic: Even if all premises are true inductive reasoning still allows for the Possibility that the Conclusion is False. Example: Impact of a large asteroid impact creates a very large crater and has severe impact on weather that could drive heterotherms like non-avian dinosaurs to extinction. We observe a very large crater in the Gulf of Mexico that dates to the time of the mass extinction of the non-avian dinosaurs. Conclusion: Therefore, it is possible that this asteroid impact could explain why the non-avian dinosaurs became extinct. 10 Copyrighted Material for In-class Use! No Publication or Distribution! 5  BIOL1152-02 Fall 2024 What is Science? Natural Sciences like Biology are Empirical Sciences working by - Gathering Evidence (Observations) - Formulating a Hypothesis, i.e., a proposed and reasonable explanation for the observed phenomenon - Testing of a Hypothesis by doing experiments, where hypothesis should predict the outcome of the experiment - Accept or Reject Hypothesis depending on outcome of testing - Hypothesis Refinement, Modification, and Testing after Critical Analysis of Model or Theory Observed Outcome is Scientific Routine 11 What is Science? Cycle of Hypotheses Formulation, the Experimental Testing of Hypotheses, and Refinement is Scientific Routine! IMPORTANT! Results and Findings of Experiments and Outcome must be Reproducible by Fellow Scientists => concept of peer review However, Interpretation of Results can Differ and are up for critical review and discussion Interpretations Change Over Time, as new results and methods offer Model or Theory new insights. 12 Copyrighted Material for In-class Use! No Publication or Distribution! 6  BIOL1152-02 Fall 2024 What is Science and What is Not ? 13 The Scientific Hypothesis - Proposed, Tentative, and Testable Explanation for an Observed Phenomenon Challenge is to Design an Experiment Suitable to Test the Hypothesis Experiment and Results must be reproduceable, verifiable, and conclusive The Scientific Theory - Explanation of an Observed Phenomenon based on a Series of Scientific Hypotheses, all tested and verified The Scientific Model - Tool to Understand and Predict Observations based on Results and Conclusions Obtained in Experiments 14 Copyrighted Material for In-class Use! No Publication or Distribution! 7  BIOL1152-02 Fall 2024 Note: A Scientific Model Does Not Represent Reality! It may get close, but the predicted outcome may differ from observed outcome! 15 An Example How Science Works, and How Knowledge is Formed The Golgi/Cajal Dispute Reticularists vs Neuronists The Birth of Modern Neuroscience 16 Copyrighted Material for In-class Use! No Publication or Distribution! 8  BIOL1152-02 Fall 2024 NOBLE PRICE for Medicine 1906 Camillo Golgi Santiago Ramón y Cajal 1843 - 1926 1852 - 1934 - Started to study the central nervous system in the 1870s - Used the Same Methods and Technology - Observed the Same Structures - Interpreted Observation Very Differently and came to Very Different Conclusions Scientific Dispute! 17 NOBLE PRICE for Medicine 1906 Camillo Golgi Santiago Ramón y Cajal 1843 - 1926 1852 - 1934 Reticular Theory Neuron Doctrine - Nervous System is a Continuous - Nervous System is formed Meshwork, formed by Fusion of by Discrete cells (neurons) Cells into a Continuum, similar to Connecting into a Network, the vascular system not by Fusion Both had their fellowship (Reticularists vs. Neuronists) and both Theories were widely discussed within the scientific community 18 Copyrighted Material for In-class Use! No Publication or Distribution! 9  BIOL1152-02 Fall 2024 NOBLE PRICE for Medicine 1906 Camillo Golgi Santiago Ramón y Cajal 1843 - 1926 1852 - 1934 Limited by Available Tools and Methods the Discussion Remained Unresolved for another 50 years In the 1940s the Electron Microscope (new method!) showed Definitive Proof that Neurons connect with synapses and do not fuse into a continuum BUT, discovery of Electrical Synapses (“Gap Junctions”) in the 1950s showed that Golgi wasn’t entirely wrong 19 New Technologies, New Methods, New Ways of Thinking Lead to Leaps in Scientific Progress! - Microscopes and Histological Techniques - Electronics, Computer, and IT-Technology - Molecular Biology - Genetic Engineering - …….. 