Coloniality in Chlorella vulgaris
Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella.

www.talkorigins.org...

Folks,
Glen in a recent post (Mon, 25 Nov 1996 19:27:26) cited "the change in
family in a microscopic single celled creature which was observed to
suddenly become a multicellular life form." In the post he refers to
Talk Origins post of an alga, Chlorella pyrenoidosa (vulgaris) that
changed its form to "being in the genus Coelosphaerium, which is in a
different family from Chlorella" (Quote from Boxhorn). Sorry folks not
everything, even on the venerable Talk Origins is good science, and this
WOULD NOT be a good example to cite for speciation. It is not Glenn's
fault (he can hardly be expected to know algae genera). In fact I don't
even recall the genus, Coelosphaerium, and I TAed phycology once at the
U. of Illinois. But I do know how easy it is to contaminate cultures
and that I lot of the colonial (better term than multicellular) forms
can have unicellular stages.

But when I looked up the genus Coelosphaerium in my phycology (algae)
text, I found that it was not only a different family - it was a blue
green. This would have implied a kingdom switch from a eukaryot (having
a nucleus) to a prokaryot. While more devolution, that would be an
earth shaking change, which if provable could be published in Science
and not posted to folks that don't know algae (most protozoa folks don't
either - so maybe the researchers thought it just changed its form). It
was most likely a case of contamination. I raise some algae for class
and it is not that easy to get unialgal cultures and keep them that way.
I have had several of mine get contaminated by blue greens. Might also mention that many of the marine algae have a life cycle which has two radically different forms. In one form they can be a filamentous structure and in another part of their life cycle a different enough form that sometimes the same alga was originally classified as two different genera. A good example of this is some of the large Kelps, big brown algae, that have a gametophyte stage (1N) that is filamentous and microscopic.

Originally posted by papabryant

Coloniality in Chlorella vulgaris
Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella.

www.talkorigins.org...

Except for the irony of mentioning Chlorella Pyrenoidosa, which I'm researching as a chellation agent for my autistic son, nothing you mentioned here helps your case.

You see, at this site -

YOU stand accused of being yet ANOTHER internet know-nothing who fails to research far enough, who attempts to pass off attitude as scholarship, and who presumes to question those who have credentials, however minor, based on nothing more than your own bigotries. And as this post shows I caught you in the act for all to see!

I AM STILL WAITING FOR YOUR CREDENTIALS FOR POSTING ON THIS SUBJECT.

Abstract. Members of the Chlorella species are very simple unicellular algae, easy to cultivate and widely used in various physiological studies. Their morphological and physiological characteristics, however, normally change with the environment, making species identification difficult.

A. Chlorophyta (green algae)-molecular classification places these with plants

1.Are extremely varied
a)Contain chlorophylls a and b and carotenoids; store carbohydrate as starch; cell walls are made of cellulose
b)Live in fresh and salt water, soil, and associated with other organisms
c)Can be unicellular, colonial, filamentous, membranous, or tubular
d)Exhibit both asexual and sexual reproduction

2.Genus Chlamydomonas-Members of this genus are microscopic, rounded, with two flagella at anterior end; have single haploid nucleus, a large chloroplast with conspicuous pyrenoid for starch production and storage, a stigma (phototactic eyespot), and contractile vacuole (acts as osmoregulator); exhibit asexual reproduction (zoospores) and sexual reproduction

3.Genus Chlorella-members of this genus are nonmotile, unicellular algae; are widespread in aquatic habitats and in soil; only reproduce asexually; lack flagella; have eyespots, contractile vacuoles, and a very small nucleus

4.Genus Volvox-members of the genus exist as hollow spheres made up of a single layer of 500-60,000 flagellated cells; flagella beat in a coordinated fashion; some cells are specialized for reproduction
Prototheca moriformis, which is common in soil, causes the disease protothecosis in humans and other animals

Examples
Unicellular: Chlorella
Though only about ten species are known in this genus, it plays an important role as endosymbionts
inside the tissues of other organisms. Sponges, polyps, ciliates, and forams all may house Chlorella
internally, providing a home for the alga in exchange for its photosynthates. Chlorella is also
ubiquitous in soil and occurs in both fresh and marine water. Chlorella are extremely well adapted
endosymbionts. Investigations by Karakashian and Karakasian (1965) show that about half of all
chlorella species are succesful in infecting Paramecium bursaria.
Picture : Left : Paramecium bursaria infected with Chlorella., Right : Chlorella attempting to

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penetrate a Paramecium
Chlorella cells are thin walled and spherical. The wall contains the protein sporopollenin (Atkinson, et
al, 1972). Cell type matches that of a typical non-motile cell in chlorophytes.
Reproduction in Chlorella is exclusively asexual, and is proceeded with the formation of 2 , 4 or 8
autospores.
Chlorella is used as a laboratory specimen in the study of photosynthesis.

