Observe protozoa




Дата канвертавання25.04.2016
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You can observe protozoa by taking a sample of pond water and viewing it under magnification. A compound microscope is necessary to see any individual protozoa, although you can see the largest colonies of protozoa, such as volvox, with just a 30x stereo microscope. Scoop a cup or so of pond water (or water from a puddle or river) into a jar. You should view the protozoa specimens within 24 hours, as the composition of the sample changes over time. Some pond water specimens, such as daphnia, hydra, and planaria, are visible without magnification, since they are multicellular. However, all protists are too tiny to see without magnification of at least 100x. (If you don't live by a pond, you can use our protozoa hatchery kit to grow your own specimens.

To look at protozoa with a compound microscope, use a medicine dropper to put a drop of pond water onto a concave slide. Cover the drop with a slide coverslip,



and then view the slide on high power.


Group

 

Key features 

Bacteria 



single celled, dots or strands, just visible with strongest magnification, cyanobacteria are larger 

Protozoa 



single celled, with tiny hairs or pseudopodia 

Algae 



single celled, mostly green, sometimes yellow-brown 

Rotifers 



wheel-like, hairy appendages, transparent, free swimming or attached 0.2 - 1 mm

Gastrotrichs 



two tails, hairy, round mouth opening
0.1 - 0.5 mm

Worms 



long thin body, many non related forms 

Bryozoa 



plant-like or jelly-like colony, crown of tentacles
individuals: 0.25 - 5 mm

Hydra 



green brown or colourless, body and tentacles contract and stretch 
extended: 20 mm

Water bears
(Tardigrades)



8 stumpy legs, slow moving
<1 mm





Protozoa


Group

 

Key features 

Micscape links

Flagellates
(those that photosynthesise are often classed as algae)



one or more flagella (whip-like cilia), phytoflagellates are green/ photosynthesise, zooflagellates are not green
<0.4 mm

Flagellated protozoa - includes Euglena, Volvox

Some other common types: Monads e.g. Bodo, Choanoflagellates (flask-shaped with flared collar)



Amoeba



move with pseudopods
0.02 - 5 mm

Amoeba - Protozoa portraits
Amoeba - Video gallery
Amoeba - Smallest page on the web
Amoeba proteus - imaged by different illumination methods

Shelled amoeba



amoeba with a shell e.g. of sand grains
0.1 - 0.4 mm

Protozoan houses - testate amoeba, Arcella, Nebela

Some other common types: Chaos, Pelomyxa



Heliozoans
'Sun animalcules'



immobile, spherical with radiating hair-like pseudopods 
0.01 - 1 mm

Smallest page on the web - Heliozoans, Actinosphaerium 

Some other common types: Actinophrys, Acanthocystis



Ciliates - Peritrichs



cylindrical or bell-shaped bodies, undulating membrane of cilia, some stalked, often colonial and attached to animals or plants bell: <0.25mm 

Bell animalcules in 3D - Campanella
Ophrydium - colonial, unstalked
Vorticella - observations on its motile stage

Some other common types: Vorticella, Carchesium



Ciliates - Suctoria 



on water plants and other animals, adult ciliates have lost cilia, sticky tentacles capture prey <0.7 mm

Acineta - Suctoria, ciliates in disguise
Podophyra - an interesting ciliate
Some other common types: Tokophyra, Dendrocometes (lives on gill plates of f/water shrimp)

Other ciliates


Coleps

Lacrymaria

Paramecium

Stentor

Spirostomum

various, mostly free living forms

cell usually of a fixed shape but can be contractile, or extending neck, cilia of various forms, fixed mouth


0.01 - 4 mm





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