|Lichens, Tardigrades, and SO2||Guided Research Further Research|
Results of Study
Results of Study
The conclusions of science depend on experiments. When well-designed experiments are performed and analyzed, many issues may be settled. But the new knowledge derived from well-run experiments also engenders new issues, and this becomes a part of the creative growth of science. Were you able to answer the research question that directed your research? Were there other variables that prevent you from making a claim to knowing something? Can you refine your work to get a better result? These are questions that you should be asking yourself as you continue your work.
Also, as you were working, you no doubt had other areas of concern and interests come up. Remember to refer back to the research questions that have been submitted by the PathFinder Science community as a part of this guided research.
Advanced Tardigrade Research - The International Tardigrade Survey extends the work of the sulphur dioxide project and seeks to identify what species of tardigrades live on the planet and where they live. Online keys to the known species of tardigrades will aid in identifying the specimens. Three levels of Advanced Research have been developed for PathFinder Science researchers. The Tardigrade Mentor will be actively involved with the researchers through the discussion area and by e-mail. The Mentor will also help students develop their own research questions.
Many species of invertebrates live on and among lichens, using them for concealment, shelter, or food. Over half of the orders of insects have associations with lichens. There are striking cases of insects mimicking lichens, the most well known being that of the peppered moth (Biston betularia) on lichen-covered tree bark.
Lichens are a part of many food webs which include invertebrates and their predators. For example small lichen-eating arthropods, such as mites or barklice, may be preyed upon by spiders (which sometimes camouflage their nests with lichen) which are in turn eaten by shrews which themselves are snatched up by owls or hawks. One research study found that Natural forests had significantly greater invertebrate diversity than managed forests and nearly five times as many invertebrates per branch. The number and biomass of invertebrates were related to the number of lichens, even after controlling for sampling location and branch size.
Many lichen species contain bitter compounds that may discourage feeding by invertebrates. Lichen palatability to invertebrate herbivores is based on chemical defense, and that chemical defense is related to nutritional status. As yet, however, very little is known about the nutritional quality of lichens or the nutritional requirements of invertebrates that consume lichens." Invertebrates that are considered pests from the human economic point of view, such as gypsy moths, may be deterred by lichens' anti-herbivore chemical defenses. Invertebrates often carry bits of lichen with them as they go about their business; they are considered to be important agents of lichen dispersal.
Lichens as bioindicators of air quality provide and addition rich area to explore. When they are exposed to some kinds of air pollutants, especially to sulphur dioxide (SO2), lichens are injured and die. The coverage of lichens on trees may make a good indicator of air pollution. The effect of these pollutants may also be observed on the distribution and diversity of a simple community living on the lichens, the tardigrades, but this relationship needs to be explored and better understood.
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