<h2>
	BEFORE YOU START</h2>
<h3>
	<a name="TOC-Key-Ideas-Introduced-in-this-Unit:"></a>Key Ideas Introduced in this Unit:</h3>
<ul>
	<li>
		Mercury bioaccumulates</li>
	<li>
		Mercury amounts in organisms increase at higher trophic levels</li>
	<li>
		Mercury is toxic to humans and other organisms</li>
	<li>
		Dragonflies are a key part of the aquatic food web and are exposed to mercury</li>
</ul>
<h3>
	<a name="TOC-Concepts-and-Relationship:"></a>Concepts and Relationship:</h3>
<ul>
	<li>
		Mercury can enter organisms in several ways</li>
	<li>
		Mercury stays in the body for a long time</li>
	<li>
		Mercury primarily affects the brain, nervous system, and kidneys</li>
	<li>
		A fetus that is exposed to mercury can be born with severe nerve and/or kidney damage as well as developmental disabilities</li>
	<li>
		A study site contains a lot of components that might all have mercury: soil, water, organisms, plants, etc. (get acquainted with you field site and start thinking about how it may be affected by mercury)</li>
</ul>
<h3>
	<a name="TOC-Vocabulary:"></a>Vocabulary:</h3>
<ul>
	<li>
		Bioaccumulation&mdash;the collection of higher and higher concentrations of potentially toxic chemicals in individual organisms. It occurs in the case of chemicals that are ingested but cannot be broken down or excreted.</li>
	<li>
		Biomagnification&mdash;bioaccumulation occurring through several levels of a food chain.</li>
	<li>
		Food chain&mdash;a set of organisms that feed one upon another linearly, and thus pass energy along the chain. (An herbivore eats a plant, the herbivore is eaten by a carnivore, which is then eaten by another carnivore.)</li>
	<li>
		Food web&mdash;multiple, interconnected food chains. Some animals eat and are eaten by many other types of organisms in a complex web.</li>
	<li>
		Life history&mdash;the sequence and timing of events in an organism&rsquo;s life cycle. For example, some life history traits include how long an organism spends as a larva, what it eats, and when it is ready to reproduce.</li>
	<li>
		Macroinvertebrate&mdash;an organism without a backbone that is large enough to be seen without a microscope</li>
	<li>
		Mercury cycle&mdash;the deposition and uptake of mercury from the emission source to the ingestion by organisms</li>
	<li>
		Methylmercury&mdash;the byproduct of metabolism by anaerobic bacteria, typically living in an acidic environment with access to carbon and sulfur</li>
	<li>
		Study organism&mdash;the organism that is the subject of a research project</li>
	<li>
		Toxicity&mdash;the degree to which something is poisonous</li>
	<li>
		Trophic level&mdash;as organisms eat other organisms, all the substances they contain are passed up the food chain, or up tropic levels. (Producers&mdash;green plants and algae. Primary consumers&mdash;herbivores. Secondary consumers&mdash;carnivores.</li>
</ul>
<h3>
	<a name="TOC-Student-Prerequisites:"></a>Student Prerequisites:</h3>
<ul>
	<li>
		How to measure volume and square inches</li>
	<li>
		How to convert units such as &micro;g/g to ppb or ppm (see Activity A in Unit 1)</li>
	<li>
		Proportions</li>
	<li>
		Averages</li>
	<li>
		Ranges</li>
	<li>
		Computer skills</li>
	<li>
		Library skills</li>
</ul>
<h3>
	<a name="TOC-Misconceptions-about-mercury:"></a><font size="3"><b>Misconceptions about mercury: </b></font></h3>
<div>
	<ul>
		<li>
			Mercury is not a problem in Maine</li>
		<li>
			Quantities of mercury that we ingest are not sufficient to cause harm</li>
		<li>
			There is nothing interesting to study at my site</li>
	</ul>
</div>