20 Copyrighted Material for In-class Use! No Publication or Distribution! 10  BIOL1152-02 Fall 2024 Take Home Message: Science and Research Are Work In Progress! Advances and Changes Happen All The Time! Dispute Between Scientist is Common and One Driving Force for Scientific Progress! 21 What is Science and What is Not? 22 Copyrighted Material for In-class Use! No Publication or Distribution! 11  BIOL1152-02 Fall 2024 Hunters and Animal/Plant Breeders of the Past: For ages successful, based on observations and experiences Hunters and Breeders = Scientists When did hunting (“wildlife management”) and breeding of animals and plants (“husbandry”) became Science? When turned “alchemy” into chemistry? When becomes a birdwatcher an ornithologist? 23 American Birding Association: Few thousand members, most observers and reporters Nova Scotia Bird Society: Few hundred members, most observers and reporters Birder, Birdwatcher = Ornithologist Scientists work to explain observations by: CITIZEN - Collecting Data SCIENCE - Analyzing Data SCIENCE - Interpreting Data RESEARCH SCIENCE - Formulating and Testing Hypotheses - Communication and Discussion of Findings and Conclusions with Peers 24 Copyrighted Material for In-class Use! No Publication or Distribution! 12  BIOL1152-02 Fall 2024 Common Misconceptions of the Nature of Science Hypotheses become Theories that eventually become Laws There is No such developmental sequence of scientific ideas, Scientific Theories are the Same as Scientific Laws! Scientific Laws and Theories are Absolute In science all is Tentative, self-correcting mechanisms are crucial elements of science! Scientific Knowledge Evolves! A Scientific Theory is an Advanced Idea A Scientific Theory is Result of Rigorous Testing and Discussion by many Scientists! A Hypothesis is an Educated Guess A Scientific Hypothesis is based on Careful Observation and Evidence Gathering, and it is Rigorously Tested! 25 Common Misconceptions of the Nature of Science Science Creates Sure Knowledge Scientific Knowledge stand Until Proven Otherwise, even before then scientific dispute is common! Science provides Absolute Proof Scientific Results are Tentative and Subjected to Revision When new Information is Arises! This information supports, validates and substantiates findings, but never proves them! Science is Objective Science is made by Scientists. Scientists are Humans. Humans are never Objective! Acceptance of New Scientific Knowledge is Straightforward Establishing new scientific knowledge – especially when crucially different from established paradigms – is daunting business. Gatekeepers have to be passed to find and reach listeners 26 Copyrighted Material for In-class Use! No Publication or Distribution! 13  BIOL1152-02 Fall 2024 Common Misconceptions of the Nature of Science Scientific Models Represent Reality Scientific Models are used to understand and explain complex systems by limiting parameters. A Scientific Model Represent the Reality of the Model! A model may come close to the reality, but adding or changing parameters in a model will create a new reality. 27 What is Science and What is Not ? 28 Copyrighted Material for In-class Use! No Publication or Distribution! 14  BIOL1152-02 Fall 2024 The Problems of Our Time: - Unfiltered Information Everyone can communicate instantly and globally to an unlimited -often naïve- audience - “Alternative” Facts Uncontrolled communication of non-vetted “facts” - Information Overload 10000s of self-declared “Experts” spread 10000000s of opinions - Redaction of False or Outdated Information Impossible The internet doesn’t forget, and people believe what fits their agenda and supports their views of the world - AI 29 What is Science and What is Not ? True Science: Based on Empirical Research and Testing of Hypotheses! Pseudo Science: Based on statements, beliefs, or practices that claim to be both scientific and factual but are in fact untested or untestable! BIG DIFFERENCE BETWEEN THE TWO: True Science: BURDEN OF PROOF is ALWAYS with the Claimant, Not with the Critic! 