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What is Life

Bio Lecture ppt
The Process of Science, Chapter 1

CC BY, Leslie Orzetti-Gollhofer

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What is Life

  1. 1. What is Life? Biology, Science, and How we Study Things.
  2. 2. What is Science
  3. 3. What is Life? • Biology is the scientific study of life • Define life by listing basic components – Cell is basic unit of life – Every organism is one or more cells – DNA used to produce proteins Figure 1.1 Informational Molecule of Life.
  4. 4. Properties of Life 1. Organized 2. Uses energy 3. Maintains internal environment 4. Reproduces 5. Responds to the Environment 6. Grows, and develops 7. Evolves
  5. 5. Properties of Life 1) Order 2) Reproduction 3) Growth & Development 4) Energy Processing 5) Response to the Environment 6) Regulation 7) Evolutionary Adaptation
  6. 6. Properties of Life: Order • Life has order and energy is required to maintain this order 1) Order
  7. 7. Properties of Life: Reproduction • Life Reproduces Itself, Grows, and Develops – Asexual reproduction • All offspring identical – Sexual reproduction • Offspring have new combination of traits – Growth and development
  8. 8. Figure 1.5 Asexual and Sexual Reproduction. Properties of Life: Reproduction
  9. 9. Properties of Life: Growth and Development • Grow and Develop – cell division and specialization until maturity
  10. 10. Properties of Life: Energy • Every living thing needs energy to live – Metabolism – sum of the chemical reactions in an organisms that produce and use energy • Living things classified by how get energy – Producers – Autotrophs, make own food from nutrients and non-living sources (sun) – Consumer – Heterotroph, get energy by consuming other organisms (dead or alive) – Decomposer – Heterotroph, get energy from dead organisms or wastes • All types of organisms live together in ecosystem and make a food web
  11. 11. Properties of Life: Energy Producer Consumer Decomposer
  12. 12. Simple Food Web Producers extract energy and nutrients from the nonliving environment Consumers obtain energy and nutrients by eating other organisms. Decomposers are consumers that obtain nutrients from dead organisms and organic wastes.
  13. 13. Properties of Life: Energy
  14. 14. Properties of Life: Respond to Environment • Life can sense and react to stimuli • To do this, cells have to be in constant environment (relatively!)
  15. 15. Properties of Life: Regulation/Homeostasis • Homeostasis – Process by which cell or organisms maintains a state of internal constancy or EQUILIBRIUM • Ex. Your internal temperature is 37⁰C or 98.6⁰F
  16. 16. Properties of Life/Adaptation • How life changes over time to become best suited to its environment – Adaptation – Inherited trait that make organisms better suited to environment • Better survival • More successful reproduction – Natural Selection – Through adaptation, a set of traits that make one organism more successful than another • Enhanced reproductive success leading to more individuals
  17. 17. Properties of Life/Adaptation
  18. 18. Properties of Life: Natural Selection in Bacteria
  19. 19. Life is Organized • Atoms • Molecules • Organelles • Cells • Tissues • Organs • Organ Systems • Organisms • Population • Community • Ecosystem • Biosphere • Emergent Properties – Interacting properties that give an organisms a complex function – Change the structure, change the function – Interrupt the function too much, structure breaks down
  20. 20. ATOM: The smallest chemical unit of a type of pure substance (element). Example: Lithium atom MOLECULE: A group of joined atoms. Example: DNA ORGANELLE: A membrane-bounded structure that has a specific function within a cell. Example: Chloroplast CELL: The fundamental unit of life. Example: Leaf cell TISSUE: A collection of specialized cells that function in a coordinated fashion. Example: Epidermis of leaf ORGAN: A structure consisting of tissues organized to interact and carry out specific functions. Example: Leaf COMMUNITY: All populations that occupy the same region. Example: All populations in a savanna ECOSYSTEM: The living and nonliving components of an area. Example: The savanna BIOSPHERE: The global ecosystem; the parts of the planet and its atmosphere where life is possible. ORGANISM: A single living individual. Example: One tree ORGAN SYSTEM: Organs connected physically or chemically that function together. Example: Aboveground part of a plant POPULATION: A group of the same species of organism living in the same place and time. Example: Multiple acacia trees
  21. 21. Organization of Life
  22. 22. Tree of Life - Bacteria • Cells lack nuclei (prokaryotic) • Unicellular DOMAIN BACTERIA
  23. 23. Tree of Life ArchaeaCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Cells lack nuclei (prokaryotic) • Unicellular DOMAIN ARCHAEA
  24. 24. Tree of Life Eukarya • Cells contain nuclei (eukaryotic) • Unicellular or multicellular DOMAIN EUKARYA Kingdom Animalia • Multicellular • Heterotrophs (by ingestion) LM 200 µm Kingdom Fungi Kingdom Plantae • Most are multicellular • Heterotrophs (by external digestion) • Multicellular • Autotrophs Protista (multiple kingdoms) • Unicellular or multicellular • Autotrophs or heterotrophs
  25. 25. Scientific Method • Sir Frances Bacon: the 1st to document the scientific method
  26. 26. Scientific Method
  27. 27. Experimental Design • Used to test hypotheses – Can be controlled (in a lab) or in the natural environment • What you need to consider – Sample size – How many individuals or observations do you have to make – Variables – What can change in your experiment • Independent Variable – The thing you change • Dependent Variable – The response • Standardized Variable – Constant – Control – Provides basis for comparison – Statistical Analysis – Math using your data to prove or or disprove your hypotheses
  28. 28. Sample Experiment Observations – Fish community looks different when you change the shoreline Hypothesis – A change in shoreline structure will change the fish community Data Collection – Seine sampling to collect fish at sites Sample Size – Measure 10 fish per species, total count, total biomass of all fish in each haul Control – Control Sites – those with no change in shoreline Impact Sites – those with shoreline change Data Analysis – Metrics (diversity, species richness, biomass), Statistical analysis Theory – Based on data, the fish community is different at control sites than impact sites
  29. 29. Case Study on the Scientific Method Question: Why do baby coots have ornamental plumage during the first three weeks of life? Hypothesis: Bright ornamental plumage makes the chicks more attractive to the parents and increases survival Prediction: If the hypothesis is supported, then removing the ornamental plumage will decrease survival (and body weight) of the chicks.
  30. 30. Case Study on the Scientific Method Experimental Design: removed colorful plumage None trimmed (control) All trimmed (control) ½ trimmed (experimental)
  31. 31. Case Study on the Scientific Method Data: Measured weight and survival of the chicks CONCLUSIONS?
  32. 32. Basic vs. Applied Science • Basic: “pure science,” gain knowledge • Applied: “technology,” solve real-world problems