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Biology the Science of Life

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  1. Biology the Science of Life Cells: 2.1.1. 2.1.2, 2.3.4,2.1.8-2.1.10 Classification: 5.5.1, 5.5.2, 5.5.5 Text: Ch. 1 (3-13), Ch. 23 (468-472)

  2. Syllabus statements • 2.1.1 – Outline the cell theory • 2.2.2 – Discuss the evidence for cell theory • 2.3.4 – Compare prokaryotic and eukaryotic cells • 2.1.8 – Explain that cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others • 2.1.9 – State that stem cells retain the capacity to divide and have the ability to differentiate along different pathways • 2.1.10 – Outline one therapeutic use of stem cells

  3. Syllabus statements • 5.5.1 –Outline the binomial system of nomenclature • 5.5.2 – List the seven levels in the hierarchy of taxa – kingdom, phylum, class, order, family, genus, species – using an example from two different kingdoms for each level • 5.5.5 – Apply and/or design a key for a group of up to eight organisms

  4. Study of Life • What is alive? • 6 shared characteristics • Order, Response, Growth and Development, Use of Energy, Homeostasis, Adaptation • How do we organize living things? • Hierarchy of Life

  5. Hierarchy of Life • Atoms, molecules, cellular organelles, cells, tissues, organs, organ systems, organism

  6. The 6 characteristics of life 1. Order All living things made of one or more cells Cells are the basic unit of life 2. Response Exhibit sensitivity Response to stimuli = pupil dilation, plants grow to light, blink 3. Growth Development & Reproduction DNA common hereditary molecule 4. Energy Utilization Uptake and Transformation Photosynthesis and Respiration (Green Plants & All organisms) 5. Homeostasis Maintaining constant internal conditions (Temp, Water balance, O2/CO2 ) Behaviorally or Biologically 6. Adaptation Change in response to Environmental Conditions Desert organsims minimize water loss

  7. Energy • Photosynthesis (Green Plants) sunlight +water + carbon dioxide  oxygen + sugars • Respiration (All living things) oxygen + sugars  ATP +water + carbon dioxide • ATP is molecular energy storage

  8. Cells are the basic unit of Life!! • Cells 0-100 millionths of a meter (10-100 micrometers mm) • Not observed until we had technology to do so • Microscopes invented in mid 17th century • First light microscopes then electron microscopes more recently

  9. Timeline of Cell Discovery • 1590 – Zachariah Jansen -Invented compound (2 lens) microscopes

  10. Timeline of Cell Discovery • 1665 – Robert Hooke -Examined cork -First to see dead cells, called cellulae (small rooms) for little compartments

  11. Timeline of Cell Discovery • 1650-1700 – Anton von Leewoenhoek -Dutch botanist used lens x200, x300 -First to examine living cells, pond water, sperm, blood -Called animalcules (little animals) in p.w. -single celled organisms

  12. Timeline of Cell Discovery • 1707-1778 Carolus Linnaeus -swedish physician and botanist -founder of taxonomy -developed classification system for all living organisms

  13. Timeline of Cell Discovery • 1838 – Matthias Schleiden -German botanist -cell theory -plant observations *all plants made of cells

  14. Timeline of Cell Discovery • 1839 – Theodor Schwann -German biologist -Cell Theory -All animals are made of cells

  15. History continued • Purkinje: fibers that transmit stimulus to myocardial cells of ventricles of heart bear his name; coined term “protoplasm” for the living content of cells. 1855: Rudolf Virchow: studied pathogenic organisms and showed that “omnis cellula e cellula” – all cells arise from preexisting cells (by cell division).