30 Copyrighted Material for In-class Use! No Publication or Distribution! 15  BIOL1152-02 Fall 2024 31 32 Copyrighted Material for In-class Use! No Publication or Distribution! 16  BIOL1152-02 Fall 2024 Modern Biology Most Interdisciplinary Science molecular biology molecular biology biochemistry molecular biology biochemistry cell biology neurochemistry cell biology neurobiology neurophysiology biophysics physiology neuroanatomy anatomy anatomy ethology neuroethology ethology ecology ecology 33 Life can be Studied on Different Levels of Complexity! - Population Level: From interaction between individuals to ecosystems - Organismal Level: From interaction between cells to organism - Cellular Level: From cellular functions to cellular interactions - Sub-Cellular Level: From molecules to molecular interaction and cellular functions. 34 Copyrighted Material for In-class Use! No Publication or Distribution! 17  BIOL1152-02 Fall 2024 Studying Life = Studying Diversity - Biology Started Out Cataloging and Describing the Diversity of Life on Earth - Understanding the Origin of Diversity - Understanding How Life Works 35 Biology = Studying The Diversity of Life “How many distinct life forms—species—does your planet have? Embarrassingly, our best-guess answer would be in the range of 5 to 10 million eukaryotes (never mind the viruses and bacteria), but we could defend numbers exceeding 100 millions” (R. May (2010), Science 329, 41-42) 36 Copyrighted Material for In-class Use! No Publication or Distribution! 18  BIOL1152-02 Fall 2024 Sorting, The First Step To Bring Order Into Chaos Order Allows To Study Systematically What Is Otherwise Hidden And Hard To See We Sort By Similarities And By Looking For Relationships ©Ursus Wehrli 37 38 Copyrighted Material for In-class Use! No Publication or Distribution! 19  BIOL1152-02 Fall 2024 Taxonomy and Phylogeny: Branches of the Tree of Life Current Taxonomy, “Tree of Life” based on “Systema Naturae” ,developed by Carolus Linnaeus (1707- 1778) - Classification and Sorting of Living Organisms by Morphological Features (observable) - Grouping of Organisms in Hierarchical System with Increasing Inclusiveness Sorting Helps to Put Some Sense into Chaos! 39 Categorizing the Living World Around Us Living Organisms categorized in Three DOMAINS - Archaea (aka archaebacteria) Prokaryotes - Bacteria - Eukarya Eukaryotes Prokaryotic Cells Do Not Have a Nucleus (DNA free in cytoplasm) Eukaryotic Cells Have a Nucleus (DNA contained in nucleus) 40 Copyrighted Material for In-class Use! No Publication or Distribution! 20  BIOL1152-02 Fall 2024 Categorizing the Living World Around Us Within the Domain Eukarya we have Four KINGDOMS - Protista unicellular, some multicellular algae - Animalia multicellular, no cell walls, heterotroph - Plantae multicellular, cell walls, autotroph - Fungi multicellular, cell walls, heterotroph 41 Categorizing the Living World Around Us Diverging System One Within the Kingdom Animalia we have 33-ish Different Phyla Each Phylum has Several Classes (total of 107-ish) Each Class has Several Orders Each Order has Several Families Each Family has Several Genera Many Each Genus has Several Species 42 Copyrighted Material for In-class Use! No Publication or Distribution! 21  BIOL1152-02 Fall 2024 The Phylogenetic Tree of Life 100000s Species The “Leaves” 10000s of Genera The “Twigs” 1000s of Families 100s of Orders The “Branches” 100s of Classes 33 Phyla 1 Kingdom The “Root” 43 Biological Systems are based on Hierarchical Organization Cladistic System, aka the “TREE OF LIFE” Branches / Twigs carry related Organisms with a Common Evolutionary History Image: Science magazine Traditional Tree of Life dates back Modern version of the tree of life to Linnaeus’ idea (1770s) (Woese & Fox 1977) 44 Copyrighted Material for In-class Use! No Publication or Distribution! 