Friday, November 15, 2013

My old friends

I ran across some old friends this week.  I was visiting in the classroom of a student teacher and she had students doing a pond water assessment to determine the life forms there.  I have fond memories of my explorations with the microscope in my Biology classroom and I want to share some of my favorite organisms with you.

 In the spring every mudpuddle and ditch with standing water will develop its population of microorganims, and with the coming of hot dry weather the water dries up and with it the “critters” that lived there also dry out...  Many orgnisms have built in genetic instructions to form a protective shell, a cyst, as their last act before drying up.  This is like a space capsule – it carried a living organism through the inhospitable dry summer conditions.

The soil at the bottom of the small pond turns into dust which is blown around. Among the dust particles are the cysts.

Dry grass growing along the road will receive a portion of the dust during the long hot summer.  If a handful of this grass is placed in a beaker of water, the cysts will reemerge – some right away and some take longer.  In nature this occurs with the first rain.

Before the age of modern science it was believed that organisms could form from the soil alone... this was called Spontaneous Generation - now it has been proven that all life comes from previous life,,,

Return to your days of studying biology  and see how many of these you recall...

The popular amoeba – one advanced cell with many of the standard cell parts ( cell organelles).  Flows into one arm at a time – slow transport but it works.

Amoeba can pinch off into two distinct organisms

Flagellates have one or a few long whip like structures which provide an improved system of mobility. Human male sperm also have visible flagella.

These are photosynthetic - and so they use their flagella to move into light.

Ciliates-The outer part of the body has many short hair like cilia – some beat in rhythmic waves...  these guys really zip around in the microscope.

Our old friend the Paramecium cilia occur over the entire cell - but they are only visible here at the upper end.

Another view of paramecium with enhanced micro imaging and with a dye strain

Ciliates come in many forms – here the cilia are concentrated around the ‘mouth’ of the cell

Note the cilia around the mouth opening can draw a stream of water with food into the gullet.

Some microorganism have animal like qualities and must catch and eat food

My absolute favorites! Vorticellas... they not only have cilia around their 'mouth' - then when they catch food their 'stalk' has a spring like quality that can pulls them down

...others are plant like - and can capture sunlight and make all their own food

Photosynthetic one celled protozoa

And some are not equipped for photosynthesis - they are predators 

 Some Microorganisms are multicellular – but still incredibly small. 

Volvox - is like a hollow soccer  ball made up of many photosynthetic cells - the cells all have flagella on the outside which allows the volvox to move into the light