Using the microscope, we saw a creature eating some leaves of lettuce. It was transparent and nearly 0.1-0.5 mm long. It was a rotifer. It is a microscopic aquatic animal which can be found in freshwater environments like lake bottoms, or flowing water environments such as rivers or streams.

Rotifers have a long body made of three sections: a head, a body, and a foot. The foot usually has two toes. The head of a rotifer has a large, mouth, surrounded by cilia. The rotifer's cilia are used to take food and to move in the water.
Rotifers are not favored for fossilization because of their very small size.  They are mostly used in aquaculture and aquariums because of their very high reproductive rates.

Back to table of contents 

The rotifers are little organisms with bilateral symetry. They have a side between 50 micrometers and 3 millimeters. They have lashes around their mouse and these lashes make them move forward. Some rotifers are free swimming, others move by inchworming along a substrate, and some are sessile, moving inside tubes or gelatinous holdfasts that are attached to a substrate. Rotifers are an important part of freshwater zooplanktons being a major foodsource and with many species also contributing to the decomposition of soil organic matter.

Back to table of contents

The vessel element from lettuce

A vessel element is a little spiral shaped object in the wall of the vessel that carry sap and water in the plant. The vessel element is made of lignin the same molecule that composed the wood.It’s utility is to prevent the vessel from collapsing on itself,because the lignin make it very hard. When the lettuce die,some little organisme start eating the lettuce and the vessel,and only left the hardest part,the vessel element.

return to table of content

Paramecia is a living organism belonging to the large named the ciliated protozoan. His size ranges from 100 to 300 microns. This unicellular animal uses his numerous cilia to move and feed off bacteria and small algae.

The paramecium is a fresh water organism found in abundance in ponds, small and slow streams, or biofilms at the surface of puddles and dead plants. The cell nucleus is divided in two parts, a small micronucleus and a large macronucleus. The first one is responsible for the sexual functions which generate genetic variation and the second provides trophic functions and asexual reproduction

Table of contents

Diatoms are a major group of algae, and are among the most common types of phytoplankton. Diatoms are unicellular, although they can form colonies in the shape of filaments or ribbons.Only male gametes of centric diatoms are capable of movement.Diatom communities are a popular tool for monitoring environmental conditions, past and present, and are commonly used in studies of water quality.

Return to table of contents

Diatom

They are a major group of algae. They are also one of the easiest to recognize, because of their unique cell sructure, silicified cell wall and life cycle. They are unicellular and they can form colonies in the shape of filaments. Diatoms are living in both fresh and salt water. They are an essential part of food for the smallest planktonic animals.

Return to table of contents

We did a graph on the turbidity of the  water which is contained inside and the other  was exposed to the sun light. We can know, with it, that the turbidity increases each day. In the graph, you can see the number “465”, it represents the water which become brown. The number “565” says that the light doesn’t shine the water when the turbidity increases. So to conclude, more turbidity increases, more water turns brown and dark.

This graph shows the evolution of the temperature of two artificial puddles during two weeks.

We have measure the temperature of the inside puddle in blue and we have measure the temperature of the outside artificial puddle in red.

Back to table of contents