22  BIOL1152-02 Fall 2024 Roadmap to the Tree of Life The Categories: Kingdom, Phylum (Phyla), Classes, Orders, Families, Genera, Species Solanum tuberosum Solanum Solanaceae Solanales Magnoliopsida Magnoliophyta Plant Kingdom Phylum Class Order Family Genus Species Animal Panthera leo Chordata Panthera Mammalia Felidae Panthera tigris Carnivora Canidae Canis aureus Canis Canis lupus 45 “Tree of Life” Reflects Evolutionary Relationship of Species Phylogenetic Tree is based on Comparison (Comparative *)! - *Anatomy and Morphology - *Physiology - *Molecular Genetics We are looking for Homologies, i.e., Common Origin = Common Ancestor! Natural Selection Resulted In Different “Versions” Arising From Common Base! Diversity Evolution 46 Copyrighted Material for In-class Use! No Publication or Distribution! 23  BIOL1152-02 Fall 2024 Homology, Different Forms go back to Common Origin / Ancestor Embryonic Development provides Clues to Phylogenetic Relationships! “Ontogeny Repeats Phylogeny” 47 Analogy, “Form Follows Function” No Common Origin/Ancestor, but Similar Solutions to same Problem Similar Structures, Similar Performance, but Different Origin! Looking at Details Reveals Analogous Origin! 48 Copyrighted Material for In-class Use! No Publication or Distribution! 24  BIOL1152-02 Fall 2024 49 Like Homologies Analogies are The Result of Natural Selection! Evolution 50 Copyrighted Material for In-class Use! No Publication or Distribution! 25  BIOL1152-02 Fall 2024 Roadmap to the Tree of Life Kingdom Phylum Class Order Family Genus Species Animal Panthera leo Chordata Panthera Mammalia Felidae Panthera tigris Carnivora Canidae Canis aureus Canis Canis lupus 51 What is a Species? Easy Question, No Easy Answer! ~30 Different Valid Species Concepts are in existence, serving different purposes by covering different specific aspects. No current species concept fills all requirements. The “Classic” Biological Species Concept! “Species = Reproductive Community of Populations that are Reproductively Isolated by various mechanisms from other populations and that occupy a specific niche in nature (ecological niche = occupation rather than location) - Interbreeding? This Classic Concept lacks Evolutionary - Common descent? and Phylogenetic Aspects! - Ecologic entity? 52 Copyrighted Material for In-class Use! No Publication or Distribution! 26  BIOL1152-02 Fall 2024 Roadmap to the Tree of Life: Species Concepts Evolutionary Species Concept: “Species = Distinct Lineage of Ancestor / Descendant Populations that Maintains its Identity from Other Lineages and has its own evolutionary tendencies and historical fate” Problem: When do we see a new species? Evolutionary Species Concept: “Species = Most Inclusive Population of Individuals with the Potential for Phenotypic Cohesion through Intrinsic Cohesion Mechanisms” Means: Gene flow Within this Population, shared loss of alleles by genetic drift, shared genetic changes by natural selection. Species has common gene pool! 53 Roadmap to the Tree of Life: Species Concepts Phylogenetic Species Concept: “Species = Irreducible Grouping of Organisms diagnosable Distinct from other Groupings and within there is a Parental Pattern of Ancestry and Descent ” 54 Copyrighted Material for In-class Use! No Publication or Distribution! 27  BIOL1152-02 Fall 2024 Important: An Individual Belongs Only To One Species When are Individuals Different Enough To Belong To Different Species? 55 Bonobo Pan paniscus; our closest living relative (99% DNA match)! Different genus (Pan), same family (Hominidae)! 56 Copyrighted Material for In-class Use! No Publication or Distribution! 28  BIOL1152-02 Fall 2024 Evolution: Individuals are what they are! Some are “Fitter” than other Individuals Do Not Change, Individuals Do Not Evolve Fit Individuals Survive and Reproduce (Pass Alleles On) at Higher Rate, Less Fit Individuals Do Not Populations Evolve over Generations! Over Time a Population is shaped by Higher Reproductive Success of “Fitter” Individuals, Beneficial Alles Become More Common in the Population 57 What is an Allele? A Gene comes in different Variants, i.e. Alleles (e.g., Gene for ABO Blood Type) Individual Allele Combinations leads to Genetic Variation within a Population (e.g. different individual ABO Blood Types) Genetic Differences between Populations lead to Genetic Variation within a Species (e.g. more Blood Type O Individuals in NA Indigenous Population compared to other Ethnic Populations) 58 Copyrighted Material for In-class Use! No Publication or Distribution! 