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...All are welcome...

Lecture 2: What is life?. ...All are welcome. Now playing: Soft Cell “Tainted Love”. Lecture 2: Goals. 1. Define:. 2. Understand:. 3. Relate topics to:. Assignment:. Read: Chapter 2 and 3 for next Tuesday Read:Chapter 5, 6, and 7 for next Thursday. 2. Websites:

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  1. Lecture 2: What is life? ...All are welcome... Now playing: Soft Cell “Tainted Love”

  2. Lecture 2: Goals 1. Define: 2. Understand: 3. Relate topics to: Assignment: • Read: Chapter 2 and 3 for next Tuesday • Read:Chapter 5, 6, and 7 for next Thursday 2. Websites: http://www.mad-cow.org/ http://organicconsumers.org/meatlink.html http://www.mhhe.com/biosci/genbio/maderinquiry /crit6.html http://www.mhhe.com/biosci/genbio/maderinquiry/crit3.html

  3. It’s Difficult to Understand Life and Death • No first hand information • Can’t remember death • Can’t remember when life started

  4. Characteristics of Death • Absence of life • Total and permanent cessation of all vital (living) function • Absence of the characteristics of life

  5. Properties of Life • Dynamic = changing • Adaptability • Contain Information (DNA) • Ordered Structure • Uniformity of class

  6. Definition of Life • An organismic state characterized by the capacity for metabolism, growth, reaction to stimuli, and reproduction. • A principle or force that underlies the distinctive quality of animate beings. • The quality that distinguishes a vital and functional organism from inanimate objects.

  7. LIFE Key Terms in “Life” Definition • Metabolism • Acquires and expends “energy” • Growth • Makes what it needs • Reaction • Senses Environment • Reproduction • A population of one and only one is going to run into trouble sooner than later

  8. Life’s Characteristics Irritability An immediate response to stimulus = nervous system Adaptation An inherited characteristic that enables an organism to survive Reproduction Passing on the biochemical instructions (genes) to the next generation

  9. Components of Life • Elements (atoms) • Molecules • Macromolecules • Information carriers • Enzymes, proteins • Functional capacity • Membranes and walls • Boundaries, and containers

  10. Life’s Components Atoms Amino Acids Macromolecules Organelles Cells Tissues Organs Organ Systems Symbiotic organisms Individuals Populations Munn Field Riot 1998

  11. Life Quantitatively • Complexity • High • Low

  12. How Biologists Measure Size: Metrics Assignment: Learn the metric measuring system and life sizes

  13. What is the simplest form of life? • Phytoplasma and Mycoplasma = simplest cell, lack a cell wall, DNA for 200 functions (walking pneumonia, STD’s) Pneumonia mycoplasma • Virus = RNA or DNA wrapped in protein coat (HIV, poliomyellitis) HIV

  14. How Simple Can it Be? • Viroid = Tightly wound DNA or RNA (coconut cadang cadang, bunchy top) Cadang cadang • Prions = 1/100 to 1/1000 the size of a virus, composed of proteins (Scapies, Multiple Sclerosis, Lou Gehrig’s disease) scapies

  15. BSE Mad Cow Disease BSE:Bovine Spongiform Encephalopathy Prions in action Transmission via contaminated sheep proteins fed to cattle in Great Britain

  16. Organizing Life Systematics Taxonomy Cladistics Phylogenics Natura non facit saltum (Nature does not make leaps). The Tree of Life from Darwin's notebook of 1837

  17. Classification • Kingdom • Phylum • Class • Order • Family • Genus • Species

  18. Classification The Kingdoms • Animalia- multicelluar, consumers • Plantae- multicellular, consumers • Fungi- mostly decomposers • Protista- One-celled, producers and consumers • Eubacteria- Normal, true bacteria, consumers… • Archaebacteria- Extreme bacteria, consumers…

  19. Classification • Methods of Classification • Based on some relevant distinguishing characteristic • It should be meaningful • It should not be arbitrary • Basis of Classifications • Morphological characteristics • Types of structures, Size, Diet, Reproduction • Molecular characteristics • Mitochondrial DNA • Nuclear DNA

  20. So Who’s Related DNA sequences provide a direct record of the genealogy of extant species. surprising changes have recently been proposed for The tree of mammalian orders. These range from grouping whales with hippos, to placing African golden moles closer to elephants than to their fellow insectivores. Molecules remodel the mammalian treeWilfried W. de JongTrends in Ecology & Evolution 1998, 13:270-275

