Tugas Terstruktur 1_BioDas II - Biologi Dasar II Semester Genap 2015\/2016 Tugas Terstruktur 1 TT1 Topic 1 Could Nonvascular Plants Have Caused

Tugas Terstruktur 1_BioDas II - Biologi Dasar II Semester...

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Biologi Dasar II Semester Genap 2015/2016 Tugas Terstruktur 1 TT1 - Topic 1 Could Nonvascular Plants Have Caused Weathering of Rocks and Contributed to Climate Change During the Ordovician Period? [T.M. Lenton, et al, First plants cooled the Ordovician. Nature Geoscience 5:86-89 (2012)]. The oldest traces of terrestrial plants are fossilized spores formed 470 million years ago. Between that time and the end of the Ordovician period 444 million years ago, the atmospheric CO2 level dropped by half, and the climate cooled dramatically. One possible cause of the drop in CO2 during the Ordovician period is the breakdown, or weathering, of rock. As rock weathers, calcium silicate (Ca2SiCO3) is released and combines with CO2 from the air, producing calcium carbonate (CaCO3). In later periods of time, the roots of vascular plants increased rock weathering and mineral release by producing acids that break down rock and soil. Although nonvascular plants lack roots, they require the same mineral nutrients as vascular plants. Could nonvascular plants also increase chemical weathering of rock? If so, they could have contributed to the decline in atmospheric CO2 during the Ordovician. How the Experiment Was Done The researchers set up experimental and control microcosms, or small artificial ecosystems, to measure mineral release from rocks. First, they placed rock fragments of volcanic origin, either granite or andesite, into small glass containers. Then they mixed water and macerated (chopped and crushed) moss of the species Physcomitrella patens . They added this mixture to the experimental microcosms (72 granite and 41 andesite). For the control microcosms (77 granite and 37 andesite), they filtered out the moss and just added the water. After 130 days, they measured the amounts of various minerals found in the water in the control microcosms and in the water and moss in the experimental microcosms. Data from the Experiment The moss grew (increased its biomass) in the experimental microcosms. The table shows the mean amounts in micromoles (µmol) of several minerals measured in the water and the moss in the microcosms.
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Interpret the Data1.Make two bar graphs (for granite and andesite) comparing the mean amounts of eachelement weathered from rocks in the control and experimental microcosms.2.Overall, what is the effect of moss on chemical weathering of rock? Are the results similar ordifferent for granite and andesite?3.“Life has profoundly changed the Earth.” Explain whether or not these experimental resultssupport this statement.TT1 - Topic 2What Can Genomic Analysis of a Mycorrhizal Fungus Reveal About Mycorrhizal Interactions?[F. Martin et al., The genome ofLaccaria bicolorprovides insights into mycorrhizal symbiosis,Nature452: 88–93 (2008)]The first genome of a mycorrhizal fungus to be sequenced was that of the basidiomyceteLaccaria bicolor.In nature,L. bicoloris a common ectomycorrhizal fungus of trees such aspoplar and fir, as well as a free-living soil organism. In forest nurseries, it is used in large-scaleinoculation programs to enhance seedling growth. The fungus can easily be grown alone in
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