29  BIOL1152-02 Fall 2024 Human ABO Blood Type Three Different Versions (Alleles) of the ABO Gene Type A Allele, Type B Allele, Type O Allele Two Alleles/Individual, One Allele Each Inherited from Mother and Father Phenotype Genotype (Alleles in Genome) (What we see) (What we can pass on to next generation) Blood Type A AA, AA, AO, OA A shows as A Dominant over O Blood Type B BB, BB, BO, OB B shows as B Dominant over O Blood Type O OO, OO Recessive O shows when homozygous Blood Type AB AB, AB A and B are Co-Dominant 59 Selection Pressure Drives Evolution! “Recombination Mixes Cards, Selection Pressures Decide What Deck Wins” What Drives Evolution: Natural Selection: Works on Variants of a Trait that are Heritable (Genetic Variance!) One Variant Offers Benefits for Survival and Reproduction (Fitness!) Favorable Variant will Increase in Frequency in a Population over Time Artificial Selection: Works on Variants of a Trait that are Heritable (Genetic Variance!). Variant of Trait that Offers Benefits for Survival and Reproduction (Fitness!) will Increase in Frequency in a Population over Time (Generations!). What is the Difference? 60 Copyrighted Material for In-class Use! No Publication or Distribution! 30  BIOL1152-02 Fall 2024 Result of Natural Selection - Natural Selection favors Fittest Individuals (Traits) - Different Environments Require Different Trait Variants for Fitness 61 Some Results of Artificial Selection Would Have Little Chance Wikipedia.org to Survive and Reproduce Without Human Selector! 62 Copyrighted Material for In-class Use! No Publication or Distribution! 31  BIOL1152-02 Fall 2024 Natural Selection Evolution driven by Natural Selection (or artificial selection) requires: 1) Existing Variation in the Trait = different varieties 2) Different Traits must have Different Fitness Consequence, must affect reproductive success differently 3) Mode of Inheritance = a way that allows trait to be passed on into the next generation 4) Trait aims at limited Resource 63 Summary: Natural and Artificial Selection drive Evolution (difference is the “selecting agent”) Evolution works on Population over Generations, NOT on Individual Trait must be present in Different Variants (Alleles) that offer different benefits! => Variability of Trait Trait variant selected against must be transferable to next generation, i.e. genetically manifested, and offer selective advantage 64 Copyrighted Material for In-class Use! No Publication or Distribution! 32  BIOL1152-02 Fall 2024 Evolution of Behavior Natural Selection vs Artificial Selection Variation in a Trait Variety of Traits is rooted in Genetic Variation A Gene comes in different Variants, i.e. Alleles (e.g. Gene for Hair Color with black, brown blonde alleles) Usually more than one Gene is involved in Forming a Trait Individual Genetic Differences lead to Genetic Variation within Population (e.g. different shades of blonde, brown hair …….) Genetic Differences between Populations lead to Genetic Variation within a Species (e.g. more blonde-haired individuals in Northern Europe than in the Mediterranean) 65 Example for Trait Variance: Human ABO Blood Type Three Different Versions (Alleles) of the ABO Gene Type A Allele, Type B Allele, Type O Allele Two Alleles/Individuals One Allele each from Mother and Father Phenotype Genotype Type A AA, AA, AO, OA A shows as A dominant over O Type B BB, BB, BO, OB B shows as B dominant over O Type O OO, OO Recessive O shows when homozygous Type AB AB, AB A and B are Codominant 66 Copyrighted Material for In-class Use! No Publication or Distribution! 33  BIOL1152-02 Fall 2024 67 Variation in a Trait Genetic Variation in Population is generated by: - Random Genetic Recombination during Meiosis and Fertilization (and Crossing-Over) Benefit of Sexual Reproduction - Migration (Gene Flow) “Import” of Alleles from other Populations into Gene Pool of a Population - Gene Drift “Loss” of low frequency alleles from the Gene Pool of a Population - Random Mutation of Alleles “New” Allele in Gene Pool of Population least common mechanism 68 Copyrighted Material for In-class Use! No Publication or Distribution! 