From Unicellular to multicellular -> a modern example

Praeses

Praeses

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The Colonial Theory @ wiki

Just the other day I was explaining to my brother of Dictyostelida (Bryce's naming system) and just 5 minutes ago I was reading about this similar theory.

Some photos of the cute lil buggers
1 - Aggregation
2 - Slug
3.1 - sporangium formation
3.2
4 - Sporangium up close
4stages of life cycle

So basically, you have amoebas (unicellular) which feed etc. then under certain conditions they aggregate into a slug-shape (multicellular) followed by sporangium formation (differentiation) and spore proliferation.

website with updated new discoveries made about Dictyostelida
Videos

Awesome, aren't they?
 
Wow.. that's really awesome. And no, I have no idea what I'm looking at, but I'm going to wiki it and pretend to know :D

Ok... from what I understand is that they're mould, that start off as a unicellular organism and then (to quote wiki) become a "multicellular assembly, called a pseudoplasmodium"... Except that they're not really "plants" so much as they are "animal" to quote wiki again...

You'll have to explain this to me in lamens terms - if you'd like :D I can't help but find this interesting...
 
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Well originally they were called "slime-moulds" because they have some mouldy/fungi characteristics. They have some animal characteristics as well.
Mouldy char: Forms a "stalk" and disperses "spores"
Animal char: Amoeboid (like an amoeba) movements. Feeds on bacteria like amoebas.

So you have the amoeboid form which consists of 1 cell. This amoeboid cell lives in its environment and under certain conditions, all these amoeboid cells are attracted to each other (cyclic adenosine monophosphate (cAMP) attraction). They then "climb" onto each other, differentiate (change of cell into specific kind of cell) accordingly to form specific structures (stalk, spore baring structure, "spores"). The "spores" are then released and once conditions are favourable, they "hatch" and release 1 new amoeboid cell per "spore".
Anti-evolutionists love bringing up "you can't observe unicellular, like bacteria, into multicellular organisms, like animals". This "slime-mould" is an example that such a mechanism has evolved once.

Bryce (http://www.mycolog.com/) calls slime-moulds "Protozoan Pseudofungi" which some would say is a more accurate name for these interesting critters :)
 
That's really awesome... And mindboggling, at least for me :D

Where would one find these creatures?

And... I'm so glad I don't do microbiology :D This stuff would make my head spin backwards! :p
 
Slime moulds can be found in damp and dark forest floors. Slime moulds tend to grow on rotted wood after rainfall. Slime moulds generally move only about 1 millimetre per hour, although some can reach 2 centimeters per minute. These scavengers engulf their food, which can include bacteria, fungi, yeast and decaying organic matter, and can eject inedible material.
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wiki :D
 
Ooooooooooh.......... I.. just read the "Slime moulds can be found in damp and dark forest floors" bit... and assumed that was the extent of it... Damn my skim-reading... So rotted wood then? ... Awesome ^.^

And they really are incredible... And... >.> Cute >.>
 
Some people have some as pets in petridishes (for bacterial growth) and they add rolled oats. I want one badly :P
 
Pets? Rolled oats? I'm guessing you have the microscope and all that for it? :D

That could be really kewl. But I'm more of a kitty cat person, personally ;) I like to snuggle and cuddle wiff my pets :D

I still think that ... uhh... the wittle buggers (and face it, that's the only way I'll remember them) are really interesting. Just makes me feel all warm and fuzzy inside knowing that the world is so incredible and has so many amazing things in it. Dictyostelida ... Dictyostelida... Dictyostelida.... hahaha... I can remember how to spell it with my eyes closed. Dictyostelida, and dictyostelidae for the plural? Right? Crap.. wrong... it's dictyosteliidae... damn you wiki and your correctness...

Sorry.. I like words :D Either way, while I am now able to spell it... I won't remember it after I go to sleep ;)

Thank you for teaching my something new though, Praeses :p
 
I read this tread because I also carry 2 cell phones with me (went from uni-cellular to multi-cellular):D:D:D
Silly me!
 