  21. Functions of Life • Metabolism • Growth • Reaction • Reproduction

  22. Metabolism • Animal model • Plant model

  23. Animal Metabolism Change Self Perpetuation Reproduction Metabolism Synthesis Offspring Energy Energy Detritus Cycles Raw Materials H2O Cycle Growth and Development Steady State Respiration Nutrient Cycles

  24. Plant Metabolism Sunlight Carbohydrate Energy rich O2 Chloroplast Mitochondrion Energy poor CO2 + H2O Fusion ATP Biosynthesis Active transport Movement Bioluminescence Electricity 4H 1 He + e E = MC2 Photosynthesis Cellular respiration

  25. Growth • Using the stored energy • Incorporating acquired materials Catabolic processes- breaking down Anabolic processes- building up These terms refer to breaking and making chemical bonds

  26. Reaction • Sensing environment • Receptors • Metabolic changes • Reacting to changing environment • Bacteria • Plants • Animals • Reacting to internal environment • Homeostasis

  27. Reproduction • Sexual Reproduction • Cell Process: Meiosis • Mixing Genes • Replication, Division • Cell Process: Mitosis • High fidelity copies • Adaptation and Selection

  28. Where does life come from? • Neo-Darwinian • Macro Evolutionary Process • Cosmic Inoculation • Panspermia • Divine Creation

  29. Origin of LifeWhere did it come from? Life is a property of matter and energy • Abiogenesis Origin (Neo-Darwinian) Macro Evolutionary Process Chance, Necessity, and Self Organization Chemical processes generated life precursors Precursors assembled into proto cells • Extraterrestrial deposition (Panspermia) Organisms came from somewhere else Chemistry came from somewhere else

  30. The Big Bang • 12-15 billion years ago all matter was compressed into a space the size of our sun • Sudden instantaneous distribution of matter and energy throughout the known universe • Planet Formation • About 4.6 and 4.5 billion years ago • Minerals and ice orbiting the sun started clumping together • Heavy metals moved to Earth’s interior, lighter ones floated to surface • Produced outer crust and inner mantle

  31. Earth Is “Just Right” for Life • Smaller in diameter, gravity would not be great enough to hold onto atmosphere • Closer to sun, water would have evaporated • Farther from sun, water would have been locked up as ice

  32. Initial ConditionsFirst Atmosphere Hydrogen gas Nitrogen Carbon monoxide Carbon dioxide No gaseous oxygen

  33. Stanley Miller’s Experiment • Mixed methane, hydrogen, ammonia, and water • Simulated lightning • Amino acids and other small molecules formed gases boiling water water containing organic compounds

  34. RNA World • DNA is genetic material now • DNA-to-RNA-to-protein system is complicated • RNA may have been first genetic material • RNA can assemble spontaneously • How switch from RNA to DNA might have occurred is not known

  35. living cells enzymes and other proteins DNA RNA formation of protein–RNA systems, evolution of DNA formation of lipid spheres spontaneous formation of lipids, carbohydrates, amino acids, proteins, nucleotides under abiotic conditions Possible Sequence membrane-bound proto-cells self-replicating system enclosed in a selectively permeable, protective lipid sphere

  36. Presuppositions • Do Presuppositions Matter? • Naturalism and Materialism • Life is a property of matter and energy • Chance, Necessity, and Self Organization • Of course it works, we’re here aren’t we?

  37. Normal Science Crisis Revolution Prescience Origin of LifeWhere did it come from? New ideas, new questions Matter, Energy, and Information Where does the information come from?

  38. Identifying Life Its life Jim, but not as we know it

  39. Identifying LifeDoes Life Exist Elsewhere in the Universe? • Are terrestrial biochemistry and molecular biology the only such phenomena that can support life? • With only one example, we don’t know which properties of life are general and necessary, and which are the result of specific circumstances or historical accident. http://astrobiology.arc.nasa.gov/roadmap/goals/index.html

  40. Lecture 2: What is life Summary Definitions Properties Characteristics Organization Life and Energy Measuring Life Forms of Simple Life Origin of Life Now playing: Soft Cell “Tainted Love”

  41. END Life is what happens when you’re busy making other plans. --John Lennon (1940-1980) British singer/songwriter

  42. Lecture 2: Outline • What is life • Characteristics- Definition- • Properties- Dynamic changing • Components- building blocks • Minimal life- simplest life forms • Organizing Life • Taxonomy • Functions of Life • Metabolism • Plant • Animal • Carbon, nitrogen and water cycling • Origin of Life • Where did it come from • Current Models • Introduction to Biological Chemistry

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