34  BIOL1152-02 Fall 2024 Gene Flow (Gene Migration): Population 1 @ Generation 1 + x Population 1 Population 2 Population 1 @ Generation 1 + x 69 Genetic Drift: Genetic Drift can alter allele frequencies in the gene pool of small populations! Founder Effect: Few individuals start a new, isolated population. Small gene pool to begin with and some alleles may not be represented from the very beginning. 70 Copyrighted Material for In-class Use! No Publication or Distribution! 35  BIOL1152-02 Fall 2024 Random Mutation of Alleles Original Mutant Parent Offspring 71 Life ?! What is Life? What makes Something Alive? What are the Basic Requirements of Life? 72 Copyrighted Material for In-class Use! No Publication or Distribution! 36  BIOL1152-02 Fall 2024 Life on Earth: A “Brief” Timeline 13 x 109 years = 13 billion years “BIG BANG” 13000000000 years 5 x 109 years = 5 billion years EARTH 5000000000 years 4 x 109 years = 4 billion years LIFE on Earth 4000000000 years 230 x 106 years = 230 million years Dinosaurs 230000000 years 200 x 103 years = 200 000 years Homo sapiens (we) 1 x 102 years = 100 years Lifespan of a human 73 Life on Earth: A “Brief” Timeline Billions of Years (1 Billion = 1000 Million) Millions of Years 0.2 74 Copyrighted Material for In-class Use! No Publication or Distribution! 37  BIOL1152-02 Fall 2024 Numbers in Science yotta [Y] 1 000 000 000 000 000 000 000 000 1024 zetta [Z] 1 000 000 000 000 000 000 000 1021 exa [E] 1 000 000 000 000 000 000 1018 peta [P 1 000 000 000 000 000 1015 tera [T] 1 000 000 000 000 1012 a billion (uncommon) giga [G] 1 000 000 000 109 a billion (common) mega [M] 1 000 000 106 a million kilo [k] 1 000 103 a thousand hecto [h] 100 102 deca [da] 10 101 1 100 deci [d] 0.1 10-1 a tenth centi [c] 0.01 10-2 a hundredth milli [m] 0.001 10-3 a thousandth micro [µ] 0.000 001 10-6 a millionth nano [n] 0.000 000 001 10-9 pico [p] 0.000 000 000 001 10-12 femto [f] 0.000 000 000 000 001 10-15 atto [a] 0.000 000 000 000 000 001 10-18 zepto [z] 0.000 000 000 000 000 000 001 10-21 yocto [y] 0.000 000 000 000 000 000 000 001 10-24 Dimensions commonly used in life sciences! 75 Dimension & Unit 1 km 1000 m 1 x 103 m 0.001 km 1m 1000 mm 1 x 100 m 0.001 m 1 mm 1000 µm 1 x 10-3 m 0.001 mm 1 µm 1000 nm 1 x 10-6 m 0.001 µm 1 nm 1000 pm 1 x 10-9 m Capital and Small Letters Matter, A LOT! M = Mega (106) / Molar (concentration) m = milli (10-3) / meter (distance) Numbers Without Units Often Make No Sense! 76 Copyrighted Material for In-class Use! No Publication or Distribution! 38  BIOL1152-02 Fall 2024 120 pm 1.4 million km Using Suitable Orders of Magnitude Makes Communication Easier and Less Prone to Misunderstanding 77 0.0001 µm 0.001 µm 0.010 µm 0.100 µm 1 µm 10 µm 100 µm 1000 µm 0.1 nm 1 nm 10 nm 100 nm 1000 nm 10000 nm 100000 nm 1000000 nm Usable Scale Size of Individual Cells Non sensical Scale Light Microscopy Electron Microscopy 78 Copyrighted Material for In-class Use! No Publication or Distribution! 39  BIOL1152-02 Fall 2024 What is Life, What Makes Something Alive? We Need A Definition! 79 Criteria to Consider When Defining Life! Cellular Organization All organisms consist of one or more cells, Cell is the smallest Unit of Life Criterium #1 Ordered Complexity complex interacting structures and processes No Energy Turnover Energy Utilization => Dead Organism Life and staying alive Requires Energy that needs to be acquired by organisms Homeostasis => Costs Energy Maintenance of stable internal conditions, conditions different from environment 80 Copyrighted Material for In-class Use! No Publication or Distribution! 40  BIOL1152-02 Fall 2024 More Criteria to Consider! Growth, Development, and Reproduction Hereditary molecules (DNA) passed on to offspring Sensitivity Ability to perceive and react to stimuli Evolutionary Adaptation Adaptability to biotic and a biotic conditions THERE IS NOT A SINGLE CRITERION TO DEFINE LIFE! Cellular Organization and Energy Turnover are Major Criteria 81 Copyrighted Material for In-class Use! No Publication or Distribution! 41