Chlorella is a genus of single-celled green algae, belonging to the phylum Chlorophyta. It is spherical in shape, about 2 to 10 μm in diameter, and is without flagella. Chlorella contains the green photosynthetic pigments chlorophyll-a and -b in its chloroplast. It depends on photosynthesis for growth and multiplies rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals.

Originally posted by papabryant

They do nothing of the kind; there was contamination (as you own original quote noted - remember the "backflush"?) so all that happened is a blue-green algae colony grew and took over the Chlorella culture dish. Talk about not knowing science, and being intellectually dishonest. You're caught. Toast. Stick a fork in you.

ahh they were in the second tank and the pump system ..that explains it

and bieng unable to predate them (the flagellate) they became the dominante species in the second tank

ahh that explains it then

first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage

the second tank was the observational tank they would have been spotted already being so able to dominate the tank

they also wernt observed in the second tank until after they began to dominate the closed system after the flushing incident so hadnt come from there

maybe they appeared by magic

and why would an already established colonial algae vary so widely before settling down to a regulated number of cells? if it was a contaminent it would stick to its already established colony size wouldnt it? looks like it acted more like somthing first forming a colonial nature and the multipul colony counts would show the variation until it settled to a naturally protected but not over crowded colony wouldnt you say?

after all a simple muscelige covered none motive colony if it got to large would prevent the cells at the bottom from gaining enough light for an acceptable level of photosynthesis

the lower cells would starve to death or at the very least be weakened lowering the colony number to a more acceptable level until all were able to photosynthesis and were protected from the flagella which would lead to a standardisation of cell counts in the colony, wouldnt it?

And posting generalized descriptions of genus, species, family, etc. only makes you look even more foolish. Not one word of it meant anything to the fact you are claiming a clear case of contamination in a petri dish is proof of a change in classification.

your the one having to claim external contamination on a closed system as they were unobserved in either tank until several days after the back flush when they appeared in the primary tank (the tank that never needed to be opened to obtain samples) and later got carried to the secondary

the contamination was the flagellate from tank 2 into tank 1, no magically appearing other stuff

remember in a two stage continuous system you set up the first stage and prevent contamination becasue it would screw up the entire experiment, and if you were sloppy enough to accidentally contaminate the second stage you can just replace it rather then the whole setup

a stage 2 contaminent would be found in both systems at the same time, not start in the first stage then migrate


WANT TO KNOW REALLY WHY HE MISCLASSIFIED THEM?
(and you thought i posted those genus descriptions for fun )

there are no none motive cloraphyta algae that are colonial(or wasnt until they appeared in his experiment, dont take my word for it scroll up and check the links that describe the genus's in the cloraphyta family), volvox have flagellum and as such are colonial and motive so they dont fit in there

see he looked for the next closest thing

Classification: Empire Prokaryota Kingdom Bacteria Subkingdom Negibacteria Phylum Cyanobacteria Class Cyanophyceae Subclass Synechococcophycideae Order Synechococcales Family Merismopediaceae Subfamily Gomphosphaerioideae Genus Coelosphaerium

Description: Unicellular - colonial; colonies microscopic, spherical, free-living (mainly planktonic), enveloped by colorless, indistinct or limited fine mucilage, without any inner stalk system, cells situated in one layer near the surface of colony. Cells spherical, mainly distant from one another, peripherally situated, found more densely in old colonies than in young ones, pale or bright blue-green, 2 species with aerotopes.

TRANSLATION: I have no credentials.

TRANSLATION: Papa's exposed me for the fraud I am, but I can't lose face infront of all the other 14 year old skeptics here by admitting he's made me his beotch, now can I?