Thanks for your question Samantha!

As I’m sure you know, protists are typically single-celled organisms that tend to live in aquatic or otherwise moist environments.  These creatures are some of the simplest eukaryotes – cells with membrane bound organelles.  Some common protists you might be aware of are amoebae, paramecia, and many common algae (such as kelp).  While most protists do live as single cells, some exist in colonies (such as Volvox spp., which are among the most beautiful organisms in nature in my opinion). 

When thinking about the importance of an organism, I think it is crucial to think of how that organism affects the creatures that occupy its environment.  For instance, small animals such as snails and fish often graze on algae and other protists, and thus derive energy from them.   Additionally many protists are heterotrophs – they derive energy from eating other organisms.  Protists often consume biological detritus such as the remains of dead organisms or other organisms’ waste materials.  Thus protists help eliminate this “garbage” from the ecosystem. 

Some protists, on the other hand, are autotrophs.  They can perform photosynthesis to create complex organic molecules from sunlight.  These organisms, along with other autotrophs such as plants, form the foundation of the food web – without them, more complex organisms would have nothing to eat.  They also produce oxygen as a by-product of photosynthesis, and photosynthetic microbes are thought to have played a major role in the conversion of Earth’s atmosphere from a carbon dioxide-rich atmosphere millions of years ago into the relatively oxygen- rich atmosphere necessary for all plants, animals, fungi and protists to survive today.

Finally, some protists – notably kelp – form large colony structures.  In fact, kelp grows very large very quickly so that entire “forests” of kelp exist in coastal oceans.  These forests form complex mini-ecosystems where certain organisms, such as sea otters, crabs and sea urchins live together in a highly specialized environment.   Kelp is also a major source of food for some of these creatures, especially the urchins. 

One more interesting fact – diatom s, which are protists that have beautiful geometric “shells” made of silcon have two interesting uses.  First, because they are so easily identified by their striking shapes and because they often inhabit only small stretches of rivers and streams, specific diatom shells can be used to figure out where a dead body has been dumped when it’s found downstream by the police.  Second, the fossilized remains of diatoms have numerous uses.  As a scientist I am most familiar with the use of this “diatomaceous earth” to isolate DNA.

I hope this answers your question; sometimes it is difficult to understand the innate qualities of an organism, especially when they are typically too small to be seen with the naked eye!

Regards,

Billy.

 

PS – I’ve included some links you might find interesting, including some Wikipedia articles.  Remember, though, that Wikipedia is a useful resource but is not always accurate, and should probably not be used as a primary source for class work. 

 

Wikipedia article for Kelp.

http://en.wikipedia.org/wiki/Kelp

 

Wikipedia article for Kelp forests.

http://en.wikipedia.org/wi ki/Kelp_forest

 

Wikipedia article for Diatomaceous earth.

http://en.wikipedia .org/wiki/Diatomaceous_earth

 

Wikipedia article for Detritivores (organisms that live off of detritus).

http://en.wikipedia.org/wi ki/Detritivore

 

Brief explanation of Autotrophs.

h ttp://www.windows.ucar.edu/tour/link=/earth/Life/autotrophs.html

 

A nice site from Pennsylvania State University with some nice descriptions and pictures of various protists (check out the volvox near the bottom of the page…I told you they were pretty!).

http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial30.htm

 

A brief overview of using diatoms in forensic cases.

http:/ /sp.lyellcollection.org/cgi/content/abstract/232/1/277

 

A site from UC Berkeley describing diatoms.

http:/ /www.ucmp.berkeley.edu/chromista/diatoms/diatommm.html