Algae Millersville University Herbarium

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Algae or singular alga is historically a term applied to an unnatural assemblage of photosynthetic. organisms that are usually morphologically simpler than members of the plant kingdom the plant. kingdom including bryotphytes pteridophytes and seed plants Some algae are unicellular but others. are larger and multicellular organisms that are called seaweeds Within the algae you can see the. major trend in the evolutionary development of multicellularity reflected in the diversity of organismal. forms i e unicellular filamentous exhibiting 1D multicellular growth planar thalloid exhibiting. 2D multicellular growth 3D forms that begin to resemble plants in their complexity This is important. b c it is this evolutionary trend that gave rise to the Kingdom Plantae from amongst the green algae in. particular, Algae have been divided into groups based mainly on distinctive plastid accessory pigments. Because of these pigments many groups of algae have been known by their color hence red green. brown etc Modern classifications delimit them with many other characters such as cell wall. components reproductive structures and distinctive food storage molecules. Algae are the dominant producers in aquatic environments so they are very important. ecologically The materials available in lab today represent the major algal divisions along with the. cyanobacteria,Some Useful Terms for Algae in this lab. Bladder see pneumatocyst, Blade the flattened analog of a leaf in many seaweeds. Coenocytic an organism whose cell s contain multiple nuclei e g the alga Vaucheria exists as a. long sometimes branched filament that is just one or few giant cells. Colonial an organism actually made up of multiple organisms In algae these individual. organisms are typically unicellular and they stick to one another by a special gelatinous matrix they. Eyespot a patch of pigment on a membrane inside a cell that can detect light These are typically. red and found only in motile algae since the cell once it detects light can them swim towards it or. away from it if it is too much, Filamentous an organism that is long and thin sometimes branching and typically made up of a. string of cells, Holdfast the branching structure at the base of many seaweeds that hold them to a substate.
Motile to have directed mobility Cells able to propel themselves by some means are said to be. motile Usually this is achieved by way of a flagellum or two e g Chlamydomonas However. the filamentous cyanobacterium Oscillatoria can move by way of the entire filament and mass of. filaments oscillating or twirling and desmids such as Closterium can move in a somersaulting. motion by secreting jets of mucilage through special pores in the cell wall alternatingly from. different ends of the cell, Pneumatocyst an air filled bladder like organ on many seaweeds that function for buoyancy to. keep the blades afloat in a position to intercept sunlight. Pyrenoids centers of carbon dioxide fixation or starch synthesis within the chloroplasts of algae. and hornworts visible b c of the density of enzymes in that region Pyrenoids are not membrane. bound organelles but specialized areas of the plastid that contain high levels enzymes such as. ribulose 1 5 bisphosphate carboxylase oxygenase RubisCO. Seaweed a macroscopic marine alga This term has no real technical definition and no taxonomic. significance since some seaweeds are more closely related to unicellular or microscopic algae. than they are to other seaweeds, Stipe the stalk between the holdfast and the blades of many seaweeds. Concepts of Botany Algae page 2 of 21,A Dichotomous Key to Freshwater Algae. Using the detachable key to freshwater algal genera on the last page of this lab identify the 10 unknown. monocultures of algae to their respective genera, The algal samples in vials 1 10 are largely monocultures but the presence of other species as. contaminants is possible Often there are small protozoa microscopic animals feeding on the algae in. these vials but do not be distracted by them Focus your keying effort on the majority alga in each. See instructor for the answers at the end of class Important details are viewed at 200X and. 400X or higher magnifications, 0 Working in pairs make wet mounts with coverslips of two of the numbered algae tubes at a time.
from the back Be sure to remember which number each slide is of perhaps by number the slides with. tape and pen, a Do this by placing a drop onto slide be sure to get some algae in it you may have to flush. the tube once with the pipette, b Cover with coverslip be careful laying the cover slip down so as not to destroy large colonial. forms such as Volvox, c Do not let these wet mounts dry out until you are done looking at them. 1 Inspect the alga for color since this is a characteristic you ll often need to identify them. Do this one or both of two ways, a hold the tube up to the light or against white paper. b then be sure to confirm this color again once you ve got it under the scope since some of the. tubes have soil contaminants in them and will make algae in the tube look brown when the cells. are actually green for example, 2 Work your way through the detachable key on the last page to identify the genus You may visit.
section C in the lab manual with information about each algal group to confirm your tentative. identification with pictures or descriptions, 3 Make drawings below and label with genus name the magnification used for the drawing and other. structures such as CHLOROPLAST S FLAGELLUM FLAGELLA PYRENOID S EYESPOT NUCLEUS etc Also record. the color of your algae as seen with the naked eye. 4 After making your identification go to section C in the lab manual on the group and answer the. Concepts of Botany Algae page 3 of 21,Concepts of Botany Algae page 4 of 21. B OPTIONAL per instructor choice difficult to find algae November March Practical Algal. Taxonomy is the scientific discipline that deals with the formal naming classification and identification. of organisms A taxonomic key which you used above is a very useful tool that biologists and people. who monitor water quality use to help identify which algae are found growing in the bodies of water. they are interested in Use the skills from Part B above to answer some of these practical questions. 1 What types of algae or cyanobacteria do grow in the Roddy Pond. Additionally do different species grow at different depths It is conceivable that different algal species. have different preferences in light intensity and temperature and we will test this hypothesis. Sample from Roddy Pond the following note that in winter months november through March most of. the algae are low in the water column or on the bottom near the shore since they are not very active in. photosynthesis,1 Surface the pond scum,2 Sample at 6 inches 18 cm below the surface. 3 Sample deeper between 3 5 feet but do not scrape the pond bottom You may need. to sample from the pier for this deeper sample,4 Place into glass jars vials with lids and label. Concepts of Botany Algae page 5 of 21, 5 Use the detachable dichotomous key to algae and cyanobacteria on the last page to.