Ratsalad said:
I read this tread because I also carry 2 cell phones with me (went from uni-cellular to multi-cellular):D:D:D
Silly me!
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lol, fool :p

Lycanthrope said:
Pets? Rolled oats? I'm guessing you have the microscope and all that for it?

That could be really kewl. But I'm more of a kitty cat person, personally ;) I like to snuggle and cuddle wiff my pets

I still think that ... uhh... the wittle buggers (and face it, that's the only way I'll remember them) are really interesting. Just makes me feel all warm and fuzzy inside knowing that the world is so incredible and has so many amazing things in it. Dictyostelida ... Dictyostelida... Dictyostelida.... hahaha... I can remember how to spell it with my eyes closed. Dictyostelida, and dictyostelidae for the plural? Right? Crap.. wrong... it's dictyosteliidae... damn you wiki and your correctness...

Sorry.. I like words :D Either way, while I am now able to spell it... I won't remember it after I go to sleep

Thank you for teaching my something new though, Praeses :p
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lol nah you don't need a microscope. They are plentiful so you see slimy structures grow! hehe
Tis a pleasure.
 
So basically this tame pot of snot gives you a mini picture of evolution in action? :p
 
Gru said:
So basically this tame pot of snot gives you a mini picture of evolution in action? :p
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it merely shows that evolution has caused the ability to go from unicellular to multicellular once in modern times (in the past few thousands of years or more) so it could've happened ages ago. People generally don't see how animals could've evolved from something like a bacterial cell which is unicellular but this shows that it could've happened since an "intermediate" form which shows these characteristics exists today still. (I'm not saying we evolved from slime molds)
Keep in mind that all organisms we observe in nature are modern ones. A bacterial cell in modern times is very complicated. ;)
 
Are not blue bottles multicellular organisms made up of different unicellular animals?
 
w1z4rd said:
Are not blue bottles multicellular organisms made up of different unicellular animals?
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I believe it's more the case of a multicellular organism living in symbiosis with unicellular ones. Not sure though.
 
Nah. Endosymbiotic theory is about bacterial-like cells living inside other cells while generating energy to the host cell and receiving nourishment and protection in return which led to the formation of organelles; mitochondria and chloroplasts in eukaryotic organisms :p
 
It seems like the mitochondria are still their own little life forms. Don't they still replicate themselves? separate from the host cell? They still seem to be doing their generating energy part.
 
Siphonophora is an order of the Hydrozoa, a class of marine invertebrates belonging to the phylum Cnidaria. They are colonial, and the colonies may superficially resemble jellyfish. The best known species is the Portuguese Man o' War. Each Man o' War is a colony.

Siphonophora are especially scientifically interesting because they are composed of medusoid and polypoid zooids that are morphologically and functionally specialized. Each zooid is an individual, but their integration with each other is so strong that the colony attains the character of one large individual; and most of the zooids are so specialized that they lack the ability to survive on their own. Thus it is debatable whether zooids or siphonophora are individuals. Also, because complex multicellular organisms have cells which, like zooids, are specialized and interdependent, siphonophora may provide clues regarding their evolution.[1]
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from wiki
 
w1z4rd said:
It seems like the mitochondria are still their own little life forms. Don't they still replicate themselves? separate from the host cell? They still seem to be doing their generating energy part.
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I believe they replicate when the host cell replicates (due to the conditions in the cell...i.e. specific signals leading to cell division).
They do however resemble bacteria in many ways. They have their own ribosomes. Ok, all cells have ribosomes but they have bacterial ribosomes, bacterial ribosomal RNA(which phylogenetically (according to ribosomal RNA sequences) place them in the Bacteria domain.) and bacterial ribosomal-subunits. They also contain their own DNA. They show many signs of bacterial descent.
 
I found this from wiki regarding their sex habits:

Mitochondria replicate their DNA and divide mainly in response to the energy needs of the cell; in other words, their growth and division is not linked to the cell cycle. When the energy needs of a cell are high, mitochondria grow and divide. When the energy use is low, mitochondria are destroyed or become inactive. At cell division, mitochondria are distributed to the daughter cells more or less randomly during the division of the cytoplasm. Mitochondria divide by binary fission similar to bacterial cell division. Unlike bacteria, however, mitochondria can also fuse with other mitochondria.
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