Cycles & systems..introduction (Teach)


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More for teachers who do not have much science background than for students. Discusses the ideas of cycles and systems and goes into some detail about some representative sample cycles.

This could be followed by the water cycle slide show:

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Cycles & systems..introduction (Teach)

  1. 1. • What do these words have to dowith science?Cycles and Systems•Cycles and Systems explore the constantprocesses that surround us. All of theEarth’s processes connect and worktogether. From the movement of rocks tothe changing forms of water, we find thatless than 100 elements and the Sunsenergy are the keys to all living things.Everything!By Moira Whitehouse PhD.Must be downloaded or saved in order to see the animations)
  2. 2. •In every discipline of science:biology, geology, astronomy, meteorology, physics and chemistry, we find thatwhatever functions are being performedthey are frequently performed as part ofsome cycle in some system. When onepart of a cycle fails or is removed, thecycle and the system fails.
  3. 3. •And here is a list of a few systems:Moon and Earth, Solarsystem, galaxies, ecosystems, food web, all bodysystems, (skeletal, digestive, immune, etc)•Here is a list of just a few cycles:electrical circuit, bicycle, gas engine, rockcycle, water cycle, carbon cycle, nitrogencycle, phosphorous cycle, cycle of sunspots, mooncycle, season cycle, Celoin cycle, Kreps cycle, foodcycle, cycle of constructive and destructive forces.
  4. 4. First, let’s look at cycles. What is a cycle?• In general: Any complete round or series ofoccurrences that repeats or is repeated.• In science: An interval of time during whicha characteristic, often regularly repeatedevent or sequence of events occurs:Sunspots increase anddecrease in intensity inan 11-year cycle• In science: A single complete execution of aperiodically repeated phenomenon:A year constitutes acycle of the seasons.• In science: A periodically repeatedsequence of events:The cycle ofbirth, growth, anddeath
  5. 5. Next, we’ll look at systems. What is a system?• In general: A combination of componentsthat act together to perform a function notpossible with any of the individual parts .the nervous system;the skeletal system• In biology: A group of physiologically oranatomically complementary organs or parts:• In astronomy : a number of heavenlybodies associated and acting togetheraccording to certain natural laws:the solar system;
  6. 6. •As we go through these few cycles andsystems, remember that this hardlytouches the surface...•but it does cover some of themajor ones that fifth grade studentsshould be familiar with.•In this order, we will look at:•Life cycle of a plant (this presentation)•The water cycle (a separate slide show)•The nitrogen and carbon cycles (a separateslide show)
  7. 7. Life cycle of a Plant
  8. 8. •The world of plants is large and complex.•We will study only a small part, the life cyclesof angiosperms (flowering plants).•The plant kingdom, however, includes manyother types of plants whose life cycleswill be very different the ones we will study.
  9. 9. •Here is a quick overview of the plant Kingdom:I. Bryophytes: Small withleaflike, stemlike, and rootlike structures.Reproduce by spores:mosses, liverworts, hornworts.II. Vascular Plants: Larger with true leaves,stems, and roots.B. Seed Plants:1. Gymnosperms: Usually have cones, noflowers, seeds not enclosed in fruit:pines, spruces, firs, hemlocks, cycads,A. Seedless: Reproduce by spores.Ferns, horsetails, club mosses.
  10. 10. B. Seed Plants:1. Gymnosperms: Usually have cones, noflowers, seeds not enclosed in fruit:pines, spruces, firs, hemlocks, cycads,ginkgo.2. Angiosperms: Have flowers, seedsenclosed in fruit.
  11. 11. Our aim in this section is to deepen ourunderstanding of the life cycle offlowering plants, the angiosperms.Most of us have a pretty good understandingof the basic stages of theflowering plant’s life cycle,but at the nitty-gritty level,things can becomecomplex.
  12. 12. As you may remember the life cycle of aflowering plant fits into the following stages:•Germination of the seed•Seedling•Mature plant•Development of the fruit•Flowering•Fertilization•Seed dispersal
  13. 13. As the following four processes are crucial toplant survival, we examine each one.•transpiration•fertilization•respiration•photosynthesis--the process ofmetabolizing (burning)glucose to yield energyfor growth, reproductionand other life processes.—the process bywhich the chlorophyllin plants captureslight energy which isthen used to convertcarbon dioxide andwater into a simplesugar called glucose.--the loss of watervapor through thestomata of leaves.--The joining of a maleand female cell.
  14. 14. photosynthesis—the process by which the chlorophyll inplants captures light energy which is thenused to convert carbon dioxide and waterinto a simple sugar called glucose.Let’s talk abouteach of these.
  15. 15. During photosynthesis, the leaves of a planttake in carbon dioxide from the air andreceive water from the soil. Using lightenergy, the plant changes these ingredientsinto a simple sugar called glucose.--cross section of a leaf, where all this magic work takes place. commons attribution image
  16. 16. The chemical equation for the chemical changeinvolved photosynthesis is:6CO2 + 6H20 = C6H12O6 + 6O2carbon dioxide water glucose oxygenLight energy provides the energy for this chemicalreaction.Light energy
  17. 17. Plant cells have cell structures called chloroplastswhich contain chlorophyll, a green substance thatabsorbs light energy. Chlorophyll is what givesplant leaves their green color. free for nonprofit use
  18. 18. Only plants can produce food thoughphotosynthesis. Animals cannot maketheir own food. However, both plantand animals cells respire— “burn”glucose in order to secure energy tocarry out their life processes. In plantsthat process is called “respiration”.
