Is it ALIVE?

WebQuest for AP Biology

Rebecca M. Deeley

Last summer a student brought me a find from the beach. It looked like a large, mushy biscuit.  It could have been white.  Maybe it was grey.  The questions the student posed were, "Is it alive?" and "What is it?"

I DON'T KNOW!  One thing was certain-it REEKED.  The odor was well beyond rank.  I wondered how my student could drive all the way to campus from the beach with this thing in her car.

I'm pretty sure it was dead, if it had been alive.  It definitely wasn't moving when placed on the lab bench.  Is movement necessary to determine life?

Examination of some of the tissue under low power on the microscope revealed cells.  There were a lot of cells.  They were all alike.  There was no evidence of cilia or flagella.  There was no evidence of cell walls.  It was decomposing.  A cross section of the "biscuit" revealed no organs, no differentiated tissues.  There was no cavity.  This was dense.  How did cells on the inside exchange nutrients and wastes with the environment?  Are cells necessary for life?  Are tissues and organs necessary for life?  Is nutrient exchange necessary for life?

We took a small sample and tested for the presence of proteins.  There were proteins.
We tested for carbohydrates.  There were carbohydrates.
We tested for lipids.  The test for lipids was inconclusive at best; probably negative.
We tried staining samples to look for a nucleus or a nuclear region.  Our staining techniques weren't good enough or the tissues were decomposed to the point where we were unable to determine if there was a nucleus or a nuclear region.
Are all macromolecules necessary for life?

It was bigger than a cell.  It was an accumulation of cells.
Is growth necessary for life?

It wasn't accompanied by baby stinky biscuits.  Many species provide no parental care, so babies are not always accompanied by parents.  Some life forms simply divide by fission.  "Mother" and "daughter" cells are alike.  Some life forms as juveniles are completely different from the adult stage.
This was a mushy biscuit through and through without evidence of reproductive structures or offspring.  Is reproduction a necessary characteristic of life?

The mushy biscuit in question was found on the beach.  Maybe it lived on the beach.  Maybe it lived in the ocean.  If it lived on the beach, how did it tolerate extreme temperatures?  If it lived in the water near the shore, how did it tolerate a range of salinities?  Is homeostasis necessary for life?

So what was this odiferous biscuit and was it alive?