  16. Timeline of Cell Discovery • 1940’s – Advent of the Electron Microscope TEM – transmission of electrons through specimen SEM – scanning of surface with electron

  17. Electron Micrographs

  18. Cell Theory • Three principles based on different studies • All organisms made of cells • Cells are the basic unit of life • Cells come from other preexisting cells • BUT… All cells aren’t created equal

  19. Prokaryotes (All are Prokaryotae) Very small (1-10um) No nucleus (nucleoid – DNA in central area) No membrane bound organelles Have cell walls Eukaryotes (all other kingdoms) Size 10-100 um DNA in chromosomes in nucleus Many M.B.O. Plants & some fungi have cell walls The two major types of cells

  20. To have different cells do different things you need differentiation • So cells develop along different pathways or differentiate • This means different cells express different genes • Remember that every cell in an organism has all the same DNA, only some cells express different genes within that genome • Once the developmental pathway of a cell is started then it is usually fixed

  21. So which cells can differentiate? • Stem cells – can self renew and differentiate • Human embryos are almost all stem cells • Some still found in different human tissues like skin, liver bone marrow • Those only used for limited repair

  22. Therapeutic use of stem cells • Area of rapid development – many uses exist • Cord blood from umbilical cord contains hematopoietic stem cells – can become any blood cell type • Test the blood and remaining fluid • Used to treat some leukemias – chemo to kill the cells that over produce white blood cells then introduce cord blood to blood stream of patient • Stem cells establish themselves in the marrow and replace defective cells

  23. Possible fates of cord blood stem cells

  24. Classifying all this life

  25. Diversity of Cells Diversity of Life • Currently 1.5x106 identified species • Study and grouping of this diversity is the science of taxonomy • Taxonomic hierarchy – KPCOFGS • Many systems – Ours 5 kingdoms -know examples of each

  26. 5 kingdom system: Prokaryotae • Monera (bacteria) • Hetero & Autotrophs • Archaebacteria -primitive, extremophiles (halo-, thermo-), don’t need O2 • Eubacteria -most of the bacteria -some parasites but all modes of nutrition 40,000x magnification

  27. 5 kingdom system: Protoctista • Protists -eukaryotes most unicellular -hetero & autotrophs -algae, amoeba, ciliates, diatoms

  28. 5 kingdom system: Fungi • Eukaryotes – most multicellular • Yeast, mushrooms, molds • Heterotrohpic – acquire food by absorbtion • If cell wall is present, made of chitin

  29. 5 kingdom system: Plantae • Multicellular, Autotrophic (Photosynthesis), Eukaryotes • Cells have a cell wall made of cellulose • Mosses, ferns, conifers, flowering plants

  30. 5 kingdom system: Animalia • Multicellular, Heterotrophic, Eukaryotes • Lack cell wall

  31. From Largest grouping to Smallest • Species – A population of organisms who have the potential to interbreed and produce fertile, viable offspring • Largest grouping of a population which can exchange genetic material but genetically isolated from other groups

  32. Classifying Organisms • Systematics – a classification process for studying biodiversity • Taxonomy – branch of biology concerned with naming and classifying organisms • Group species into larger categories from genus up to kingdom

  33. The Importance of Classification • Common names useless – panther, puma, mountian lion, cougar = Felis concolor • Shows evolutionary relationships – bears, raccoons sloths (p 47) • Enables predictions of characteristics shared by members of group – e.g.new primate discovered expect diagnostic char.

  34. The Importance of Classification II • ID of organisms by organizing ecological, anatomical, physiological, molecular (DNA & protein specifically) data 1. Proteins: Cytochrome C; has 104 Amino acids found in mitochondria 2. Consider differences in amino acids – human vs chimps = 0, human vs. dogs = 13, vs. snakes = 20, vs tuna = 33

  35. Binomial Nomenclature System • Created by C. Linneaus • Each species has 2 part Latin name • Genus species (computer) • Genus species (handwritten) • E.g. Homo sapiens = humans Felissylvestris = house cat Ranunculus acris = buttercup

  36. Remember: KPCOFGS(memorize the following examples)

  37. Remember: KPCOFGS(memorize the following examples)

  38. Review Points • 6 characteristics of Life • Levels of the hierarchy of Life • 3 principles of Cell theory • Difference between prokaryotes and eukaryotes • 5 kingdoms and their characteristics • Kingdom, Phylum, Class, Order, Family, Genus, species