When the material turns cloudy, take another pittendint Add carefully observe a drop of the liquid under the microscope. Look for coacervates. If you have added the acid too rapidly. coacervates after several attempts, repeat the procedure from the beginning, for you may When successful go to the next astivity amoeba, slides and compare your coacetates with an imobe. After you have done this. come back to this point and finish this activity 4) Add a drop or two of Methylene blue dye to one side of your cover slip. On the other side of Observe how the coacervates react to this dye. the cover slip, place a piece of tissue paper to draw the Methylene blue under the cover siip. 5) When you have finished your observation of the coacervates, add more acid to the test tube Continue until the solution becomes clear again. When the liquid becomes clear, examine a drop under the microscope and measure the new pH. Table 1. Data on Formation of Coacervates. pH Clear or Coacervates Notes and sketches cloudy present? Y/N Make a live mount of Amoeba from the culture bottle in lab. Find an Amoeba. Compare coacervate structure to that of this simple, single-celled organism. Make a sketch of each one, and list the properties of living things found (or lacking) in each. CHARACTERISTICS OF COACERVATES AND AMOEBA Coacervate Characteristics Amoeba Characteristics 5 gy21 Rev. Oct 2920 Questions on Chemical Evolution: Creating Coacervates. How do those materials that you used to make concervates compare with those that might have been present in the ancient occan? 2. In what pH range did the coacervates form? Did the pll change as expected as a result of adding more acid to the solution between coacervate formation and clearing? 3. How did the methylene blue enter the cracervates? Is this the same way it would have entered a living protist, or other cell? 4. Where would the first microspheres or coacervates have found energy? 5. Are coacervates alive? Is Amoeba alive? What is the difference? III. Domains Bacteria & Archaea. These domains contain prokaryotic unicellular or colonial organisms. Remember that a prokaryotic cell is a small, simple cell without a nucleus. While the coacervates you created Biology 21 Rev. Oct 2020 were not alive, the cyanobacteria that you see in this lab are very much alive, even if they don’t around much Bacteria are the smallest simplest type of life. Not surprisingly, they were also the first wype of life to appear in the fossil record. Most people are familiar with the pathogenic or disease causing, bacteria. However, the majority of bacteria are beneficial to us. They do not cause disease, but instead live on their own in nature. They are critical parts of the great biogeochemical cycles that keep our ecosystems healthy. Many bacteria are great decomposers recycling chemicals. The photosynthetic cyanobacteria not only produce food that is the base of many food chains, but they also produce oxygen, About 50% of the oxygen that we breathe is produced by cyanobacteria A bacterium is a single cell. This cell may have a rod shape, or a sphere shape or a spiral shape. Some bacteria have flagella for movement. Although bacteria occasionally exchange some genetic material in a primitive form of sex, they typically reproduce by binary fisietely when one bacterium splits into two bacteria. A single-celled organism is completely independent, and performs all of the functions of life itself In a colony, many fairly independent cells are joined together. Activity: The Bacteria. 1. Examine the living and preserved specimens and illustrations of bacteria. Use these to determine the characteristics of each species. Fill in the data in Table 2. Table 2. Data on Characteristics of Bacteria and Live Cyanobacteria. SPECIES DESCRIPTION OF CELLS Mixed Bacteria Prepared slide Anabaena Live cyanobacteria Oscillatoria Live cyanobacteria Questions on the Kingdom Bacteria and Kingdom Archaca. 1. What kind of cell do the Bacteria and Archaea have? 7 Biology 21 Rev. Oct 20 BA . What are the three basic shapes of bacteria? 3. Which of the examples you looked at are single cells? Which are colonies? 4. Why are cyanobacteria so important in the evolution of life on earth? (Hint: review your notes on the video.) 5. In what type of environment could you find Archaea today? IV. “Kingdom Protista”: The First Eukaryotes. This group contains eukaryotic unicellular or colonial organisms. This is the second cell type to appear in the fossil record. Remember that a eukaryotic cell has its DNA enclosed in a nucleus, and has many organelles. Biologists hypothesize that the eukaryotic cell evolved as a symbiosis of two or more prokaryotic cells. As you view some living protists, try and see how complex a single cell can be. Examine the models of Amoeba and Paramecitem to get an even better idea of their complex structure. Many species of protist are alive today. They can be classified according to structures concerned with locomotion (how they move) or with ingestion (how they get their nutrition). Some protists float, while other swim with cilia or flagella. Some just ooze from place to place. Some protists absorb decaying matter. Others are photosynthetic, these are green with chlorophyll. Some protists eat other protists and bacteria, and a few are pathogenic. Incredible numbers of protists can be found living in one drop of pond water. Many protists reproduce by simple mitosis. However, protists have discovered sex, and the advantages of genetic recombination Biologists know that once protists evolved, they developed into thousands of different species. Protists are so diverse that newer classification schemes do not even put them all into a single “Kingdom” group any longer, instead grouping some with animals and some with plants on the basis of their DNA sequences. Some of these protists (the slime molds and water molds) are very fungus-like in some of their characteristics. Biologists believe that fungus-like protists evolved into the first true fungus, and later the whole Kingdom of Fungi. Likewise, plant-like protists (green algae) would have evolved into the Plant Kingdom, and the animal-like protists (the protozoans), would have evolved into the Animal Kingdom. Activities on Kingdom Protista: The Protists. 1. Examine the preserved specimens, illustrations, and models of protists. Determine the characteristics of each major protist group, and fill in the data in Table 3. 