identify samples of photosynthetic organisms taken from the pond. 2 Is Roddy Pond safe for cattle or cows to drink from. Farmer s sometimes have major problems with cattle drinking from ponds with high densities of. cyanobacteria see the snippet of the 1999 article by Codd et al on the next page Although. cyanobacteria resemble algae they are bacteria and many cyanobacterial species make potent. neurotoxins that can kill cattle You can use the detachable dichotomous key to algae and cyanobacteria. on the last page to identify samples of photosynthetic organisms taken from the pond Pretend you are. a farmer and if you find cyanobacteria in great abundance then you may have cause for concern. C Groups of Cyanobacteria Algae, Regardless of whether or not you ve seen living examples in lab today read each section and answer. the questions,C1 Group 1 Cyanobacteria blue green algae. Cyanobacteria are photosynthetic bacteria and were sometimes called blue green algae by earlier. botanists but they are very different than the other organisms we typically call algae That is. cyanobacteria are prokaryotes i e they lack a nucleus and membrane bound organelles Whereas. plants and other algae have chloroplasts in their cells to carry out photosynthesis the whole cell of a. cyanobacterium is homologous to a chloroplast Like other prokaryotic cells the cells of cyanobacteria. are much smaller than eukaryotic cells Although cyanobacteria have chlorophyll their different mix of. accessory pigments make them appear bluish green Many are unicellular others are filamentous while. others are colonial, 1 Thought question If you were to have a filamentous or unicellular cyanobacterium. and a filamentous or unicellular alga how might you tell them apart List at least two ways. based on your reading of the above paragraph,Concepts of Botany Algae page 6 of 21. 2 One of the unknown samples from section B was Oscillatoria or Lyngbya which have. filaments which can move or oscillate causing the mass of filaments to move. Did you see evidence for that, What color were the masses of filament in the stock culture tubes or under the.
microscope, 3 Which other genera of cyanobacteria did you find in the mystery monocultures in part A. Cross reference these answers to your drawings in part A above. Figure at left some,cyanobacteria A B,and D E are more or. less colonial since,the cells and or,filaments stick. together in a,gelatinous matrix,Above Cyanobacterial genera. Concepts of Botany Algae page 7 of 21,C2 Group 2 Dinoflagellates.
Dinoflagellates are not bacteria but unicellular protists i e in the Kingdom Protista according to a 5 or 6. kingdom classification scheme, Thus are dinoflagellates prokaryotes or eukaryotes. We do not have dinoflagellates in any of the monocultures in lab today but Roddy Pond sometimes has. dinoflagellates in it note your particular lab may be too early in the season to see any If there are any. sampled in your pond water you will know a dinoflagellate by its olive brown color due in part to. accessory pigments PERIDININ or FUCOXANTHIN and their elaborate shapes and ornamentation. Interesting phenomena in nature include bioluminescence and red tides caused by some marine species. How many cells is each dinoflagellate, Inspect your samples and the pictures below How many flagella do these have and how is each. arranged to help them move, Read in your textbook about the armor or plates p 334 Are the plates inside or outside the. cell s What are they made of How is this the same or different than a cell wall. Figure above Various forms of dinoflagellates,Concepts of Botany Algae page 8 of 21. C3 Group 3 Euglenoids, EUGLENA PLANT OR ANIMAL Remove a drop or two of the freshwater sample containing Euglena.
gracilis Euglena gracilis is just one of many ca 800 900 unicellular species of the genus Euglena They. do not have common names like birds or trees so we have to refer to them by their scientific name. Euglena are interesting because they combine superficial characteristics of both plants and animals. They can make their own food like a plant through photosynthesis but they can also eat other things. like an animal although they actually eat more like an amoeba through phagocytosis than an. animal They can also swim and move thanks to their flagellum Scientists argued for years about which. Kingdom to put them in Animalia or Plantae Right now they are in neither according to some. classifications they are in the Kingdom Protista with other simple often microscopic eukaryotes such. as amoeba and paramecium Protists are eukaryotes typically small or microscopic which lack sufficient. characteristics to otherwise justify their inclusion in the animal plant or fungal kingdoms. A euglena s body is unicellular The outermost envelope is the plasma cell membrane beneath which. lies the pellicle a matrix of protein bands that spiral down the length of the cell The pellicle helps the. euglena maintain its distinctive shape although it is quite flexible and can be flexed by the cell in an. inch worm type fashion Euglena typically store their excess carbohydrates as paramylon a polymer of. glucose related to starch distributed throughout the cytoplasm as paramylon bodies Their. chloroplast pigment profile is similar to that of green algae and plants chlorophyll a b and carotenoids. At one end of a cell is a contractile vacuole which helps expel excess water absorbed by the cell from its. freshwater environment,Concepts of Botany Algae page 9 of 21. Sometimes since they live in water if there are millions of euglena together they form a mat on the. surface of a pond or marsh that you can see It looks slimy a lot like algae Some people say it looks like. pea soup Euglena get into swimming pools too if they are not cleaned regularly. 1 Are euglena unicellular or multicellular, 2 Are euglena animals plants protists or bacteria Prokaryotic or eukaryotic. 3 What organelle carries out photosynthesis, 4 Are euglena autotrophic or heterotrophic Explain. 5 How many flagella did the euglena from the unknown algal cultures above have. 6 Does the flagellum or flagella work by pulling or pushing the cell through the water. Use the detachable dichotomous key to algae and cyanobacteria on the last sampled in your pond water you will know a dinoflagellate by its

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