Did Precambrian land look like this? David Geiser, Penn State The largest genetic study ever performed to learn when land plants and fungi first appeared on the Earth has revealed a plausible biological cause for two major climate events: According to the authors of the study, which will be published in the 10 August issue of the journal Science, plants paved the way for the evolution of land animals by simultaneously increasing the percentage of oxygen in the Earth's atmosphere and decreasing the percentage of carbon dioxide, a powerful greenhouse gas. The researchers found that land plants had evolved on Earth by about million years ago and land fungi by about 1, million years ago — much earlier than previous estimates of around million years ago, which were based on the earliest fossils of those organisms.
The findings were based upon chamber studies involving injection of a pollutant into a small, sealed chamber and following the pollutant decay, with and without plants present. Other studies examining this effect followed. Today, even a casual search of the internet will find many articles extolling the benefits of using plants as indoor air cleaners.
However, there has been little critical analysis of the application of plants to actual indoor environments and only a few field studies have been conducted.
A critical review of results of both laboratory chamber studies and field studies leads to the conclusion that indoor plants have little, if any, benefit for removing indoor air of VOC in residential and commercial buildings. Finally, recommendations for improving future studies are presented.
Today, a search of the internet will find many articles promoting the use of plants as indoor air cleaners. While several scientific papers have been published on studies of pollutant removal by plants in small test chambers under controlled conditions, as yet, there has been little critical analysis of the studies and their results.
Far fewer field studies have been published. This paper will briefly review results of both laboratory chamber studies and field studies, followed by a critical analysis of these results and the implications for indoor air cleaning.
The findings were based upon studies involving the introduction of a pollutant or pollutants into a small, sealed chamber. The chamber volumes typically ranged from 0.
The decay of the pollutant concentration over time, with and without plants present, was then followed. Wolverton and colleagues later conducted tests on the removal of benzene and trichloroethylene at concentrations ranging from 0.
The reported reductions ranged from 9. Studies examining this effect by other researchers followed. For example, Wood et al. Quantitative results were not given for the concentration reductions but estimated concentration vs.
HBI sampled for toluene, xylene, 1,1,1-trichlorethane and benzene for several months in two very similar floors of an office building in Arlington, VA, USA.
Identical ventilation systems on both floors had their outdoor air damper set and unchanged for the duration of the study. For the first month, no plants were on either floor; for the next four months, plants were only on the 9th floor; and for the last four months, plants were on both the 9th and the 11th floors.
The presence of plants produced no reduction of pollutant concentrations. Five plants five species were added to each room every two days to a maximum of 20 plants at 2. Two adjacent portable office buildings were used as controls with no plants.
The mean formaldehyde concentrations were about ppb, except with 20 plants. In one building, the nine offices studied were served by three separate air-conditioning systems; in the second building, the eight offices studied were served by a single air-conditioning system, supplying about 0.
In the third building, nine offices were studied in the first phase, and eight offices were studied in the second phase.What is Botany? Botany is the scientific study of plants.
"Plants," to most people, means a wide range of living organisms from the smallest bacteria to the largest living things - the giant sequoia trees. By this definition plants include: algae, fungi, lichens, mosses, ferns, conifers and flowering plants. The Seed Site: A study guide with a table on the classification of plants starting from the highest category.
Elementary Science Plant Classifications: An easy to read page catered to elementary students to learn about different classifications of plants in .
Crossword Solver - Crossword Clues, synonyms, anagrams and definition of study of plants. Palaeobotany is the study of extinct plants (6) or fossilised plants recovered from geological strata (12).
Palaeobotanists will also study fossilised algae, bacteria, fungi and lichens - just as botanists study modern plants in these taxa. Find answers for the crossword clue: Study of plants. We have 1 answer for this clue. Search Results.
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