8 Biology 21 Rev. Oct 2020 TOSHIBA ROTIST GROUP Data on Characteristics of Major Types of Protists. NAMES, DISCRIPTION Examples show Description Seaweeds Slime Molds and Examples shown: Wafer Molds Description: Protozoans Examples shown Description: 2. Examine the living protists under the microscope. Fill in the data in Table 4 Table 4. Data on Characteristics of Specifie Protozoans. SPECIES DESCRIPTION OR DRAWING Euglena Live protist Paramecium Live protist Amoeba Live protist Volves Live protist Diatom Shells Prepared slide Questions on Kingdom Protista: The Protists. 1. What kind of cell do the protists have? In the models of Amoeba and Paramecium, what organelles are shown? Is there a nucleus shown? Hogy 21 Rev. Oct 2020 TOSHIBA Na two or three angus-like protists such as might have evolved into wetung What characteristics make these proti fungu like? 3. Name tweet three plant-like protists, such as might have evolved into true planta. What characteristics make these protists plant-like? 4 Name two or three animal-take protists, such as might have evolved into me animals What characteristics make these protists animalik? V. Multicellular Life Arises: The Burgess Shale Paleontologists search through the fossil wonderland of the Burgess Shale, a fossilsite in Canada where new species can still be uncovered every year Trained reconstruction artists consult with paleontologists to make these fossils come alive” again in drawings, models, and computer animations that reveal the strange creatures of the past. Activities: The Burgess Shale. 1. Examine the illustrations and models of Burgess Shale life and the preserved specimen of Amphixus. Sketch and/or describe Piknia and Amphix CHARACTERISTICS OF PIRATA AND AMPHIOXUS Draw or Describe- Pikala Characteristics Amphiaxus Characteristics Questions on Multicellular Life Arises: The Burgess Shale. 1. List the five Burgess Shale creatures which are shown as models. Which of these may be our carliest known animal ancestor? What features does it have that make us think this? 10 Biology 21 Rev. Oct 2020 No one knows exactly how or when living cells first se, but biologists encally accepta required specific physical conditions on our planet such as abundant liquid water and dissolved process called chemical evolution. The main points of this process are summad) life minerals 2) organic building blocks ( mm) came from simple inorganic molecules such as thethane (CH4), armona (NH3), and water vapor (H2O); 3) organie monomes combined to form polymers macromolecules), and 4) some form of molecular self-replication must have arisen (RNA or DNA This last step is perhaps the most difficult to maine, but RNA has recently been shown to have some remarkable catalytic activities The next step in chemical evolution is for the polymers to become grouped together in clusters and form membrane-bound compartments That is the first large molecules in the sticcessful than others. Eventually the more successful microspheres crowded out the less this cares may have competed with each other for necesary organic molecules (food) Dating complexity until they came to resemble a heterotrophic, prekaryotic cell. In 1924, a Russian biochemist named Alexander 1. Oparin considered the origination of life argregation of chemicals that superficially resembles a simple cell. Under certain conditions. coacervates have some of the properties of living things, droplets like them might have been an important step in the origin of life. We will make coacervates in lab (or view images online) Activities on Chemical Evolution: Creating Coacervates Create coacervates and examine their formation and structure. Work in small groups of about 4 people. Each group should get out at least one microscope. Procedure for Creation of Coacervales: 1) Obtain the following equipment and chemicals from the side table. Test tube with parafilm and a test tube stand Graduated cylinder 1% gelatin solution (protein) in the incubator) Gum Arabic solution (carbohydrate) (in the incubator) Hydrochloric acid, O.I M Small strip of pH paper and a color reference card Pipettes or droppers Microscope slides and cover slips Methylene blue (a dye) 2) Mix together 5 ml of the gelatin solution and 3 ml of the Gum Arabic solution in a test tube. Measure the pH of this mixture. Note whether the mixture is clear or cloudy. Place a drop of the liquid on a slide, add a cover slip, and observe it under the low power of the microscope. Look for coacervates. Have they formed yet? Record all of your observations in Table I as you proceed. 3) Carefully continue to add acid, 5 drops at a time, to the test tube. After each addition of 5 drops of acid, cover the tube and shake to mix the solution well. Wait a few seconds to see if Biology 21 Rev. Oct 2020 TOSH added the acid too rapidly. the solution becomes cloudy. When the material tms cloudy, take another pH reading. Add carefully observe a drop of the liquid under the microscope. Look for coacervates If you a few more drops of acid and mix. The material should be even clouder. At this point, cannot see them, try dumming the light and use a higher power If you still do not observe coacervates after several attempts, repeat the procedure from the beginning for you may When you succesful to the next activity Listides and compare your coacerates with an och Asthave done them back to this point and finish 4) Add a drop or two of Methylene blue dye to one side of your cover slip. On the other side of the cover slip. place a piece of tissue paper to draw the Methylene blue under the cover slip Observe how the coacervates react to this dye. S) When you have finished your observation of the coacervates, add more cid to the test tube, a drop at a time. Mix after adding each drop and measure the pH after every third drop. Continue until the solution becomes clear in. When the liquid becomes clear, exame a this activity drop under the microscope and measure the new pH. Table 1. Data on Formation of Coacervates. pH Clear or Coacervates cloudy2 Notes and sketches present? YN Make a live mount of Amoeba from the culture bottle in lab. Find an Amoeba. Compare coacervate structure to that of this simple, single-celled organism. Make a sketch of each one, and list the properties of living things found (or lacking) in each. CHARACTERISTICS OF COACERVATES AND AMOEBA Coacervate Characteristics Amoeba Characteristics 5 Biology 21 Rev. Oct 20
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