  19. 19. Respiration--the process of metabolizing (burning)glucose to yield energy forgrowth, reproduction and other lifeprocesses.
  20. 20. Remember, photosynthesis producesglucose and now we will see how thatglucose is used by the plant (throughrespiration) to get immediate energy forgrowth, reproduction and to absorbnutrients, etc.
  21. 21. Notice that the equation for respirationis the opposite of photosynthesis:C6H12O6 + 6O2 = 6CO2 + 6H20 + energyIn respiration, to grow and carry out itslife processes, a plant “burns” glucose.During this process, the glucose producedin photosynthesis combines with oxygen.This chemical change results in therelease of carbon dioxide, water vaporand energy.
  22. 22. 1. For storing food in seeds and roots. Beforewinter, some plants stores starch in theirroots so they can survive the winter andstart growing again quickly in the spring.Fats and oils are stored in seeds to use forgermination.A plant changes some of the glucoseit manufactures into substancessuch as starch, fats, and oils.It uses these substances for two things.
  23. 23. 2. To build plant tissues such asleaves, wood, flowers, fruit and roots.
  24. 24. for use by public noncommerical use by Natural Resources CanadaHere we can see the two processes—photosynthesis and respiration occurringin a leaf.
  25. 25. The undersurface of leaves have holescalled stomata. This is where carbondioxide and oxygen from the air enter theplant. It is also through these same holesthat carbon dioxide, oxygen and watervapor are released. images for nonprofit useImage from Enchanted Learning
  26. 26. Water vaporWater vaporCarbondioxideCarbondioxide andoxygenOxygenWaterOxygenPlants take upthe oxygenthey needthrough theirtheir leavesand throughtheir roots
  27. 27. Plants, animals and most microorganismsneed oxygen for respiration.This is why for plants and microorganisms toomuch water is deadly.And we just saw that some of that oxygencomes from the soil.Overly wet or saturated soils are detrimental toboth root growth and function, and to thedecomposition processes carried out bymicroorganisms in the soil.Water fills the spaces in the soil forcing theoxygen out.
  28. 28. Comparison of Photosynthesis & RespirationPhotosynthesis RespirationProduces sugars from energy Burns sugars for energyEnergy is stored Energy is releasedOccurs only in cells with Occurs in most cellschloroplastsOxygen is produced Oxygen is usedWater is used Water is producedCarbon dioxide is used Carbon dioxide producedRequires light Occurs in both dark andlight
  29. 29. transpiration--the loss of water vapor throughthe stomata of leaves
  30. 30. Transpiration is the process by which moistureis carried through plants from roots to smallpores on the underside of leaves, where itchanges to vapor and is released to theatmosphere.
  31. 31. Transpiration serves three purposes:1. Movement of minerals up from the root (in thexylem) and sugars (products of photosynthesis)throughout the plant (in the phloem). Water servesas both the solvent and the avenue of transport.2. Cooling of the plant.3. Turgor pressure. Water maintains pressurein cells much like air inflates a balloon,giving the non-woody plant parts form.Turgidity is important so the plant canremain stiff and upright and get to the light.It also is the force that pushes roots through soil.
  32. 32. Carbon dioxide is absorbed through thestomata (holes in the leaves) and watervapor and oxygen are given off.Image from NASA
  33. 33. FertilizationThe joining of a male and female cell.
  34. 34. To understanding fertilization in a floweringplant will need to look at the parts of aflower..
  35. 35. The pistil is made up of three parts: stigma, styleand ovary. The stigma is the sticky knob at the topof the pistil. The style is the stem that holds up thestigma and is attached to the ovary which containsthe female egg cells called ovules.The femalepart of theflower is thepistil which isusually in thecenter of theflower.
  36. 36. A stamen is made up two parts:The maleparts of theflower arecalled stamen.They usuallysurround thepistil.1. the anther at the top of the stamen whichcontains pollen (the male reproductive cells) and2. the filament which supports the anther.
  37. 37. Petals are also important parts of theflower, because they help attractpollinators such as bees, butterflies andbats.There are tiny green leaf-like parts calledsepals at the base of the flower. They helpto protect the developing bud.
  38. 38. During the process offertilization, pollen landson the stigma and a tubegrows down the style andenters the ovary.The male reproductivecells travel down the tubeand join with theovules, fertilizing them.Each fertilized ovuledevelops into a seed andthe ovary becomes thefruit.
  39. 39. The fruit is the ripened ovary of a plantcontaining the seeds. After fertilization, theovary swells and becomes the fruit. Fruits maybe fleshy fruits, seed pods, or shells. Manythings we all call vegetables are really fruitssuch as tomatoes, cucumbers and beans.Wikipedia commons
  40. 40. In order for fertilization to take place, theflower must be pollinated. Somethinghas to carry the pollen from the stamento the pistil usually of another flower.Birds, bats and insects such as bees arecommon pollinators., MA
  41. 41. Another way plants are pollinated is bythe wind. Grasses such aswheat, oats, barley and corn arepollinated by the wind.
  42. 42. Flowers such as those ofan oak tree, wheat, andcorn are pollinated bywind.Male tassels, female silks of a corn Stamens of a wheat flowerFlower of an oak tree
  43. 43. Bean seedPart of every seed is a tiny plant (embryo)with leaves, stems and root parts waitingfor the right condition to germinate. Theseed also contains a short-term supply ofstored food called the endosperm. It isused by the embryo for growth until theseedling can make its own food.
  44. 44. Part of every seed is a tiny plant (embryo)with leaves, stems and root parts waitingfor the right condition to germinate.The right conditions, of course will involvethere being some water there as well.Which brings us to our next subject, waterand theWater Cycle